rules of thumb
DESCRIPTION
e-bookTRANSCRIPT
DTttDDtDIItDDDDDDTDDIDIpDDpppppIDpptbBp)
D)
RULES - OF-THT]MB
FORTHEMAN
ONTHE RIG
Second Edition, Revised 1993
Latest Printing - 2007
BylVilliam Murchison
ocopyright l9t8
Murchisor Drilling Schools, lncP.O. Bor 14577
Albuqucrqug Ncw Merico t7l9l
Tclcphorc (5115) 29t4271 Tclcfer (5{15) 1l&5294
I .
tr.
CEAPIER OI,III,INE
INTRODUCTION
MI.JD REI-ATED RI.'LES.OF.THIJMBA. 1. Trip Margin
2. Equivalent Circulating Density (ECD)3. Prressure Loss in Annulus4. Other Facts about Yield Value
B. Plastic ViscositY (PD1. Plastic Viscosity in Weigbted Water-base Mud2. Pla.*ic Viscosity in Weighted Oil or Oil Invert Base Mud3. Plastic Viscosity for Water-base Muds by Weight Ranges4. Other Facts and Rules-of-Thumb about Plastic viscosity
C. Funnel ViscositY (FV;1. Funnel Viscosity (FV) Approximarc Value2. Funnet Viscosity (FV) to Sene as Base for I-CM Pill3. FV vs. APParent ViscositY
D. Apparent ViscositY (Au1. AV Calculation2. AV IfM Base3. 6y $imilar to F\/
E. Solids1. Optimum % Solids (Inw Density Solids)2. Optimum % Sotids (Weighted Mud)3. Rough Estimate for Percent Solids by Vohrme in
Weighted Mud4. Drill Solids and Bentonite Ratio5. Anlyze the Effect of Solids on Rate of Penetration6- Amlyzn Solids Control Equipment
F. Mud Weight @ensitY)
G. Water Inss (Filtration/Fluid Loss)
H. Shale Hydration and DisPersion
Paee
1:1
2: t2 :L2zL2222:3
2:62:62:72|7-
2:72:72:72:7
2:42:42:42:42:5
2:82:82:8
2:g2292:92: l l
2 :13
2:13
2:L3
t.
T
CHAPTER OUTLINE(cont.)
M. TRIPPINGRT'LES-OF.THI'MB
A. Pulling Out of Hole (Tripping)1. Slug Mud Weight2. Dry Prpe vs. Wet Pipe3. Metal Displacement4. Trip Margin5. Tripping in Top Hole
B. Running Pipe in Hole1. Surge Pressure
IV. CASING, CEMENTING A}.ID PLUG SETTING
A. Circulating Time before Ceme.ting
B. Influencing Factors or Why Casing Strings are Run
C. Mix Water for Cement
D. Contact Time
E. Cement Plugs Leaving Cement Head
F. Compressibility Volume when Testing Casing
G. Safe Water Spacer for a Balanced Kick Off Plug
H. Things that Help Avoid Contamination of Kick Off Plug
I. Cement for First Cement Plug in a Lost Circulation Zone
J. Testing Liner and SEreezing Liner if Flow is Observed
V.
Page
3:1
3:13:13|23:33:33:5
3:63:6
4: t
4 .1
4:3-
4:4
4:5
4:6
4:8
4:9
4:10
4:12
4: t3
5:1
IIItIaaIaeICteIIIIIIIIaaIaaaaaaaIIaaaIq!
u.
CEMENT MD(
Mmrchleon Dr{lltnsSchools- IlppP2F?ppTpIDppDpppIDI)
TttI,
IttI,
IIttIIttD)
CUAPIER OUTLINE(cont.)
VI. VOLTJME AT.ID CAPACITY
A. Open Hole Volume
B. Estimatiqg Hole Diameter from tag Time
C. Annular Vohrme in Open Hole
D. Volume of Vertical Cylindrical Tank
E. Capacity of Pipe
F. Capacity of Anrulus Betrreen Concentric Pipe Strings
G. Capacity of Anrulus, Two Inner Strings in Casing
VII. FIT'DRAt'UCS
A. Optimum Hydraulics
B. Hydraulic Guidelires
C. Horsepower at Surface aod Bit
D. Rough Neck Formula
E. Effect of Pipe Size on Hydraulics
F. Effect of Mud Weight and Pla.*ic Viscosity on Hydraulics
G. Equivdent Circulating Density (ECD)
H. Optimum Annular Velocity
vltr. ESTIMATnIG HYDROSTATIC HEAD (PRESSI RE)
Page
6:1
6:1
6:2
6:3
6:3
6:4
6:6
6:6
7:L
7: t
7:2
7:6
7:7
7:8
7:9
7:10
7:12
8:1
9:1D(. ESTIMATII{G STRENGTH OF STEEL CABLE
tu.
Murchison Dtfltine Schools. Inc.
CHAPTER OUTLII\E(cont.)
X. ESTIMATING STRENGTII OF ROPE
)9. MAKE I.'P LOSS IN LINE PIPE WITH STANDARD 8ROI]ND THREAD
)il. CENTRIFUGALPI.'MPS
A. Head in FeetB. Capacity (GPM)C. Horsepower
)iln. BOP ACCLTMUL-TORS
)(tV. KICK TOLERANCE
XV. WATER HAMMER EFFECT
XvI. SHALES
XUI. LOST CIRCI,JI-ATION
XVItr. DIAI\,IOND BITS
)(D(. DIRECTIONAL DRILLING
)O(. STUCK PIPE
)oil. DRILL STEM TESTING (DST)
x)fi. DRILL STRING DESIGN
iv.
Page
10:1
11:1
12: l
12: l12: l12:1
13:1
14:l
15:1
16:1
17:L
18:1
19:1
20:l
2 l : l
22: l
Murclison lhiiline Scrhools. Ita,
ttIt,
tttttIt,
ttttDt,
t,
ttttt)
tttattt,
ttttt
)oiltr.
)o(rv.
)orv.
)o(u.
)ooo.
)ooc.
)ooo.
)o(ur. ESTIMATII{G GAS WELL Fr.oW RATE (MCFD)
)o(uII. ESTIMATING HORSEPOWER REQLIRED TOCOMPRESS GAS
)o(D(. TIIE TEMPERATT'RE DROP ACROSS A PRESSI.'REREGI'I.ATOR
)OO(.A ELONGATION DI.'E TO TEMPERATI.JRE
)OO(.B EIONGATION DTJE TO STRETCH AND TIIEPrsToN (BUOYANCD
)OO(.C TEMPERATURE CONVERSION
)oo(.D DEPRECIATION OF EQLTIPMENT
CHAPIER OUTLINE(cont.)
I,OC'GING RLTLES FOR DRILLING
GAS KICKS AND Bt'BBLE RISE TO SI.'RFACE
MT'D VOLI.JME BI'ILDING FORMI.JI-AS
ESTrN{ATING PRODUCTTON RATE (BpD)
APPENDD( A: CROSS REFERENCE
APPENDD( B: ABBREVIATIONS
APPENDD( C: SI METRIC LJNITS
23:t
24:l
25:l
26:l
27:L
28:L
29:l
30:1
30:3
30:9
30:10
A:1
B:1
C:1
v.
Murchison Ilrillins Schools. IrtfrpIItttrltttrlrltrDrlttttttIttr'tll
ttttt)
I|'
tIIItD
BOOK: RIILES-OF-TIIIIMBFOR TIM MAN ON TIIE RIG
I. INTRODUCTION
The first introduction was written before starting to write a chapter on rules-of-thumb for theMurchison Drilling Schools Operational Manual. It was an introductory comment about theusefulness of about ten rules-of-thumb. However, after starting to jot down a few rules-of-thumb about key drilling operations and practices two things were found wrong. One, a singlechapter would not do justice to rules about a zubject as broad as drilling and; secondly, rules-of-thumb or rules applying to certain drilling operations require more elaboration and examplesthan sliginally planned
Rules-of-thumb have been handed down from one drilling boom to the-next and it is difflrcult toknow to whom the credit should be given. Thanls go out to those that made good observations--took timrc 1e simFlif] the approach--and passed them on down unselfishly. The rules-of-thumbin this book are mostly the rezult of those drilling people who laid the foundation for the drillingindusfiry we have today.
This book includes rules on: Mud; Tripping; Casing and Cementing; Volumes ar-rd Capacity;Hydraulics; Pressure; Strength of Rope and Steel Cable; Centrifugal Pumps; BOP Accumulators;Kick Tolerance; Water Hammer Effect; Shales; Lost Circulation; Diamond Bits; DirectionalDrilling; Snrck Pipe; Drill Stem Testing; Drill String Design; Logging; Gas Kicls; VolumeBuilding; Estimating Producing and Gas Flow Rate; Production Rules on Compre5sing Gas andTemperature Drop Across A Pressure Regulator; Pipe Elongation Due to Temperature, Stretchand the Piston Effect; Temperature Conversion; and Equipment Depreciation.
The book has many examples which simplify the use of the forrrulas and rules. You should beable to make quick approximations and in many cases you may find that these ball-park numbersare better than the so+alled accurate numbers. Practically everyone has a calculator; however,some calculations can be done in your head. These simplified rules are very useful when azupenrisor is on the rig floor or taking a report over the phone or radio.
In summary, you will find many time-tested guidelines that provide historical backgroundexperience collected by many people over several years.
1 :1
MrrmhicrrnDrillinoSnhrnlc fnpl.f.ppItf.pppItpppppFFpftfr||pIIItDD!itblrbbr'tIttItItDl)
N. MTJD RELATED RI]LES-OF.TIITJMB
A. Yield Point (YP) or Yield Value (Y\D
In general F/ is a measure of the atEactive forces between clay particles and has thegreatest influence on operating practices while driUing.
1. Trip Margin (or Operating Mud Weight) sufficient to drill and trip pipe out of hole.
Rule: Divide the hydraulic diameter (diameter of hole minus diameter ofpipe) times 11.7 into the yield value. This number is the tripmargin in pounds per gallon Gpg). This trip margin is added tothe mud weight required to bdance formationpressure under static(non-circulating or non-tripping) conditions.
Formula: Mwr = ,9j*u"H). + lvfwg,r' 11.7 (Dr - DJ 4
Where: MWr = The over balance (mud weight) required toovercome swab and negative surge effect, ppg
Dh : Diameter of hole, in
De : Diameter of drill plpe, in
Yield Value. : e 300 Reading minus PV, Ib/100 ftz
Example: A 14.5 ppg MW is reErired to balance formation pressure.The mud has a yield value of 20. Calculate estimated MW tobalance formation pressure while tripping pipe (to offsetswabbing/negative surge). Hole size is 8.5" and DP is 5".
l v fwr=# +14.5 =15ppg
2. Equivalent Circulating Density (ECD)
The ECD is the effective mud weight on the formation due to the total effectof the mud weight plus the friction loss in the annular space between the pipeand the hole while circulating.
2zl
Murciison Drilline Schools. Inc. I- l
(
IIIIIIIIIIaIIIIIIIIIaIIIIIIIIIIIIIIIIII
3.
II. MIJD RELATED RLILE$OF-TIIITMB (cont.)
A. Yield Point (YP) or Yield Vdue (hD (cont.)
2. Equivalent Circulating Densitv GCD) (cont.)
Rule: For (ppg): Multiply the YV by 0.1 and divide the hydrauticdiameter (diameter hole minus diameter of prpe) into the number.Add this number to the mud weight to arrive at ECD.
For (pcf): Multiply the hydraulic diameter (diameter hole minusdiameter of pipe) by 2 and divide this nrmber into the yV. Addthis value to the mud weight to arrive at ECD.
Forrrula(s): ECD (ppg) = (Yv x 0.1)@o-DJ
* Whor"
+ lvfWoon(Yv)ECD (pcD =
z@r-DJ
Example: Calulate the estimated ECD if the 15 ppg mud has a YV of 20.The hole size is 8-1/2 inches and the DP OD is 5 inches.
EcD = @l=* o-9 + 15 = 15.57 pps(8.5 - s)
Pressure loss in the annulus (rule-of-thumb version of Bingham plastic equation).
Rule: Multiply depth times W and divide by the product of 225 timesthe hydraulic diameter (dianreter hole minus diameter pipe).
222
Murchison Drillins Schools. Ir27ftFftl.ppl.I'pprTpFT!ttttIppIll'f)rlJ'IJ,)
tJ,J'J,)
aaa)
IIl'
tr. MIID RELATED RIILFS-OF-THIJMB (cont.)
A. Yield Point OlP) or Yield Value ClAft (conr.)
3. (cont.)
Forrrula: P-, = @e'Pth x ilr)' 225 (D, - DJ
ECD=MW.* Pr -
=MSy ' . * Wu (Depth x .052) ' 11.7 @r - DJ
Example: Estimate the preszure loss in the annulus and the ECD. The MW is 15 pp1and the W is 20. The depth is 12,000 feet and the hole size is 8-1/2 inchewith 5 inch DP.
ECD=S*L=15.5ppg11.7 (8.5 - 5)
4. Other Facts and Rules-of-Thumb about Yield Value (YV)
a. W (htgh side) : mud weight (ppg). Note: oil muds run higher yield values.b. YV is very temperature sensitive and therefore should be reported at same
temperature each test so that monitoring trends can be effective.c. YV affects overbalance (trip margin) requirements.d. YV affects surge or swabbinge. YV affects hole cleaning Oalance flowrate (O and YV).
1) YV of 3-5 ok big hole for drill chips2) YV of 8-10 in 8-tl2 or smaller hole to help suppress turbulence3) W of qpud mud should b 12 or higher4) W of hole sweep should & t2 or higher5) F/ of directional holes should be higher (use trial & error
to establish)
f. YV 0b/100 ftt) : e 300 reading minus plastic viscosity (on a FannViscometer).
g. s/ in high weight muds gives a good trend on solids (along with PVor solids test).
h. W units are lbs/100 fP (same as gel strengths)
2:3
tr. MttD RELATED RITLES-OF-TEUMB (cont.)
A. Yield Point 0lP) or Yield Value (YV) (cont.)
4. Other Facts and Rules-of-Thumb about Yield Value OaD (cont.)
i. High yield values and gel strengths may be desired to prevent or minimizebridging, poor hole cleaning, drag, high torque and to minimize barite settling.Inw yield values and gel strengths, however, provide better drillability, lowerswab/surge pressures and facilitate better solids separation with zurface solidscontrol equipment. Low yield values (and low gel strengths) are desirable forgood mud removal when cementing casing (less than 10 is desirable).
B. Plastic Viscositv (PV)
In general the PV depends primarily on the solids content (size, type and concentration).
1. Plastic Viscositv High (PV) in Weighted Water-base Mud
Rule: PVn*: multipty MW (ppg) by 2 (to 2.5)
Formula: PVnier, = MW x 2.5
Example: What would be the high side for the PV in a 15 ppg mud?
Pvuor, = 15 x 2.5 :37.5 cps
2.
Rule: PV6*: multiply MW (ppg) by 2.5 (to 4)
Formula: PVorro : MW x 4
Exanple: What would be the high side for PV in a 15 ppg mud?
PVu* r , :15x4=60cps
3. Plastic Viscogiw (PV) for Water Base Muds by Weisht Ranges
Rule: Choose weight range and simply plug in MW (ppg) and completethe arithmetic.
Formula(s):
a. Mud Weights l-ess Than 14 ppg
1) PVn,o : (3.4 x MW) - 19
2) PV.,, : (2 x MW) - 14224
ttaIa)
,
aIa)
ttttIttItIttIt)
I,
t)
)
t,
,
)
tataIttt
II. MUD RELAIED RULES-OF-THI]MB (cont.)
B. Plastic Viscosity (PV) (cont.)
3. (cont.)
Formula(s): (cont.)
b. Mud Weights Greater Than 14 ppg but Less Than 17 ppg
1) Pvono = (5 x MW) - 40
2) PV'*, : (4.33 x MW) - 47
c. Mud Weights Greater Than t7 ppg but I-ess Than 18.4 ppg
1) Pvbis = (8.57 x MW) - 100
2) PV'o* = (8.57 x MW) - 118
d. Mud Weights Greater Than 18.4 ppg
1) P\,o = (16.67 x MW) - 249
2) PV,o* = (L6.67 x MW) - 267
Example: Estimate high and low ranges for PV in:
a. 13 ppg mud: PVr,,er, = (3.4 x 13) '19 :25
PVro* = (2x13) -14 :12
b. 15 ppg mud: PVu*r, : (5 x 15) - 40 : 35
PV6* : (4.33 x 15) - 47 : 18
4. Other Facts and Rules-of-Thumb About Plastic Viscosity (PV)
a. PV should be kept low as possible by maintaining low solids (particularly
minimizing fine solids ( 1 micron).b. PV is very temperanre sensitive and therefore should be reported at a
standard temperahre each time it is tested. If temperature isn't standardizedthe trend of PV, used to analyze hole problems, can't be used.
c. PV(cps) : 600 Reading - 300 Reading sa 3 penn Viscometer.d. PV is related to solids (type, size, and concentration).e. PV has a tremendous influence on cut poina in hydrocyclones and shaker
scre€n capacity.
2:5
!
IMurchison Drilline Schools. Inc.
tr. MIID RELATtsD RT LES-OF-TIII MB (cont.)
E. Solids
A general nrle is to keep solids as low as possible. Keep commercial solids (bentonite)and drill solids at a proper ratio. Solid can be better arullyzed if the mud MBT (MethyleneBlue TesQ is known. The MBT shows the bentonitic type solids. By knowing ttre tlpemud and all the retort analysis a breakdown of fine and coarse solids can be made. Finesolids (solids lgss rhan one micron) are twelve times more detrimental to rate of penetrationthan coarse solids and consequently should be kept at the required minimum to givecolloidal properties. The drill solids and bentonite ratio (ds/b) should be kept atapproximately 2 to L (2:l).
1. Optimum Percent Solids 0.,ow Density Solids)
Rule: Multiply the mud weight (ppg) by 7.5 and add the correction for oilby multiplying percent oil volume by 0.1. Subtract the correction forsalt. The salt correction can be estimated by multiplying ppm (CL by0.61 and dividing by 10,000. Subtract 62.5 from the corrected totalvalue.
Vol percent Solids (LDS) : [(7.5 x MW) +
(0.1 x vol. % oil) - 0'61 x PPM cLJl - 6z.s10.000
What is the estimated percent solids corrected for oil and salt.Given: MW = 9.0; CL : 20,000 ppm; Oil = 5%
Formula:
Example:
%r-Ds =[tt.txe.0) + (0.rxs) - l 'o'ut, l1f* ' l l - oz.s =4.3%L' \ loooo )l
Formula: LDS (#/bbl) : % LDS x 9.1
Exarnple: LDS (#/bbl) = 4.3 x 9.1= 40t
Oplimum Percent Solids (Weiehted Mud)
Rule: Subtract 6 from MW (ppg) and multiply by 3.2.
Formula: OPT Percent Solids : (MW-6) x3.2 (weighted mud)
Example: What is optimum percent solids in a 15 ppg mud.
(
(
I(
(
(
I(
I(
(
(
Ii(
(
II
2.
IIIIIIIIIIIIIIIIIIIIII
:
228
OPT Percent Solids - (15-6) 3.2 : 28.87o
Murchison Ihilline Schools. Inr2777772227ppr)
IDppTppppptIDI)
T,
II. MIJD RELATED RULES-OF-TIIUMB (cont.)
E. Solids
3. Rough Estimate for Percent Solids by Volume in Weighted Mud
Rule: Multiply MW (ppg) by 2
Formula: Percent Sol (weighted) : MW x 2
Example: Estimate percent solids in a 15 ppg mud.
%So l :15x2=30%
4. Drill Solids and Bentonite Ratio
Rule: Subtract the MBT from the total low density solids to get drillsolids. Divide the MBT Oentonitic type solids) into drill solids.
Forrtula: ds = TS - MBT
ds/b : ds
MBT
Total low density solids = 80 ppb
ds : 80 - 14 :66 ppb
66ds/b = = 4.7:l
A
(deal is 2:1)
Formula: Est. ds : GDs - MBT)
0.85
5. t*t1,uthe effect of solids on rate of penetration (ROP) comparing a controlwell with a planned well.
a. Rule: calculate fine solids on control well:
Mud Twes (General) Factors
"dffi'i'l#" = i:::$li3:i,Gel + ffrO + Polymer : Factor of 0.06
)
)
)
2
7?7I7IDtt
229
C
tr. ML]D RELAIED RULES-OF-THI MB (cont.)
E. Solids (cont.)
5. (cont.)
tIttttIItCttttJttttttIttt!tt!ttI!ttJT!tI
c .
d.
Fines are solids less than one micron. Coarses are solids greater thanone micron. To get fines multiply MBT by factor (based on mud type).Total solids = drill solids * colloidal solids + inert solids. Finesolids : MBT x factor; coarse solids : total solids - fines.
b. Calculate coarse solids on control well. Subtract fine solids fromtotal solids.
Cdculate fines and co:uses on ppposed we!!.
Plug in fines and coarses into the ROP formula for the control and oroposedwell (formula below) to calculate change in drillability (ROP).
Formula:
Fines
Coarses
Where: ROPM2
- (0.0133 F, +- (0.0133 F, +
: MBT x Factor
: Total Solids - Fines
= ROP on proposed well
: ROP on control well
l1ROPq = ROP*,
llL
o.oo114 c2)loro1l4Ql
ROPM
F2
F1
c2
cr
MBT
Fine solids (( 1 micron) on proposed well
Fine solids (< 1 micron) on control well
Coarse solids () 1 micron) on proposed well
Coarse solids () 1 micron) on control well
Methylene Blue Test
Example: Calculate the change in formation drillability (ROP increaseor decrease)
2:10
Murchison lhilline Sclools. InaJ',, II. MIjD RELATED RULES-OF-TIIIIMB (cont.)
, E. solids (cont.)a,A, 5. (cont.)
- ExamPle: (cont.)
Jt Given:) Control Well:
)
t ROPMr = 20 ft.lhr
I MBT : 15 lb/bbl
I ff{f :;,,?fJ't Mud Tlpe : Dispersed
-
I Proposed Well Mud Properties:
r ROPM - !
I MBT u
= 12 tb/bblt Sofids = 45 lb/bblf Mud Type = Polymer (non-dispersed)
I
' t\ :ffi:JI'6 5;i'?'(disn mud ractor) : l? iiiI 3) Fines (F) = 12 x 0'06 (polymer) = 0'72ppb
f 4) Coarses (C) : 45 - O-72 : 44.28 PPb
rJ'TtI,,
J')
)
f,,,
,ta)
2J')
r't
= 24.6 ft.ftr
Formula: For percent ROP reduction compared with water:
% ROP Reduction : 100 (0.0133 x Fines + 0.00114 x Coarses)
6. Analyze solids control equipment (and system) to ascertain it is doingan efficient job. By keeping up with water additions and by monitoringmud out and mud in, any break down in the solids control system can bedetected in the early stages.
Rule: Evaluate hydrocyclone desilters by cdculating: (1) GPM underflow;(2) barrels per day treated by bank of hydrocyclones; (3) pounds ofsolids dumped (discharged from underflow) per day; and (4) the amountof mud that would be required to be dumped (ened) to equate to solidsdischarged with hydrocyclones. Note: lais anellsis is simFle and canbe made more than once during a day to establish a trend comparison.The required data is: GPM underflow rate; underflow mud weight; andfeed mud weight.
2:Ll
5) ROPIq = m [1 : (O'-O-11?-I O'ZZ * O'OOtt+ * ++'Ze)
L 1 - (0.0133 x L2 + 0.00114 x 6'D
t
tr. MUD RELAIED RTJLES-OF-TIIIjMB (cont.)
E. Solids (cont.)
6. (cont.)Formula(s):(1) Cdculate GPM underflow (discharge) rate. This can be done by meazuring
the seconds for one Erart of discharge from one cyclone and multiplytimes the number of cyclones in the system.
GPM : (sec/qt)(number of cyclones)/l5
(2) Calculate the barrels per day underflow (discharge).
BPD : (GPMX34.29)
(3) Calculate the pounds of solids discharged by hydrocyclones.
Solids (lbs)Discharged
: (BPDX68.30XMW"-8.34)
(4) Calculate the volume of mud that would have to be dumped to equateto solids discharged by hydrocyclones.
Volume (bbl) _ (Solids Dischargedx2l.6cMwF)
ttttttIItttItIttttatMud Equivalent
Where: GPM =
Sec/qt =
No. of hydrocyclones =
BPD :
Solids Obl)Discharged =
Volume Obl)Mud Equivalent =
MWu =
MWF =
(909.72XMWF-8.34)
Total discharge from hydrocyclone system(gallons per minute)
Discharge from one hydrocyclone measured intoa viscosity cnp (seconds per quart)
Total number of hydrocyclones
Barrels per day of volune discharged fromhydrocyclones
Pounds ofsolids discharged per day throughhydrocyclones
The volume of mud that would be required tobe dumped to equal to solids dumped
Mud weight of underflow discharge, ppg
Mud weight of feed mud (system mud), ppg
tattattIIIItIIIaIIII
2:12
Murchison Drilline Schools. In,7IftFft77afDFftttFFftFfrftItFlrFpFI'DDbbbt
II. MLjD RELAIED RI]LES-OF-TIILJMB (cont.)
F. Mud Weieht (Density)
Rule: Maintain mud weight high enough to zupport the walls of the hole for holestability. Maintain mud weight high enough to avoid influx of forrrationfluids that cause 6ud sentamination, corrosion, kicks or blowouts.
Rule: Maintain mud weight low enough to permit faster drilling, avoid lostcirculation, and rninimize differential preszure sticking.
Rule: Approximately one barrel of volume is gained in the mud tanls when 15 sacksof barite is mixed (100 lb sack). The specific gravity of barite is approximately4.25 and this equates to approximately 1500 lbs per barrel.
G. Water Loss (Filtration)
Rule: Remember that low filtrate may be desired to minimize tight'hole caused by thickfilter cake, differential pressure sticking and formation productivity damage.However, high filtrate will minimize chip holddown and provide beuer drill-ability. This is particularly tnre if fine solids (< 1 micron) are minimized byrunning lower MBT's.
H. Shale Hydration and Dispersion
Rule: In surface or intermediate hole dispersion of clay and shale solids may be desiredin water-based muds for easier control of mud viscosity, gel strengths and filtra-tion without having to add commercial solids. However, inhibition of shaleswelling and prevention of dispersion of cunings by inhibition or encapsulationis desired for borehole stability, low mud maintenance costs, and protectionagainst formation productivity dnmage. The time to drill a section (open holeexposure) and problems associated with shale hydration, such as heaving shale,influence the mud prognrn. As a general rule short exposure (less than 7 days)won't cause many associated dri[ing problems to dispersion and shale hydration.On the other hand, longer exposure to dispersion and shale hydration can causesevere hole enlargement, poor cement jobs, hole cleaning problems and stuckpipe. Area knowledge is very important in the planning and optimization process.
t,
)
IttI)
tl
tt
2213
Murchisnn l)rillino Schools. Inc
tttrtttrltl'llIIt
Itr. TRIPPING RTJLES.OF.TIITJMB
Ideally, drilling people would like to keep bottomhole hydrostatic pressure constant during thetrip out (POH) and the trip in (RtrI). However, this is impossible from the operationalstandpoint because of swab and zurge pressures. Most of the tripping rules-of-thumb are closelyassociated with maintaining a safe hydrostatic overbalance that neither causes a kick nor lostcirculation.
A. Pnlling Out of Hole
1. Slug Mud Weight
Rule: Slug mud weight is generally one ppg higher then the hole mudweight with the objective being to unbalance the DP/annulusU-rube by enough to pull dry pipe. The condition of the mud,related to drill solids, and/or the mud weight range couldinfluence the drilling man to accept less than one pound pergallon. For example, if the mud weight was greater than 18 ppgor the mud had high solids, a 0.5 ppg slug mud weight would beacceptable. The length (or volume) would be double if the slugmud weight was 0.5 ppg compared to 1.0 ppg.
Example: The mud weighs 10 ppg; a slug of MW of 11 ppg is desired tounbalance the U-tube by t'wo stands (188 feet of top Dp).
Formula: Irngth of slugin DP
(Irngth of dry pipe) x (mud weighQ 0.052
(slug MW-hole MW) 0.052
= 188 feet x (10 x 0.052) : 1880
(11 ppg - 10 ppg) .052
: 1880 feet
(11 - 10)
Note: = The 0.052 should be left off; they were putin to make it clear.
Example: The mud weighs 18.0 ppg; a slug MW of 18.5 ppg is desired tounbalance the U-tube by one stand (94 feet of top DP).
Length : 94f t .x18
(18.5 - 18)
: 3384 feet
3:1
Murchison Drillinc Schools. Inc.
IIr.
A.
TRIPPING RITLES-OF-TIIIJMB (cont.)
Pulling Out of Hole (cont.)
2. Dry Pipe Versus Wet Pipe
When tripping the ptpe out of the hole the mud level falls in the annulus becausemetal volume is being removed from the hole. Pressure is lost because the fluidlevel is down and consequently the hydrostatic pressure is lower. The followingassumes the driller is not circulating across the wellhead:
Rule: Pulling wet prpe (no slug) €uses approximately four times morepressure loss, per increment of pipe, than pulling dry prpe (goodslug).
Formula: Dry Prpe Pressure [.oss :
Increment of oioe [ (nud gradienD (metal disp.) I
[(casing vol. - (metal dlsp.))l
rS/et Pipe Preszure [.oss :
Increment of pipe [(mud gradientXmetal disp. + DP cap.)l
[ (casing vol. - (met. disp. + dp cap.)) I
Example: Calculate pressure loss if five stands (94 ft/std) are POH. Thecasing size is 9-518 with 0.0732bbl|ft. volume capaclty; the mudis 15 ppg; the DP is 5n, 19.5 ppf, XlI, Grade "S" with an adjustedweight of 22.5 ppf and a capacity of 0.0170 bbl/ft.
a. Dry pioe:
AP=(5 = 46 psi
b: Wet pipe:
Ap=(5x94) = 192psi
I- l
(
IIITIIIIIIIIIIIIIaIIIi.l
IaaaaattaII!!a!a
lossDifference. wet PiPe APDry pipe AP
_ 192 psi46 psi
3:2
= 4.2 times more pressure
Murchison Drillins Schools. IncattIIItItttttttIIttIDItItI
rlrltItrlIIItItIIIII
m. TRIPPING RIILES-OF-TEIIMB (cont.)
A. Rrlling Out of Hole (cont.)
3. Metal Diqplacement
When ptpe is pulled out of the hole or nm in the hole volume of pipe metalhas to be considered in the trip plan.
Rule: Divide the adjusted weight of prpe (toot joints, collars, etc.taken into consideration for adjusted ut) by 2748 (weight ofsteel in pounds per barrel).
Fonu.rla: bbvft(metaldisp.) = ffi
Where: Adjusted weight : approximate weight of tube plus the upsets(tool joints) taken from RPTG @ages L3-L7) Aug. 1, 1990.
Example: Calculate the metal displacement in barrels per foot for 5",19.5, XII, Grade 'Su DP. The adjusted weight (approx. wt.) frompage 17 of RPTG is 22.6lblft.
bbuft =ffi=o.oo82bbvft
For five stands:
Volume Obl) : 5 std x 94 ft x 0.0082 bbvft
: 3.85 bbl per 5 stands
POH : hole would require this volume.RIH : hole should give up this volume.
4. Trip Margin
A trip margin is required when pulling out of the hole (POH) because ofnegative surge and swabbing.
Rule: (Refer to tr A 4., page 3:4)
3:3
m. (cont.)
A. Pulling Out of Hole (cont.)
4. Trip Margin (cont.)
Formula: ywl = Yield Point + Mwo"
(ppe) 11.7 (Dh-DJ
Where: MWr : Mud weight that includes trip margin
Mwb.r = -Mud weight to balance formation pressurebut bas no overbalance
Yield Point = Mud properry (300 reading (FJ - pV)
Dh = Diameter of hole
Dp : Diasreter of pipe
SWABBING IS CHARACIERUED
On Trips Whcn you carmot put a voluoe ofdrilliry fluid inro rhc hole equalto the displacemcnt of 6c pipcbcing rcmoved wirhout gaining fluid
Aftcr Trips Trrp gas or watcr or oil cutdriliqg fluids or a combination
;
I
(
(
(
ItIIIIIIIttI:
It!II(t
t
SWABBING ACTION
324
Murchison Drilline Schools. Inra2pp
)
)
)
)
I)
IIIIllrlttflDptII)
tItItIIIIIIIIIIDI
m.
A.
TRIPPING RULES-OF-TIII MB (cont.)
Pulling Out of Hole (cont.)
SWABBING MUST BE DETBCIED EARLY BECAUSE
Thc morc foroation fluid dlowcd to cfier,thc morc scvcre ttc kick.
The only way o dctcct swabbing h is eadysages is to accuratcly rncalrur€ thc amount ofdrilling fluid pumpcd in thc holc b replacethc drill pipc being rcnoved from 6e holc.
5. Tripping in Top Hole with Low Preszure Overbalance or Pulling Wet Pipe
Rule: When working with small pressure overbalances or whenpulling wet prpe mud should be circulated across thewellhead (out of trip tank and refirn to trip tank).
Formula: trngth of pipe then can be POH for the overbalance(trip margin) in the mud hydrostatic.
l - overbalance @si)
pressure loss per foot of pipe (*psiift)
Overbalance = Formationpressure-hydrostatic pressureMud Gradient = MW (ppg) x .052, in psi/ft
= (mud gradientxmet. dlspl)
(cas. vol-met. displ)
(mud gradient)(met. displ. + prpe cap.)
Where:
psi/ft(dry)
psi/ft :(wet) (cas. vol. - (met. displ. + pipe cap))
Note: Pipe capacity: see Chapter VI, Section D
3:5
Mnrchicnn Drillino Sclrrnls- fnc-
IIr.
A.
TRIPPING RLILES-OF-THI]MB (cont.)
Pulling Out of Hole (cont.)
5. (cont.)
Example: Calculate the length of prpe that could be POH (without circ across WH)if a 9.0 ppg mud was being used in a normally pressured formation (0.465psi/ft). The depth is 2,000 feet. DP is 5', 19.5 ppg, XlI, "E", (pulled dry).
aPob : t'H l":iffiJs2)'o'46st
L: 6ps i :110feet
* 9-518 casing (0.0732)
If more than 110 feet (a little more tlnn 1 stand) of pipe is POHbefore fi[ing hole a loss of hole stability will rezult. Thiscould include bridges @ole sloughing), stuck pipe, tight holewhich require back reaming and possible a flow.
Running Pipe in Hole
1. Surge Pressure
When induced lost circulation is analyzed closely, it is found to be closelyassociated with pipe movement and tripping practices a big percent of the time.By closely monitoring a metal displacement schedule, foruration break down fromsurge can be caught in the early stages.
When pipe is moved (up or down) surge and swab pressures develop. Velocityrate (fluid flow) is usually calculated to evaluate laminar or turbulent flow profilesand then pressure loss is calculated. Surge pressure can be approximated with thefollowing rule-of-thumb formula (rezults are usually a little low).
B.
3:6
Murchison Drillins Schools. Inr
m.
B.
TRIPPING RT LES-OF-THUMB (cont.)
Running Pioe in Hole (cont.)
1. Suree Pressure (cont.)
Rule: Calculate fluid friction (AP annulus) and add the preszurecreated by dynamic forces. This empirical formula is usedbecause it gives reasonable numbers.
PRESSURE STJRGES
Formula:
Fluid Friction * Dynamic Forces
P srrge = AP annuhrsx
Where: AP annulusx =I r .Y?
22s (E - d.)
lvfw3
. ( , , , .
dc '\
- l xdt - d"J
Ln 'w
22s (q - dJ
%MW
d.
dh
d,
L"
I,P
YP
maximum pipe velocity, ff/sec
mud density, lb/gal
collar diameter, inches
hole diameter, inches
pipe diameter, inches
length of collars, feet
length of pipe, feet
yield point, lb/100 ff327
-
Murchison Ihiltine Schools. Inc. I
Itr. TRIPPING RITLES-OF-THUMB (cont.)
B. Running Pige in Hole (cont.)
Example: Estimated $uge pressure given: 8-l/2, hole; 9,200 ft., 5n dp; 800 ft,6-L12" dc; MW 16 ppg; YV : 16; PV = 40; pipe velocity 2 fl/sec.
I tsoo x 10 e2oo x lot ID _lns vu2 4-u2)
- ns *-y2 - 5yl'srqgc -
|. .1 -
[r.o * = =!^-'P ==r r +l = r43 psiL rs-u2 - 6-LrD 3 I
EEriv. lvfW @ 10,000ft = ,==ll3=.Fi ^== + 16 = 16.3 ppg10,000 ft x .O52
3:8
Murchison Drillins Schools. Inc.2ItppItprtpttIttrttrtDDDDDDDrrDrt!tD!tDrtttIDIl'
DIrDrDrtDI
rV. CASING. CEMENTING AI{D PLUG SETTING
Casing and cementing, whether it be a primary or a secondary job, requires special emphasisbe placed on planning. The planning periods are: 1) items to plan and look at before reachingcasing point; 2) items to plan and look at after reaching casing point; 3) items to plan and lookat while running *hg; 4) items to plan and look at while circulating on bottom prior tocementing; 5) items to plan and look at while imFlementing the cement plan; and 6) items thathave to be looked at when secondary cementing (plugs, squeezes, etc.) are required. All checklist items and the list varies from one area of the world to another area. Some of the followingrules-of-thumb may be of use in implementing the various phases.
A. Circulating Time Before Cementing (Phase 4)
This is one of the most critical phases of the cementing operation. I have heardstatements like ttis, .the T.P. and I are going to have a quick brealdast and whenwe get back we will start the cementing operation. " Believe me folla-there is muchmore to this phase than how long brealdast takes.
Rule:
1. Circulate long enough to stabilizp hole trends zuch as drag,torque (if rotating), possible losses, etc.;
2. Circulate long enough to clean hole;
3. Circulate long enough to cool hole (this will minimize a lotof flash settlng because cement may not be designed for a long-static buildup temperanre);
4. Circulate at least the casing volume times t-112; and
5. Circulate at rate the cement will be mixed and displaced withto evaluate this rate.
Formulas: Circulating
Volume to circ: = 1.5 (Casing Cap. x Casing I*ngth)
Circulating rate = 1ann. vet. while drlg.) x (ann. vol.)
Volume to Circ Obt)urrculattng ume = _Circulating Rate ObVmin)
Note: Casing Capacrty in bbl/ftAnnular Volume of open hole in bbVft
4zl
7
Murchison lhillins Schools. Irc.
w.
B.
CASING. CEMENTING AND PLUG SETTING (cont.)
Influencing Factors or Why Casine Strines are Run (cont.)
Formulas: (cont.)
Run casing : Kick tolerance < 1 ppg (evaluate several kick sizesrefer to Chp. )ffv)
I-ast Casing Sening DepthNext Casing Point(2s% Rule)
Where:
0.25
AMW.b-s" = the change in mud weight caused by increasingformation pressure (or decreasing formation preszure)
Wro'o..qui". : foniution pressure is expressed as an eErivalent mudweight, i.e.:
), ppgTVD x .052
Mwr,. : mud weight at last casing shoe or before change information pressure, ppg
kick tolerance: the maximum kick MW that can be tolerated based on leakoff test at previous casing shoe
Example: Preszure is increasing. Shale densities, d'exponents, and resistivitymeasurement indicate the mud weight equivalent of the formation is16 ppg. The last casing was set in a 14 ppg environment, and theMW is now 15 ppg in the hole. Would you run casing based on the1-112 ppg rule?
Answer: Look at L.O.T. at last shoe and evaluate kick tolerance for severalkick sizes based on maximum allowable pressure (calculated fromleak-off test). The old l-ll2 ppg rule was used mostly before westarted testing shoes as we do today. Kick tolerance will be dis-cussed in Section )OV.
C. Mix Water for Cement
The cement quahty is very much dependent on the cement being mixed at the correctweight. Too much water affects compressive sfrengths; too little water affectspumpability; excessive water causes cement to have high porosity and permeability;free water causes pockets, hot spots and corrosion.
FP
(
(
I(
(
I(
(
l
4:4
Murchison Drilline Schools. Inc
IV. CASING. CEMENTING AND PLUG SETTING (cont.)
C. Mix Water for Cement (cont.)
Rule: Base mix water requirements on Deat cement plus the waterrequired for the admixes (gel, etc.). Use cement weight ascontrol on correct mix water being added.
Water requirements for neat cement:
Class Gel/Sack Slurr.v Density
15.6 ppg15.8 ppg16.4 ppg
For slurry weights other rhan the above, use the formula below, bearingin mind that additives zuch as bentonite or other materials may be requiredto compen^sate for excess free water. Rezultant compressive strength andsetting times will also be compromised.
Formula:
HrO for Neat Cemeal = (1.211 x ldXCement Wt. i-6)
Where ncement wt. " is the slurry weight, express in ppg.
Example:
Calculate mix water for neat L5.7 ppg cement.
H2O : (l.2ll x 1ffX15.73'6): 5.1 gallsack
D. Contact Time
Spacers are used to move mud out of the casing annulus, in front of cement, tominimize cement contamination and improve bonding. Much discussion has been givento cement placement technique (nrrbulent versus plug flow). The objective of placementtechnigue is to minimize contamination, channeling and lost circulation, and to maximizebonding and fill (correct cement top). With these objectives in mind I endorse thefollowing approach: place the spacer in nrbulence but keep the cement at sirme annularvelocity used while drilling.
Rule: Contact time is the time, that the preflush spaces in nrrbulent flow is incontact with a critical formation. Normally seven to ten minutes contact timeis required (750-1000 feet). Remember that the spacer must be compatibleat the mud interface, which muy times may require that two separatespa@rs be used, zuch as when using an oil mud.
4:5
'A 'o r 'B 'rGt
'H'
5.25.04.3
tsItFFptrtItrttrttrDr'ttttItt!ItDttl'
I
Murchison Drillins Schools. Inc.
rv.
D.
CASING. CEMENTING At{D PLUG SETTING (cont.)
Contact Time (cont.)
Formulas:
Example:
Spacer Volumeobl)
III(
(
I(
IIIIII
Annular Velocity =(ft./nin)
Pump Ouput (bbUnin)
Ann. Vol. Obvft)
Pump Ouput (BPM) = Ann Vel (ff/min) x Ann Vol (bbl/ft)(mix and displacement rate)
Spacer Fluid (bbt) = Contact Time x Mix Rate(to give reguired (nin) bbVmin
contact time)
How much spacer fluid is required to give a 7 minute contacttime? The mud in the hole is 9.5 ppg and the spacer is water.How much overbalance is lost from spacer if cement weightis ignored? The mix rate to give correct ann. vel. and putspacer in turbulence is 10 bpm. Ann Vol = 0.0679 bbUft.
= J min x 10 bbUmin
= 70 bbl required to give sevenminute "Contact Time'
: (MW6 - MW,p-o) 0.052 xlenglh spacer
IIIIIIaaqIaa
E.
APG{2o vs. Muo
- (9.5 - 8.33) 0.052 x 70 bbl
0.0679: 63 psi
Cement Plugs I-eavine Cementine Head
Plan plug dropping!! The correct use of cement plugs can make the differencebetween the zuccess or failure of a cement job. The correct implementation ofcement plug program raDks in the top ten of items tlnt affect the overall cement job.
Rule: Make sure you plan: the loading of the plug(s); who will drop theplugs; how the plug will be dropped (shutting down? on the run?); how youwill know if the plug has left the cementing head (radioactive nail andGeiger counter? Other telltale indicators?); what pressure strokes orvolume you will have when the plug is about to latrd in float orbaffle collar and; how much extra volume or pump strokes you willpump if the plug doesn't land. If no bottom plug is nrn contamination is1 % of volume of displacement. Therefore runexm cement or leave cementabove float collar.
IIaaaIIIaIIIaIaII
4:6
Murchison l)rillino Schools. Inc.attt,
tttttt)
t)
tItttt)
)
tt
DDrtrttrtttIttIItDIIII
IV. CASING. CEMENTING AllD PLUG SETTING (cont.)
Formulas:
Vol. to Bump Plug : (kngth of Casing) x (Casing Capacity)to landing place (bbVft)
, (ft)
iffr-iltf itffi-r - volume to bump plus (bbl)
*Pump Ouput :
*pump output Obustk)
Volume of trip tank Obl)Strokes to fill trip tank (stk) at full circ. pressure
Preszure to I^and Plug
APn,,dvsc'.r : (cement wt - mud wt) .052 x (calc.LrJ
TVhere:AP,*d/.,or = Calc. preszure to land plug (u-n$e preszure). If circ. pressure at
displacement rate is recorded prior to the cement job a dynamicpressure can be used (circ press * u-nrb press).
Calc. r ,,,o : kngth of cement that is planned behiDd casing (minus FS to shoelength if calculating bottom or one stage).
Est. Top of Cement @.") from &mod"scru
If AP is less then pre-calculated pressure
D,. = Est. ToP of Cmt .u &-'a"t't
AG.ua tr.*
If AP is greater than pre-calculated pressure
D.. : Fst. Top of Cmt - &'*d"'"o"
AGrua "r*
Where: D, : Depth of Top of Cement behind Casing
AG : (wt. of cmt - wt. of mud) .052 (ppg)
Example: Calculate the volume of mud and the pressure to land the top plug on thefirst stage; Given: Casing size 9-518", 47 lblf1 shoe @ 12,000 ft; FC @Lt,920 ft; DV collar @ 6000 ft; mud wt - 9.5 ppg; cement wt - 15.4 ppg;cement calculated to reach DV at 6000 ft; pump oulput checked to be 0.095bbVstroke.
4:7
virnrhicnn Drillinp Schools. Inc.
rv.
E.
CASING. CEMENTING AI\D PLUG SET'IING (cont.)
Cement Plugs Leaving Cementing Head (cont.)
Example: (cont.)
vol to bump plug : ll,92o (ft) x 0.0732 (bbvft)
= 872.5 bbl
Strokes to bump plug = 872.5 bbl
&-rdrr.m
Note:
0.095 bbl/s&
: 9185 strokes
: [(12,000 - 6000) - 80] x [(15.4 - 9.5) .052](ft)
: 1816 psi (u-nrbe)
If 800 psi circ press @ disp rate had been prerecorded, the dynamicpressure just prior to landing the plug would have been 2600 psi +(1816+ 800).
If the pressure to land the plug (above example) had been 200 psilow what would the estimated top of the cement be on the firststage?
;
I
I
I
I
(
I(
(
(
(
(
(
(
I(
I(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
(
Example:
D,. : 6000 ft + 200 psi
= 6652n 1 (15'a - 9'5) '052
F. Compressibilitv Volume When Testing Casing
The casing pressure test should be ploued (volume vs. preszure) as part of tbedrill out procedure. This compressibility plot can be utilized whenmeasuring the leak off vs. formation capability test below the casing.Interpretation of the leak off test is greatly enhanced if compressibility ispreplotted. Compressibility volume is required when evaluating bleed-backvolume to check if float eEripment and stage collars are holding.
Rule: In the water base muds it reqnires about 1% of casing volume (or volumebeing compressed) to reach 3000 psi. Oil is about twice ascompressible as water and therefore the compressible volume can beestimated by multiplying'the water based mud volume times the oilpercent factor (i.e., 10 percent oil = 1.10 as factor).
4:8
V"*
aaaaaaaaaatItttItttttttttttttta,
t,
aa)
a)
)
)
)
Murchison Drilline Schools. Inc
IV. CASING. CEMENTING AiID PLUG SETTING (cont.)
F. Compressibility Volume When Testine Casing (cont.)
Formulas:
Compressibility VolumeFor Waterbased Mudv* obl)
(pres applied @ zurface)(vol being compressed)
300,000
Compressibility volume : V.* x (1.0 * Percent oil,
For Mud with Oilv"" obl)
100
Example: How much volume would it take to pressure up to 2000 psi on 9-5/8", 47lb/ft casing? Assume no drill string is in the casing (open casing abovean FC @ t1,920).
_ (2000 psi) (11,920 x 0.0732)
300,000= 5.82 (say 6.0 bbl)
Examole: If the example above bad the same data except that the mud was aninvert oil emulsion with 70% orl, what would the V* (compressibilityvolume) be?
V- = 5.82 x(1.0 + 3100
9.9 bbl
25@
20@
l5@
lm
5@
oo 1 2 3 4 5 6 7 8 9 1 0
G. Safe Water Spacer for a Balanced Kick-off Plug
Kick-off plugs should have good compressibility to zuccessfully achieve the plugobjectives. Contamination of plug, with mud, will limit its compressibility (andusefulness). V[ater can act as a spacer fluid ahead and behind the plug @alanced).
Rule: The length of water that can be safely utilized should be based on overbalance(hydrostatic). The amount of overbalance that can be sacrificed and the differencebetween the weights of mud and water will determine the length (and volume) ofwater spacer.
429
t
CASING. CEMENTING AND PLUG SETTTNG (cont.)
Safe Water Spacer for a Balanced Kick-off plug (cont.)Formula:
I*.-ro* = allowable overbalance
(mud wt - 8.34) 0.052.Ope)
Volume water ahead = (I.,-*a*)(ann vol next to sening)ft string and hole bbuft
Volume water behind : (I*.-rp.*)Geuing string capaclty)ft bbl/ft
Example: flsy many feet of water spac€r (I*.* rpr""J can be used on thiskick offptug. Given: hole size 8-314 (calrper); dp (sening string)-4-tl2; dp cap - 0.0142 bbVft; mud - 14 ppg overbatance - 200 psi;overbalance that is allowable - 100 psi.
;
I
(
I
(
(
I(
(
(
(
(
(
(
I(
!IIIIIIIIaIaataaI
L**ro* = 100 psi
=::fo,j;'o' o"Volnme water ahead : 34O x 0.0547 = 18.6 bblVolume water = (340 ftX0.0142 bbuft)behind (to balancewater ahead)
= 4.g3 bbl
H. Things that Help Avoid Contamination of Kickoff plug
As previously dircussed the number one associated problem with kick off plugsis mud contamination.
Rule: Utilize techniques and equipment to minimize contaminating.
1. Use a mixine zub on bottom of sening string. Do not use openended pipe. A culled joint of drill prpe (with a good coDnection)can be orange-peeled on botlom and slotted. This zub can also beutilized for lost circulation plugs or pills.
2. Use a bylnss off of zurface cementing head. This bypass is keptclosed until cemeil starts out of setting string or until u-hrbereverses from having positive pressure to negative preszure (u-rubing). The blpass is then opened and the plug u-tubed into placeby keeping setting string full of displacemenr fluid. When the plugbalances, fluid will then come out the bypass line. This keeps youfrom overdisplacing and contaminating the plug. This step is thereal key to minimizing contamination of cement plug.
4:10
rv.
H.
aaaataatI'
Itttttttttttttt)
tt)
ttt)
tt)
)
ItD2Dbrtrt
CASING. CEMENTING AND PLUG SETTING (cont.)
Thines that Help Avoid Contamination of Kickoff Plug (cont.)
Exanrple:
3. Use viscous pills or dirty plugs to zupport off bottom cement plugs. Off-bouom plugs want to shift positions or migrate and this sffiing causescontamfuntion. Make sure viscous pill has x high yield value (yield poin|.A dtty plug is a few sacks of cement (10 to 15 sacks) that are displacedwithout any spacer. Cement contaminates and flocculates the mud. hrll theplpe a few feet above the dirty plug and set a proper balanced plug.
Formula:
Surface Preszuresetting string
(AP."'r) _ Vol. F.P. x (Mud wt-fluid wt) .052
(cap sening string)ObUft)
Where: AP*r : U-Tube Preszure caused by different weight fluids, psi
Vol".r. : Volume of fluid being pumped (i.e., HrO, cement, etc.)in barrels
Fluid wt. = Weight of fluid being pumped, ppg
,Y"'.'*aefr
What would the positive u-tube pressure be on the setting string if the settingstring had the lead HtO, cement and tail-in water. Given: 4-Il2 settingstring (0.Ot42 bbl/ft); mud wt. - 14 ppg; cement w - 16 ppg; lead HrO -
18.6 bbl; cement - 22.3 bbl of tail-in water - 4.8 bbl.
Lead Water Cement Tail-in-Water
AP,u: 18'6 x (14-8.33)0.052 + 22'3 x (14-16).052 *
4'8 x (14-8.33)'0520.0142 0.0142 0.0142
= 323 psi (AP surface pressure resulting from length of all fluidsin setting string (3218 feet) )
cementrng Head
4zll
Murchison Drilline Schools. Inc.
rv.
I .
CASING. CEMENTING AI{D PLUG SETTING (cont.)
Cement for First Cement Plue in a Irst Circulation Zone
When setting a cement plug for the first time in a zone for lost circulation, it isvery easy to underdesrgn the Enntity of cement needed. This will be a costlyerror because of rig time and material cost.
Rule: Until more knowledge about a zone is learned, a good rule-of-thumb is thevolume of cement the sening string will hold at the point of sening (bottomof sening string).
Formula:
Cement Required = kngth of setting x vol. of setting(cu ft) string (ft) string cu ft/ft
Example: llsv,r many cu ft of cement is required for the first plug in this zoneif the bottom of the setting string is placed at 6000 feet. Given:setting string is 5", 19.5 lb/ft, XlI, Grade 'E. (0.0983 cu ftlft)
Cement ReEdred(cu ft)
6000 ft x 0.0983 cu fl/ft590 cu ft
If yield (cu fl/sk) was 2.7 cu ff/sk (L.C. cm$
Sacks 590 cu ft. + 2.7 cu ff/sk219 sac*s
If mix HrO (gallsk) was 7.0 gallsk
Mix H,'0 = (219 sacks x 7.0 gal/sk) + 42 gaUbbl= 36.5 bbl of mix H,O
Note: If mix Hp is used as guide to mixing so many sacks out of a bigcement bin, it is very important to mix cement at its correct designweight.
42L2
Mrrrnhicnn T)rillino Snhnnls- fnn)
a-
?aa
aa,7!ItTDLIi
DI
FDIDItIt,,
ItIt,,
rtttt,trtD)
)
JD-
a)
-
a-
.aIt
rv.
J.
CASING. CEMENTING AIID PLUG SETTING (cont.)
Testing Liner and Squeezing Liner if Flow is observed
It is a dfficult task to isolate gas with a liner. Many techniques have been tried (and somework part of the time) but liner-lap leals is still one of the most prevalent gas-€pproblems. I recommend a high qualrty cement (barch-mixed if possible) and a longer linerlap (ISOO feeQ. Some operators cement the liner with a combination primary-secondarysqueeze approach. With this approach the liner is cemented partially (60-75%) usingconventional techniques and with a modified RTTS (Champ tool) the liner is squeezed afterthe primary job is completed.
Rule: When testirg a liner top use a reverse test and evaluate whether the liner top willflow into test string. Simulate a lower mud weight (approximately what the linertop will be exposed to) by using an RTTS (or similal tool). If squeezing isnecessary use a high quality (low water-loss) cement and use a walking squeezeapproach. Hesitation methods can be very misleading.
Formula:
r -4t20 -
Where:
(Mud Wt - Test MW Equivalent)Depth of Liner Top
(Mud Wt - 8.33)
Luo = Water to simulate some equivalent mud wt. at topof liner (in test string).
Note: If top of liner is given as TVD (directional wetl)the meazured depth can be calculated by dividingTVD by cosine of avg. drift angle.
Mud Weight : Mud weight in hole, ppg
Depth ofLiner Top : Feet (convert to measured depth to arrive at volume calculated)
AP.h".k (los x 0.052 x 8.33) + @epth Liner - Lrr2o)MW x .052
APd,".k x 19.23Equiv. M'W*o =
Depth Liner
Example: The hole contains 18.0 ppg mud and the top of the liner is 15,000 feet.How much water is required to be circulated into test string to simulate13.0 ppg (test equivalent mud weight)? (TVD and MD same.)
4:L3
7
Mnrehison Drillins Schools. Inc.(
(
IIIII
ry.
J.
CASING. CEMENTING AIYD PLUG SETTING (cont.)
Testing Liner and Sgueezing Liner if Flow is observed (cont.)
Lwo(18 - 13) 15,000
(18 - 8.33): 7.756 fe-r;t
Note: If the 15,000 foot depth was the TVD (directional well) with anaverage angle of 25o, the measured depth for volume calculationswould have been 16,551 feet or, 15,000/COS 25o. If the length ofHrO calculatd Q756 feet) had been at the same avg. angle (25'),the length of II2O would be 8558 ft., or 7,756|COS 25.
AP"h."& : Q,756 x0.052 x 8.33) + (15,000 -7,756)18x.052
: 10.140 psi
Eq'iv. Mw.ho.* - 1o'140 x 19'23
15,000
' 13 ppg
IIIIIIIIIIIaIIIIaaIItaIaIaIIIIaIIqqd
4z14
Daaarlaaaa)
)
t)
)
a)
)
t)
t
V. CEMENT
cement can be mixed with sand and gravel to build a pad with the following rules.
Rule: For a ratio of r:2:4 mrx, one cubic yard of blend can be designed withthe following formulas.
Cement = 4
rwSand = 6.28x2x0.035
Gravel :6 .28x4x0.035
Inches to yards = inches
E@-
Feet toyards = feet
@-cu ft to cu yd = cu ft x 0.0370 cu Yd
cuf t
Example: How meny an yards of cement blend (cmt, sand and graver) is neededto build a tool-pad with dimensions of 20 ft x r0 ft x 4 inches thick?(L) (w) (D)
Method l cuvd : $l * 4l * €l36 ntyd 3 fttyd @
= 2.47 sttyd
Method 2 cu yd = f1L x Z0 ft.x l0 ft)0.0370 cu ydl2lnlft *ft
2.47 cu yd
= 6.28 bags of cement
= 0.44 cu yd of sand= 1200 lb sand
= 0.88 cu yd of gravel= 1800 lb gravel
Requirements
Cement:Sand:Gravel:
6.28 bags x2.47 : 15.5 sacks0.!^ydx2.47 = 1.09 cu yd (2964 lbs)0.88 cu yd x 2.47 = 2.17 cu yO (,ga6 lbsi
5:1
Murchison Drinins Sclools. Inr2FpI)llttIlIltItrtrlr)Dr)tr}IIDDDDDtFptrtsDpptDt,
DttDt)
VI. VOLTJME AND CAPACTTY
Volume and capacity calorlations make up a high percentage of all rig calculations. Thefollowing rules-of-thrmb will simplify some of the arithmetic and the numbers (rezults) aregenerally acceptable.
A. Open Hole Volume
The rule-of-thumb gives approximately 3Vo more volume than the more precisemethod. Most open hole is a linle out-of-gauge which makes the methodacceptable.
RT]LE OF TET]MB FORHOLE VOLTJME
BBL/1000 31 = @)2
AI\D2
voLuME=(D)xL1000
SURFACE TO BIT TRAVEL TIME
-_(CorrLuJ*(Co"*La")Po,on* x SPM
Where:
Cap :
Co. :
Lde =
Ld. =p :'qrQut
SPM :
Rule:
Formula:
Capacity of Drillpipe ObVft)Capacrty of Drillcollars (bbl/ft)kngth of Drillpipe (feeQI-ength of Drillcollan (feet)Pump Ouput bbls/strokeStrokes per Minute
Square the hole size (inches) and divide by 1000 to convert to barrelsper foot. Multiply by lenglh (fee$ to get barrels.
r, _ @iameter of Hole)2voH=ffxkngth( f t )
Where: Vo" = Volume of open hole, barrels
Diameter of hole given in inches.6:1
Mrrctison lhilline Sc]ools,Ine-
VI. VOLUME AI{D CAPACITY (cont.)
A. Open Hole Volume (cont.)
Example: What is estimated volume of 1000 feet of l2-Ll4 inch hole?
Vot(L2.2r2 x 1000
1000
= 150 barrels
B. Estimating Hole Diameter from Lag Time
Rule: Calculate theoretical lag time. Measure acfiral lag time.Calculate lag time (difference (Ah). Calculate new open holesize from the lag difference (See formula's below).
Formula:ALt : ( IJ -Van/e)
IIIItIIICC!;
Ca!;
CC|F!atrfa;
It;
;
a|l;
;
T;
a|!!T!a;
aq
Where:ALt
dhl = ^l alr x Q x tozg.+ + Dh2\Lh
= Difference in lag time if hole is in-gauge (calculated)compared to actual lag time, min
IJt = Meazured lag time, minVan = Annular volume, bbla : Pump output (GPM|4?), bbl/minDhl : Calculated diameter of hole from lag time measurements, inDh : Diameter of hole drilled (bit size), inLh = Open hole length, ft
Example: Calculate open hole diameter from measure lag time.
Given:U - l lQ minVan = l2t& bbl (based on 12-114 hole)a : 13.33 bbl/minDh = 12.25 nLh = 4000 ft
6:2
ALt : (110 - 1218113.33) : 18.63 min
= 14.63 in
-
apI'rrta)JDI,,ar'r,Ir'r'r'rlr'rtttIIrttttIIIIIIIIII'ItaaTIt
\rI. VOLT ME AND CAPACITY (cont.)
C. Annular Volume in Open Hole
The rule-of-thumb will eive about 3% more apnular volume.
Annulus wirh Open Hole.
Rule: square the hole size (inches) and subtact the sErare of .the pipe size(inches). Divide by 1000 and multiply by length of hole secrion (feet.)
Formula:
. (Di - Dl x kneth (ft)AnnVolor=f f
Where: Dh and Do = Diameter of hole and diameter of pipe inopen hole, inches
Example: What is estimated volume of 1000 feet of annulus ifDu : l2-ll4 inches and % = 5 inches?
\ / _ (L2 .252 -52)x1000'oH -
looo
125 bbt
D. Volume of Vertical Cytindrical Tank
This formula gives accurate results for a cylindrical tank (vertical). Note: Do notuse for horizontal cylindrical tank (refer to Murchison Oper. Drlg. Manual - RigMath Chapter for horizontal tank calculation).
Rule: Square the diameter of the tank (feet) and multiply by factor 0.14.The results are in barels per foot.
6:3
Mrrrchicnn Drillino Schools- Inc.
VI. VOLIIME AND CAPACITY (cont.)
D. Volume of Vertical Cylindrical Tank (cont.)
Vol."yr.t"or : (Tank diameter)2 0.14
obuft) (ft)
How much water is in the tank if the diameter measures12 fe ,t and the height of fluid is 12 feet?
Voloou = (12)2 0.14 x 12 ft.
:242bbl
E. Capacitv of Pipe
This formula does not take into consideration tool joints and therefore over estimatesthe votrme by approximately 1.01 depending on what grade drillpipe is beingcalculated because high grade tool joints have smaller ID's).
RIG CAIft &a'*TIONS
1 -Area Calculations Formulae
CIRCLE:t= i .D2, ! t4
4 - 3.14151p2y z4
A = 0.7854 D2
HOLLOW CYUNDER:
A =o.r8ro fioop - rrop]
ntitJ
WRule: Square the ID of the pipe (inches) and either multiply by 0.097 to get bbl/100 ft
ol Ot 0.545 to get cu ff/100 ft.
Formula(s):
cap (bbl/100 ft) : ([D of pipe)2 0.097
cap (cu fl/100 ft) = (ID of pipe)2 0.545
I
(
(
(
I(
IIIIIIIIIIIIIIIIIIIIIIIIaaIIaIIaIII(
6:4
\rI. VOLUME AI\D CAPACITY (cont.)
E. Capacity of Pipe (cont.)
Example: What is the volume per
Note:
Grade EGrade XGrade GGrade S
capacrty (bbU100 ft) =
capacrty (cu ff/100 ft)= (4.276F 0.545
= 9.96
The exact volume for 5, 19.5, )CI drillpipe is:
100 feet if the ID of plpe is 4.276 inches?
(4.27q2 0.W7
1.77
:0.017464 bbUft= 0.0t7268 bbVft= 0.017176 bbuft: 0.017010 bbl/ft
F. Capacity of Annulus Betrveen Concentric Pipe Strings
The formula does not take into consideration upsets (tool joints) and therefore willbe off between 0.5Vo to 2%.
Rule: Sguare the ID (inches) of outer stringand zubtract the square of the OD (inches)of inner string. Multiply the rezults byeither the factor 0.097 for bbl/100 ft orby the factor 0.545 for cu ff/100 ft.
Forrrula:
cap (bb!100 ft) = @i - t,0.0e7
Where:
cap (cu ft/100 ft) = (D? - $ 0.54s
Dr = ID of outer string, inches
D2 = OD of inner string, inches
trt
6:5
Murchison Drillins Schools. Inc.
\rI. VOL(]ME AND CAPACITY (cont.)
F. Capacity of Annulus Benreen Concentric Pipe Strines (cont.)
Example: What is the annular capacity per 100 ft if the outside string is 4-112,10.5 lb/ft (ID = 4.052 inches) and inner string is 2-318 (OD : 2.375 inches)?
cap bbV100 ft) = (4.0522 - 23751 0.097= 1.M6
cap (cu ft/100 ft) : (4.0522 - 2.37*) 0.545: 5.87
G. Capacity of Annulus. Two Inner Strings in Casine
There is no allowance made for couplings and therefore calculations may be offbetrreen 0.5 to 2%.
Rule: Square the ID (inches) of the outer string and zubtract the OD's (inches) of innerstrings. Multiply the rezults by either 0.097 to get bbV100 ft or 0.545 to get cuff/100 ft.
Formula:
cap (bb[loo ft)=(Di - D? - oJ o.w
ro ofl- Ourcr -1
Snrp
WVAl,t/.1 l/zt)l . l t t / / . ' ll t / t l l f / l l
t ' / | t , / Al ' A L t / l
ooofInnet
Strirg
Where: Dl
D2
D3
Example:
626
cap (cu ft/100 ft) = (Dl - D: - o) o.s+s
ID of outer string of pipe, inches
OD of inner string of pipe, inches
OD of second inner string of pipe, inches
What is the annular capacity per 100 feet if the outside casing is7,29Iblft (ID : 6.1&t) and inner strings are : 2.375 inches OD?
cap @bl/100 ft)
cap (cu ft/100 ft)
= (6.IU2 - 23752 - 2.379) 0.097: 2.62
: (6.1842 - 23752 - 2.379) 0.545= 14.7O
l-- or -.]
Murchison Drillinc Schools. IncaJ.
tIIar'arDartIr'IttIrtrtr'rrrDIrDtttIItrDrlIIrDtItIIIIID
Vtr. HTDRATJLICS
Optimization in the dri[ing business is often defined as "collapsing the learning curve" whichmeans you post appraise daA from one or two wells and then drill the 3rd and remaining wellsmuch cheaper. Qptimi-ation could, therefore, be defined as cufting cost. The order ofop':mizatien with reference to cutting cost is: 1) optimize mud; 2) optimize hydraulics; 3)optimize bit selection; and 4) optimize weight on bit and RPM's. Mud and hydraulicoptimization, however, make the big money difference.
A. Optimum hydraulics is the proper balance of the hydraulic elements that willadequately clean the hole below the bit, clean the bit and clean the bore hole abovethe bit with minimum horsqnwer. The balance of the hydraulic elements isinfluenced by: 1) lost circulation @CD effect); 2) hole stability (arbulent erosion);3) bit slsaning (cross flow); 4) cleaning hole below bit (iet velocity) and cleaning thebore hole above bit (Ann. Velocity-Flowrate-yield value-and flow profile).
Rule: Balance flowrate between 24 gpm and 75 gpm (for optimum bitweight benveen 25-50 gpm/inch) per inch of bit size. Jet velocityis influenced by formation drillability and mud overbalance chiphold down. The grcater the overbalance the higher the jet velocityhas to be to help free up the chip that is being differentialty helddown below the bit. The jet velocity range is usually between 250and 450 fi/sec.
Formula(s):r
G/B =48*5
G =4B2+5B
Grio = L2'72 (B)r'47
ROP
0.01 + 0.002 (RoP)
IVhere: G/B = GPM/inch bit diameter
G = GPM (flowrate), gpm
G.i,, = For flowrate sensitive bits (PDC, erc.)
Ref. 1: World Oil, Review of l,ow Solids Mud Control Gives New Insights, D. B. Andersonand Jack Estes.
Ju
7zl
Mnrdrieon Driltinc Schools. Inc.
vII. HYDRALJLICS (cont.)
A. (cont.)
B : Bit diameter, inches
J" : Jet veloclty, tr:"
ROP : Penetration rate, fl/hr
Example : What is the gpm/inch mnge; the flowrate recommended; andrecommended jet velocity, to minimize chip hold down, bit ballingand give adeErate hole cleaning?Given: 12-114" bit; ROP 40 ft/hr.
G/B =4(12.25)+5
G
: 54 gpm/inch
: 4(12.2il2 + 5$2.25)
: 662 gpm
Q
0.01 + 0.002(0)
- 444 fllsec
B. Hydraulic Guidelines
Hydraulics can be optimized by concentrating on four main guidelines. The fourare: flowrate; jet horsepower; percent of horsepower at bit; and jet velocity.
Rules: The following guidelines are based on running optimum bit weight.
Rule 1: Maintain flowrate 30-50 gpm/in of bit diameter. The followingROP ranges are general guidelines for flowrates required.
ROP Ranges
Range 1 - over 50 ff/hr, 50 gpm/inRange 2 - 25 to 50 ft/hr, 40 to 50 gpm/inRange 3 - 15 to 25 ff/hr, 38 to 45 gpn/in.Range 4 - 10 to 15 ft/hr, 35 to 40 gpm/inRange 5 - 5 to 10 ft/hr, 30 to 39 gpm/in
J"
CaI;
!Iaaaa!JJaa!a!It!!!TJqqqqqq.l.lali.lqr{i
taI7:2
Murchison lhiline Schools. Intl'.FpFF?FFf.ftftItFftftItpftftftFtFFlDIttt!tI
I)DrtI'rtrDrtrDrltItrlrlIt
B.
VII. HTDRATJLICS
Hydraulic Guidelines (cont.)
Rule 2: Maintain jet horsepower 2-ll2 to 5 IIHP/if (hydraulic horsepower per sq inof bit area). The rule is based on the square root of the rate of penetration.In big hole (12-114 and greater size) the IIHP/it' could be allowed to gosligbtly above 5.0 (up to 6.5) if drillability is good (above 25 ftlhr).
Rule 3: Design hydraulics so that 50 to 65% of available pump pres$ue is across thebit jet nozzles. If optimized at midrange (55 to 60) the driller has moreflexibility with flowrate as influenced by formation drillability, ECD, andother dri[ing operational factors.
Rule 4: Maintain jet velocity betrreen 350 and 450 ff/sec. Do not drop below 250ff/sec. ROP and chip hold down influence optimum jet velocity as discussedin Section VII A.
Formulas:
Flowrate (Q) = Gpm/in range) x Bit OD
IIIP/{t- = /R-O:F: (no higher than f.J)
laaTiaz =(oebil)
1346(Bit OD)2
P* x 100
Pod
P o r r f = P t i r * P t *
P** : System pressure losses (surface connections,drill string and annulus - from boolc/sliderule/erc.)
D 1346(Bir OD)2/R6F'hc- - a
%Pr,. =
7:3
VII. HYDRAULICS (cont.)
B. Hydraulic Guidelines (cont.)
Formulas: (cont.)
(156.482XQ)2tvfWP =^&* l
el* t l+ !2+ets . )2
Average let Size
Jet Velocityadral =
I= 3.536 | a
\No. of Jets
(4183)(q)
Qzr* t l+J f+etc . )
Hr[
p - (MwX2)Qr't6[f o.se) .- sysrlo eoeo firff.J
Where:
aHH/in'?
R.O.P.
Poo
P*r
f1, f2, €tC.
MW
Poi p*
Pon..ort
L
PD
(Dh-DJ@i-p1L*
= Flowrate (gpm)
= Hydrautic horsepower per sq in of bit area
: Rate of penetration
= Pressure loss through bit nozzles
: Pressure required at surface
= Numerator only (i.e., t5132 = 15, t2132 : t2)
= Mud weight (lbieal)
= Pressure on bit calcglated when plenning, psi
: Preszure at bit calculated after selecting bit nozzles.
: I-ength (ft)
= Pipe inside diameter (in)
724
Murchison llrillino Schools. Inc.
tttttr'tIt
VII. ITYDRATJLICS
B. Hydraulic Guidelines (cont.)Where: (cont.)
Dh
De
Example:
: Diameter of hole (in)
= Outside diameter of prpe (in)
Plan and evaluate the basic four hydraulic elements. Given: bitsizrc: l2-ll4i; ROP = 25ftlbr:' lvfW = l0ppg; no. of jets:3.
Q : 45 gpm/in x L2-114"
: 551 gpm
t+D :rl2= ,/-zs
= 5.0
P."* : 1152 psi (from hydraulic book tables fordrill sfring and hole configuration)
D t346(L2.2rr{T5r bilroc
- 551
= 1832 psi
ret size = 3.5361g1 f-rg-y')"\ 3 \1832/ )
= 13.02(13) use 3 dze 13132 jets
D (156.482X5s1)2(10)'b,it*,-
(L3, _ n\ W
: 1848 psi (acural pressure @bit after sizing nozzles)
P.o,r : 1152 (system) + 1848 (bit): 3000 psi
725
tlurchison Drinine Schools. Inc.
VII. HYDRAULICS (cont.)
B. Hydraulic Guidelines (cont.)Formulas: (cont.)
2. IrH/itr
3. %Pon
4. Jet Vel
%P* 1848 x 1003000
= 61.6%
ruIP/d,h"r (ss1x1M8)
Jet Val =
13&(12.2r2
= 5.04
(418.3(s51)(132 +132 + t32)
= 454 fttsr*
Optimization Checks:
1. Flowrate = 55L1t2.25 : 45 gpm/in(30 - 50) opt. range
= 5.0 (OK)(2.5 - 5) opt. range
= 61.6% OK(50 - 65Vo) opt. range
= 454 fl/sec (OK)(350 - 450) opt. range
tatIataaaaaaaaa
C. Horsepower at Surface and Bit
Optimumhorsepower requirements are based onhole size and rate of penetration.
Rule: For iryut horsepower at surfac€, multiply 10 times the square of hole size(ten "D" rule). For hydraulic horsepower at bit, take the square root ofthe rate of penetration.
7:6
Murclison Ihilline Schools. IntIpFpFFPaFftftItftftFItttpttttItItttItItI'DfI'fDrtt
ItItItIt
It?ItplrIl)
VII. HYDRAI]LICS
C. Horsepower at Surface and Bit (cont.)
Formula(s):
HIIP-d = 10 (BitSize)2
HIIP/in2 = /mF:
Examole: Calculate the required zurface horsepower the rig should have available(influencing rig selection). Calculate hydraulic horsepower needed @ bitif ROP is 20 fl/hr:
HIrPoor ==*''u''
HIIP/in2 ==f
D. Roueh Neck Formula
The number one drilling parameter trend to monitor and evaluate potential hole stabilityproblems with is the pressure and pump stroke relationship.
Rule: Whenpump strokes are doubled the pump pressure will quadruple.This is because pressure loss inside a drill string increases as anexponeirtial function of the pumping rate.
/ SPIvL\2Formula: P" = P' l- |' L
\SPMr /
Where :P2 : hrmp pressure after changing pump strokes to new
level (SPM' - either up or down).
Pl = Pump pressure ttrat is associated with SPMt (originalpump pressure and strokes).
SPMI : Stroke per minute original (Pt assoc. with SPMt).
SPM2 : New pump strokes @r assoc. with SPMr).
727
VII. IIYDRAI]LICS (cont.)
Example 1: The pump pressure (P,) was 2500 psi with 80 strokes per minute (SPM').What would the preszure be if the pump strokes are raised to 85 (SPMTX
P, = 2500 rg)'' \80 /
= 2822 gsi
Example 2: In the sane example if the hole loaded up with formation cuning and SPM,dropped to 78 and the preszure remained at 2500 psi, how rnny psi can beattributed to the cuttings?
P. = 2500 F!\'- \80/
= 2377 w
Therefore:AP = 250[l' -2377 psi
: 123 psi due to cuttings
E. Effect of Pipe Size on Hydraulics
Because pressue loss inside a drilling string increases as an exponential function of thepumping rate, it is very important to choose drill string eEripment with large bores. Ifthis guideline is violated the hydraulic horsepower will be mostly lost before it reaches thebit nozzles.
Rule: The preszure loss in dritlpipe and drill collars shenges inverselyproportional to the change of bore diameter raised to the 4.82+ power.
Formula: APo..to = [ffi)-tt
4.82
Preszure loss with small prpe (psi)
Pressure loss with large pipe (psi)
Large diameter prpe (inch)
Small diameter pipe (inch)
IVhere: P2
Pr
Dr
D2728
Murchison Dri[ine Sc]ools. Int7FFpfrFItFpp!III'rtrtr'f,
f,
Drl)rtrtrta)f,
ftDrtfttr'rtrtDrttIt
VII. ITYDRAT LICS (cont.)
E. Effect of Pipe Size og Hydraulics (cont.)
Example: How much greater pressure loss does 4-L12, 16.6 (ID-3.826) havecompared to 5, 19.5 (1D4.276)? Pressure loss with 5' dp : 25 psi/1000 ft.
pttD
APg,* =(#)*'
: t.1L (I\e 4Ll2 drillpipe would lose 1.71 times morepreszure loss than the 5 inch drillpipe.)
pz = 25 (g\* = 43 psi' \3.826)
F. Effect of Mud Weight and Plastic Viscosity on H]'draulics
Pressure losses increase as the mud weight and plastic viscosity go up. Consequently it isimportant to maintain the mud weight and plastic viscosity at operationally safe low levels.
Rule: The presnre loss is directly proportional to the mud weight. Divide new mudweight by otd mud weight and multiply this number by the pressure losS meazured(or calculated) with old mud weight.
Formula(s):
Pressure hr,*.- = (eressne Inss with ̂*rr(ffi)
hessure h*** = (hessure Loss lvfw"""(#) t-
Where:
Pressne hr,rur.- = Pressure loss corrected for mud weight change
Pressure ho** = hessure loss corrected for plastic viscosity
(usually done in weighted muds)
MWr = Mud weight (original) corresponding topressure loss either all meazured orcalculated.
7:9
VII. IIYDRAL]LICS (cont.)
F. Eff""t of Mud w"ieht -d pl"rti" vi.*rity oo Hlndooti.r (cont.)MW2 = New mud weight. The pressure loss lvfW-n will
correspond 1e this mud wt.
MW : The mud weight that the mud had when the plasticviscosity was measured.
Example: Correct the pressrre loss in the system for mud weight changes andplastic viscosity. Given: Pneszure loss withMWr : 1000psi; MW,: 13 ppg; PV (with MW1 : 25 cps; new MW (MWr) = 14 ppg.
Pressure Loss MW =cor
= 1fi7 psi
(looo-(#)
PL.l- =22s(Db - DJ
LxYv LxPVV
hessue Loss PV"* = (rall *O(#)t"
= ll80 psi
G. Equivalent Circulating Densitv (ECD)
The equivalent circulating density (ECD) is the effecrive mud weight on rheformation due to the total effect of the mud weight plus the friction loss in theannular space betrreen the prpe and the hole while circulating.
Rule: The simplified version of the Bingham plastic equation givesa ryick ECD estimate. Multiply yield value times 0.1 anddivide by the hydraulic diameter (hole size minus pipe size).Add the results to the mud weight (lb/gal).
ECD=lv fw+ o '1 xYV
@o-DJ
LxYV
7:10
PLe- =22s(Dh - DJ 1500(Dh - DJt
Murchison Drilline Schools. Inc
Vtr. EYDRAIJLICS (cont.)
G. Equivalent Circulatine Dens8 (ECD) (cont.)
Formula(s) (cont.)
EO** = MW. -P.Lt(0.052 x Depth)
Where:ECD = Equivalent circulating density
Pr o,, : Pressure loss in annulus
MW = Mud weight (ppg)
W = Yield value (on Yield Point) lb/100 ff
Dh = Diameter of hole
PV = Plastic Viscosity
Dp : Diameter of plpe
L : Irngth (feeO
v = Annular velocity, feet per sec.
Example: Compare the estimated ECD with the formulas given. Given: MW :16.0 ppg; PV = 45; W : 25; Flowrate = 330 gpm; Ann. Vel* -
2.85 fl/sec; Ann. Vel* - 4.5 fi/sec; DP kn : 12,000 ft; DCI-en : 700 ft; DC OD : 6-112 inches; DP OD = 5 inchest Dn :8.5 inches
ECD=tO*.W =t6 .7pp|(8.5 - 5)
PLo- =W =4o3ps i22s(8.5 - s)
ECD*i" = 16 + .===!t ^== = 16.6t2,700 x .052
pL^__ - L2,0@x25 * 12,000x45x2.85 =465*e 225(8.5 - 5) 1500(8.5 _ ,2
7OO x 25 700 x 45 x 4.5L u L - - | - - 9 JN& 225(8.5 - 6.5) 1500(8.5 - 6.12
Total PLo- = 528
rt
7:Ll
VII. IIYDRAIILICS (cont.)
G. Equivalent Circulating Densi{v (ECD) (cont.)
Formula(s) (cont.)
ECDq,t" = 16 + 528 = 16.8 ppgI2,7N x .052
$rrmmary Comparison with 3 Methods : L6.7,16.6, and 16.8
H. Optimum Annular VelociW (From Fullerton)
Optimum annular velogity is influenced by mud weight aod hole size.
Rule: Divide the product of mud weight times hole diameter into11,800 to get annular velocity in feet per minute.
Formula: Ann. Vel. (ft/min) = 11,800(MW x D1)
Where: Ann Vel
Mw
Dh
Example:
= Optimum annular velocity in ff/min (by Fullerton)
= Mud weight (tb/gal)
= Diameter of hole, inches
What would the recommended annular velocity be for the 12-1i4 inchhole section with the following mud weights:Case 1 : 9.5 ppgll}-ll4 hole;Case 2 : 11.5 ppgll2-ll4 hole;Case 3 = 9.5 ppglS-ll2 hole?
Ann Vel (Case 11 = 11,800 = 101 ft/min
Ann Vel (Case 2) =
(r2.2s x 9.5)
11,800 = 84 ft/min(12.25 x 11.5)
' t=t'tT=. = 146 ft/min
(8.5 x 9.5)
7zl2
Ann Vel (Case 3) =
Murchison Drillins Schools. Inr
VIII. ESTIMATII{G HYDROSTATIC IIEN) PRESST'RE)
The basic hydrostatic formula to calculate pressure is used constantly in the dritling business.The formula is rearranged to also calculate mud weight and even depth. Before introducing therule a few concepts will make the formula clear.
Concepts: Two concepts will be introduced:
Weight of a column of fluid and:Preszure in a column of fluid and preszure eradient.
Now. what is the pressure. in psi. at the bottom of a 5000 ft stack of 1 cu ft cubes?
Total weight = 486,200 lb
Base area : L2 x 12 sq ins : 144 sq in
so: P (psi) - 486'200 -lb = 3376 psiLU nz
Consider a 13 ppg nud. How much does I ff of this 6ud weigh?97.24 bs
/-a MW' = 13 ppg = (13) g.aS) pcf
Tfl | =e7.upcf =e7.241blcuft
'^1134.*F- ( 'n
lcu f t =144sq inI t t
Now consider 5000 zuch blocks stacked vertically.
*,1 fl
rota,weight=.gJ:,:A6-'oor
-1]J4862@bs
,
7FFtFF.777FF.FFFpFftItItppItftItlttI'I'I'I'r'I'I'II'taa,a,trtttt
8:1
llrrchison Drilline Schmls. Inc.
vltr. ESTIMATING FYDROSTATIC IIEAD (PRESSITRE) (cont.)
Now, how much does 1 i..tr of 13 ppg mud weigh?
lvfW = y!+ = 0.056271b/cu int728
How many 1 inch cubes stacked up make 5000 ft?
Number = (5000) (12) -- 60,000 cubes
Total weight : (60,000(0.05627): 3376 lbs.
T=lI,lllI t l'*nlllllltlItlJLLJ4
F-tfl in
Now. What is the preszure in psi at the bottom of this mud coluurn?
Base area : 1 sq in and weighted above : 3376 lbs
So: h 3376 lb ^^P = l - ' - : - = 3376 Ps irsqm
From this we see that, although the cross-sectional area of the mud columnsare different, the pressure at the bottom of the columns is the same! Thepressure at any point in a mud column depends only on the tnre vertical depth(TVD), not on the area or the shape of the column.
Oll0'.
- l @ t l476 F
- @ l l20i2l*
- grDt3:t?6 F
822
(cont.)
It rurns out that we have a simple formula that will predict the preszure at any depth. It is:
PSI : 0.052 (Mw) (ft.)
The units are : 0'052 gal x lb x ft : lb= DSI
oft
I t
otri
0.676 p.i
1352 Ft
2.O28 psi
2.7Oc p.l
3.38ri
.l Ps 0.676 Fi
J P:0.676 93i
J P: 0.676 9nl
J P: 0.676 Fi
I P-- 0.676 Fi
!-,
.)
rta,a)f)
taaaaaaatt
2fr
3ft
at r
5ft
Rule:
ft sq in gal sqm
Example:
PSI : (0.052) (13 ppg) (3000 ft) = 2028 psi
Know this formula! You will use it all the timd. with the above formula we can findthe preszure at any depth with:
PSI : (0.052) (13 ppg) (ft) vatid for 13 ppg mudconstant tenn
You need only to compute the constant tenn once. It is:
(0.052) (13) = 0.676 psi/ft
This number is special and is called the pressure sradient for 13 ppg mud. It tells ushow much the mud pressure changes roi.-.n roo@th, so:
To help remember the basic formula to calculate pressure multiply thenumber of weeks in a year by the mud weight in pounds p"t i"ttoo.Multiply this product by true vertical depth in-ttrousanas of feet.
PSI : lvfW x (No. of weels in a year) x TVD
8:3
Formula:
Mrrrhis.rn Drillino Schools. Inc-
\rltr. ESTIMATD{G EYDROSTATIC IIEAD (PRESSURE) (cont.)
Where: PSI
IvIW
Pressure at some depth
Mud weight in pounds per gallon
TVD : Tnre vertical depth, in thousands of feet
No. of weeks in year = 52
Note: The 0.052 units are anived at this way:
7 .48 gallcu ft. 7.48 gal sq ft
Example:
144 sq in/sq ft cu ft 144 sq in
= 0.052 gal
f tsq in
)What is the hydrostatic head (preszure)contains 13 ppg mud?
PSI=13x52x5
at 5000 feet if the hole
: 3380 psi
8:4
The approximate strength of steel cable can be estimated in tons by the following rule'
Rule: 1. Change line dianeter to eights'2. Square the ntrmerator.3. Divide bY the denominator'4. Read the tnswer in tons.
Example: What is the approximate strength of 3l4 inch steel cable?
1. Diameter = 1io"n=9io"h48
^ & _36L. T'T
3.36+8:4 .5
4. Answer = 4.5 tons
9: l
ffi Rdes of rhumb Notebook, world oil, Gulf Publishing co. - L967.
The approximate strength of manih rope can be estimated in pounds by the following rule.
Rule: The worki4g strenglh of manila rope is approximately equal to 900 times thediameter sEnred. If rope diameter is greater thzn 2 inches, a factor lower than900 should be used. In workiqg with heavier rigging, accepted handbooks shouldbe used to find safe working strength.
Formula:
Where:
Working Strength = 900 x D2
D : Diameter of rope, inches
What is the estimated working strenglh of 112 inch manila rope?
Working strenglh : 900 x (0.5)2
Example:
= 225lbs
Ref. 3: Production Rules of Thumb Notebook, World Oil, Gulf Pnblishing Co. - L967.
10:1
rtrtrtrfrttrltIrDa)rlIIrlIIt
When line ptpe is made up (screwed together), there is a loss in length at each joinr. This make-up loss can be calculated by the following rule.
Rule: For ptpe sizes 3-inches in diameter and larger, which have standard 8-threads perinch, the following formulas may be used to determine pipe make-up loss.
Formula(s):
Where:
Note:
Correction in percentage : 0.57 + (0.04) D
Correction in feet 1rr mile : 30.1 + (2.11) D
Correction in inches per 1000 feet : 68.4 + (4.80) D
D : Nominal diameter in inches
Example:
These rules (estimates) are adequate for standard-weight pipe.However, there is some variation in larger sizes of prpe andfor extra heavy and very light weight tubes.
How much extra pipe should be ordered to make up for screw lossin a 5 inch rig water line.
Vo=0.57+0 .04x5=0.77%
ff/mile : 30.L +.2.11 x 5 = 40.65 fi/mile
inches/1000 ft : 68.4 + 4.8 x 5 = 92.4 ins/1000 ft
Ref. 4: Production Rules of Thumb Notebook, World Oil, Gulf Publishing Co. - t967.
11:1
)
J.Mur,chison lhillinesdools.Ine
r, )ilr. CENTRTFT'GAL PIIMPSS
I The main factors influencing rating of centrifugal pumps are impeller diameter and operatingI RPM's. These two variables influence head (infeet), output capaclty (inGPM) and horsepower.
ft Some of the nrles are listed below.
rtIaaJ.,DAD,aI'
A. Head in feet varies in proportion to the square of the speed@PM's). The higher the speed, the higher the head. Head in feetvaries in proportion to the sguare of impeller diameter. Thebigger the diameter, the higher the head in feet.
B. Capacitv (GPM) varies in direct proportion to the speed. Thehigher the speed, the higher the capacity. Capacity varies in directproportion to impeller diameter.
C. Horsepower varies in proportion to the cube of impeller diameter.Horsepower varies in proportion to the cube of the speed.
Formulas:
/RPlvL\2H*4 (ft) = Head, | 'l
\ruMtr
H*4 (ft) = Head, BI
/RPtvL\GPIVL = GPM, | 'l
' l .RMt /
cPM, = *",[*)
/RPlvL\3HP^ = HP. | ' l
z L \PMt /
Pto*.r.-. = 75It x 0.052 x MW (PPg)
R"fJ Pr"du.ti"" Rrles-of-Thumb Notebook, World Oil, Gulf Publishing Co. ' 1967
HP, = *,(*l
L2zl
6)ilI. CENTRIFIJGAL PUMPSS (cont.)
d
Where: qHead, : Calculate new feet of head w/ either RPM or impetlet Cl
diameter changed ;
GPI\[ : Calculate new capacity (GPM) with cbange in RPM or impeller 7diameter change q
aIIP2 :
:#*:.ffiry with change in RPM's s1 impeller I
dPoror*"o* = The preszure on the hydrocyclone manifold if the head is Il
kept constant at 75 feet dcExample 1: Calculate: thechangeinHead(Head);changeincapacity(GPMJ; A
change in horsepower (lIP). Given: HP1 : 25; GPM, : 400; aHeadt : 170 feet; Dt = 7 inch; RPMt = 1450. Changes: JDz=8in . ;RPMr:1750. Iq
qH*4:#ll]vRPM,sarechanged)
;;q
H*4
:"*l *only impener diaurete, is shansed) :
Iq4GPM':k^il""rRPM'sarechanged)
;
IGPM'
:H (if only impeller diameter is changed) ;
IHP2
:;flonry impe[erdiameter is changed, J
i'\222
1
Murchison Drillins Schmls. IncIFFFFFrFFr.FFFftFftpFItItItItDa,.)
T'I'ft,)
ftD,)
D,)
a,t,tI'Irtf)
Example 1: (cont.)
HP2 = '' (+#3),
= 44 (tf only RPM's are changed)
Example 2: How much pressure should you have on the hydrocyclone if 9.5 ppgmud is being used?
P:75 f t x0 .052x9 .5
37 psi
L2z3
Murct onlhillineschools. Inr
)iltr. BOP ACCUMULATORS
Usable hydraulic fluid, to operate the blow out preventer equipment, is affected by accumulatorprcssure and nitrogen precharge. The following rules apply to sizing accumulator (volumerequired for nitrogen and hydraulic fluO and for running a quick check on average nitrogenprecbarge of system (without having to drain hydraulic fluid back into accumulator storagereservoir and individually check each bottle, which is time consuming).
Rule 1: If the nitrogen precharge is at the correct (recornmended) precharge multiply the sizingfactor (see below) times the fluid reErired to operate a qpecified number of BOPfunctions to arrive at reqtrired total accumulator volume.
AccumulatorOpcntingPressure
MinimumRecommendedPrecharge UseablePressure Fluid
AccumulaorSize
Factor*
8J
2
r/8u3tn
75010001000
150020003000
*Based on minimum discbarge pressure of 1200 psi.
Eottha
MlnimumDischargc
Pre6s
Rule 2: A quick check caD be made on the average nitrogen precharge of the complete BOPaccumulator system with the following steps.
Note: Pipe out of the hole and blind ram blosed and locked.
1. Read accumulator pressure (i.e., 3000 psi),2. Close off hydraulic line going to air and electric accumulator pumps.3. Pick up test joint and position in BOP's. Operate one or more of BOP functions
(i.e., closed hydril and opened Type F valve).4. Read new manifold pressure (now drawdown because of operating BOPE, i.e.,
1800 psi.5. Calculate fluid required to oPerate BOP functions (i.e. ,29.94 gal).6. Calculate average nitrogen precharge of accumulator system.
Bdtl€tl
Prcchargc
tII
13:1
ri?chif.rn Drillino Schools. Inc.
)iltr. BOP ACCUMULATORS (cont.)
Formula(s): (cont.)
Accumulator hessureNitrogen Precbarge (Acqm-Press.
Vr:Vox2
ny _ (Vol. Removed)(Starting Accum. Press.XFinal Accum- Press.)-
\d (V1)(Starting - Final Accum. Pressure)
Where:
Vr = Total hydraulic fluid and nitrogen to base accumulator volume sizing on
Vd : Volume required to operate BOPE that accumulator sizing will be based on
Accum. Press.: Pressure rating of accumulator system (or operating preszure)
NitrogenPrecharge : Should be 1000 psi for 2000 and 3000 psi system. It should be 750 psi
for a 1500 psi accumulator system
Minimum DischargePressure = This is the recommeadsd minimum discharge pressure to base design on
(200 psi above nitrogen precharge)
P" : The average nitrogen precharge in system (calculated after operatingBOPE and measuring drawdown)
Example 1: Calculate the required accumulator system if the design was based onoperating the following BOPE and having 50% SF; 3000 psi accumulator.
Vr=Vox tGal)
L
Minimum Discharge Pressurc |cum-Press. - MiL Disch. ness.)l
1, Hydril, GK, 13-5/8, 10,000 psi (bag)2, CIW, Type "U', 13-5/8, 10,000 psi (ram)1, CIW, Type "F", 4', 10,000 psi (hydv.)
50% ReserveTotal (Hydraulic Fluid)
Close Ooen
29.35 20.96l l .6 10.900.59 0.59
37l1l gal
(111 gal) t'*o n"lt tt* -)
1000 psi (3000 - 1200)
13z2
vr:
7?ftftItpItItPPttttftIttrItItItttItFtItItFbftttI'FttFtsDFFtFt2ablttFFF
Murshison Drilline Sc.hools. In
)iltr. BOP ACCUMT LATORS (cont.)
Example 1: (cont.)
: (111 gal) (2)*: 222 gal (nitrogen * hydraulic fluid)
*Note: The sizing factor comes from the pressure side of the above equation.
Example 2: Using the above accumulator system (?22 gallSffiOpsi). Catcutate the average nitrogen precharge inthe system after the system bad been in use severaldays. Given: (from steps in Rule 2): drawdownpressure = 1800 psi after removing 29.94 gal ofhydraulic fluid (operated hydril and Type F chokevalve).
D _ (29.94X3000X1800)-a
Q22)(3W - lS00)
= ffi1 psi (average nitrogen precharge inaccumulator system)
Note: This system should have 1000 psi nitrogen precharge, and thislower precharge pressure lowers the amount of usable fluid that isavailable to operate the BOPE. To find out which bottle(s) arelow in nitrogen precharge the hydraulic fluid has to be drainedback into accumulator storage reservoir and each bottle checkedwith a pressure gauge. Use clean nitrogen to pressure the bottlesback to 1000 psi.
13:3
Murchison Drilli ns Schools. IncIF
FFItpFftftFFFFthtFFpFDFIFFfclclDlclclclclcl.Itpl.pptpl.l.rtI
)ilV. KICK TOLERAIVCE
By utilizing known rig data and a series of formulas (in which part are rules-of-thumb) kicktolerance can be calculated for several nwhat-if" sinrations. A leakoff test sometimes leads tofalse security unless the size kick is considered. Kick size greatly affects control capability andin fact it is the number one limitation to control capability. The size kick a drilling crew allowsis a direct reflection of motivation and well control awareness of rig personnel and places a highpriority on rig-selection. When kick tolerance, based on a realistic kick size, is calculated tobe below one pound per gallon (1 ppg) an operator may consider running casing to prevent lostcirulation (the greatest associated problem to well control).
Rule: To evaluate kick tolerance choose two or tbree hlpothetical (redistic) pit gninsand: calculate DC annular volume (formulas); evaluate whether the kick is largeenough to cover the drill collars and part of the drill pipe or not--after makingthis determination use either formula 7 or formula 6 to calculate length of influx;calculate estimated shut in casing pressure (formula 8); calculate maximumallowable pressure (formula 1); calculate bottom hole pressure maximumallowable (formula 2); calculate bottom hole preszure maximum mud weightequivalent (formula 3); and calculate kick tolerance (formula 4). Make decisionabout the safety of drilling operation related to well control (taking a kick thatwould break the formation down somewhere in open hole).
Formula(s):
1. Max Allo Press = (L.O.T. - MW) .052x Shoe TVD
2. BIIP Max : ((TVD - Len InFx)(.052XMW) + (Max Allo P) + (Irngth Influx x 0.1))
3. BHP MWE = BHP MAX
TVD - .052
4. Kick Tolerance : (EIIIPMWE - MW)
5. Dc Ann vol. : ((Bit size 2 - DCoD2) Dc kn )1000
rrn rnnx*A_ = ,nt,:11; T 9?J::, t* + DC rrn)
@itS ize2-DPOD2)
I ."nlnflx*A-,:g@it Size2 - DCOD2)
SICP : (SIDPP + Itn Influx (Mudgrad - Influx Grad))
Equiv MW Shoe : 6Hole Mw + SICP \0.052 x Shoe TVD
7.
8 .
9 .
10. Shoe Pressure - (Form Press - (Hydrostatic Preszure below Shoe))
L4tL
Lfrmhknn D'rillino Schrnls^ fnc-
)ilV. KICK TOLERANCE (cont.)
Where:
Max Allo Press
L.O.T.
MW
Shoe T\lD
BHP Max
TVD
Irn Infl
Max Allo P
BIIP MSTE
KickTolerance
DC Ann Vol
Bit Size
DC Size
DC kn
kn Inflx**,
kn Inflxo.*,
SICP
Mud Grad
Infux Grad
Equiv. MW Shoe
Shoe Preszure
Form Press
= Maximum Allowable preszure, psi
: Leak off test mud weight, ppg
= Mud weight in hole, ppg
= Tnrc vertical depth of shoe, ft
= Bottom hole pressure maximum (a partial step inkick tolerance calculation), psi
: True vertical depth (TD), ft
: I:ngfh of influx, ft
= Maximum allowable pressure based on leak offtest at shoe, psi
= Bottom hole pressure mud weight equivalent(partial calculation in kick tolerance program), ppg
= The maximun kick intensity (kill wt.) that can betaken for the size (pit gain) kick and theL.O.T. calculated, ppg
: Drill collar annular volume, bbl
= Bit outside diameter in inches, in
: Drill collar OD, in
: Drill collar length, ft
: I*nglh of influx in drill plpe and dc annulus, ft
: kngth of influx in drill collar annulus, ft
= Shut in casing pressure, psi
= Mud gradient (MW x 0.052), psi/ft
= Influx gradient (assumed to be 0.1 psi/ft), psi/ft
= Equivalent mud weigbt at shoe based on shut incasing pressure, ppg
= Preszure applied to a casing shoe, psi
: Formation pressure (hydrostatic preszure *SIDPP), psi
l4:2
) Murchison Drillinp Schools. Inr,a)
,)
ttt,,,
-
ta)
)ilV. KICK TOLERANCE (cont.)
Example 1: Calculate the kick tolerance for a26 barrel kick.
Given:
ItrttDlltDDItItItDDaDD!tlf)
rtDDrtDDaIIDIDl'
Bit OD - 8.5 inchesDC OD - 6.5 inchesDP OD - 5.0 inchesDC Irn - 720 feetPit Gain - 26 banelsTVD Shoe - 8,000 feetT\ID TD - 12,500 feetMW Hole - 14 ppgMW L.O.T. - 16.7 ppgSIDPP - 650 psi
'o 52 - 6s)(720)DC Ann Vol =\o"1000
: 21.60 bbl
Size Kick = 26 bbl; therefore part of the kick is abovedrill collars
Q6 - 2t.6',) rc40 + 72Okn ln f l x *Ann : . . . , . . , *
= 813 feet
SICP = 650 psi * 813 (14 x .052 - 0.1)
: 1161 osi
Equiv. MW Shoe = to * 1161 Psi(0.052 x 8000)
= 16.8 pp8
Max Allo Press : (16.7 - 14) .052 x 8000 ft
= 1123 osi
BHP Max : (12,500-813)(0.05XMW)+(1123)+(813 x 0.1)= 9713 psi
BI{P MwE : 9713
12,500 x .052
= 14.9 ppg
L4:3
Murchison lhitlins Schools. Inc.
)ilV. KICK TOLERANCE (cont.)
Example 1: (cont.)
Comparing a 10 bbl kick with the above 26 bbl kick.
Size I*ngthKick Influx SICD SIDPP
l0 333 826 65026 813 1161 650
MaximumAllowable
tL23It23
BHPMax .
10,0149,713
BHPMWE
15.414.9
KickTolerance
1 . 40 .9
*Norc: A l0 bbl kick could be taken but a 26 bbl would probably break the shoe down.
14:4
Murchison Dri[ins Schools. Inr
XV: WATER IIAMMER EFTECT
A well that is flowing with great intensity (hrgh flowrate) can cause higb hammer force whichmay damage BOPE or wellhead. However, most kicks that are detected early and tbat are nottoo much underbalanced (< 1.5 ppg kick intensity) will have only minimum hammsl effect onequipment. The once recommended soft closure to minimize the water hemmer effect has lostsome of ia popularity and many operators are recommending bard clozures to minimize l6is1size. Kick size has the greatest effect on kick control capability. The maximum rate of clozureto prevent most of the hammer effect depends on how fast the.clozure pressure wave travelsthrough the mud and the well depth. If the qpeed of sound in mud is taken to be 1000 fi/secthen the round trip time for the clozure pressure wave is:
h' z \ 2 x Measured Depth = 20 sec in the example belowIlme (sec) = ------
If the well is closed in (less than 20 seconds) then the chance for a severe hanmer is high. Forshallow kicks this time is greatly reduced.
Rule: Calculate the hammer pressure utitizing the annular velocity and mud weight andmultiply this times the cross-sectional area of pressure exposure.
Formulas:
| | \APo" .. =
[fiJf***uelocity)(/ilffi)
APo*o = (APb@J@OP SiZe2-DPOD2XO.Z8S+)
Where:AP*o-,o.,' & AF -*,
Ann. Vel : Annular velocity in feet per minute
MW : Mud weight (ppg)
BOP Size = ID of BOP's (inches)
DPOD : Drillpipe outside diameter (inches)
= Preszure and force created from rapid closure in awater base mud. Note: oil muds are more compres-sible and therefore have less hammer effect.)
15: l
vilrclrieon Drillins Sclools. Inc.
XV: \MATER HAMMER EFTECT (cont.)7777Ie4
1e1e1a4ad
7114qclf1qqq
7f4c{G{qalqqqde1q
Bring Kick !o a 'Halt* Gradudtyto Prevent Shocking Formation and BOPE
Given:
BOPE DiameterHole SizeDrillpipe DiameterAnn Cap Around dpMWFlow RateWell DepthAnnular Velocity
: 13-518= 8-ll2' below 9-518 casing 47 lblft=5u: .Ot9 bbUft= 13 ppg: 20 bbVminute= 10,000 feet= 20 bblimin = 408.2 Sm
.049
So:
tlammer (&8.D{E = 541 psi
Hammer = 54L (.7854X13.6252-5\ = 68,256 lbs
1= -2.72
or
L5z2
This hammer force will be exerted on the wellhead for a few seconds.
,
FFFpFt,FtftItFpppFFFFfD|eFFFlD|IpFppppl.ItItpppf.tIrt
Murchison Drillins Schools. Inc
XVI. SIIALES
Shales cause hole and dri[ing problems when they lack or lose stability. Shales lose stabilitybecause of: 1) hydration; 2) surge and swabbing; 3) hydrostatic underbalanced conditionsrelated to tectonic forces and/or compaction (de-watering) trend intemrption; and 4) erosionrelated to mud and hydraulic practices.
Rule 1:Hydration of shales can be caused by one or more of the following reasons:
a) Surface hydration is greatly influenced by the bentonitic content (MBT) of theshale. High MBT shales will have quick hydration and lose stability immediately.An example would be tight hole on first trip tbrough newly made hole inbentonitic and/or gumbo shale. Surface hydration can be minimized by reducinghole exposure (gening-in and getting-out) with good optimization tecbniques.Surface hydration can be prevented or minimized with oil muds and intribitedmuds zuch as Potassium Chloride. Surface hydration can be minimi-ed !yencapzulation (coating) with mud materials zuch as polymers. Generall]' the bestnrle is to get in and get out before hole stability is lost; and in high MBT shaies,this could be within seven days (plus or minus).
b) Osmotic hydration is caused by differences in activity betrreen fluid in porespaces of shale and the mud's filtrate and/or water phase salinity. Osmotichydration generally reErires more time than zurface hydration. Therefore, it canbe minimized by optimizing drilling program to within safe exposure time. SafeexpoSure time is arrived at best by arga knowledge. This area knowledge is
. enhancrd if field people will report (document) the first indications of undrilledshale on shaker. As a general rule, osmotic hydration can best be prevented bythe use of a balanced activity oil-tlpe mud.
c) Hydration can also take place in fracurred shales and alongBlanes (i.e., sand and shale). Capillary action can speed up the hydration processin hair-line fractures. The hydration in fracnued shales and along bedding planescan be minimized by making zure mud has one or more of the following qualities:1) good colloidal content-cake building properties; 2) good plugging propertieswhich comes from aqphalt-type materials; 3) good encapzulation properties; and4) in some cases an oil tlpe mud (some fracnrred shales do not respond well tobil mud(s) - but area knowledge should play an important part in over all materialor system selection. As a seneral rule a mud with good colloidal content, thathas an asphalt additive present, will satisfy most fracnrred shale problems.Minimizing directional problems, when drilling fractured shales, will minimizethe associated mechanical shale problems of ledges and mechanically knocked-offshale.
Rule 2:Shales will lose stability if tripping is not optimized and minimizsd. Surge andswabbing, related to poor tripping practices, poor bit selection and poor drillstring inspection and handling practices, will decrease safe working days in a
16:1
Mrrchison Driltins Schools. Inc.
XVI. SHALES (cont.)
shale. For example, a "ten day shale' can lose its stability in five days if a seriesof string washouts take place because too many trips are reErired. Long runningbits can be justified in many instances because of better hole stability regardlessof economic cost per foot calculations.
In one drilling operation, that required a section of evaporites (anhydrite, salt,marls, limestone) to be drilled the hydrostatic-sensitive marl could not bestabilized until long running diamond bit were used. Jlris minimized zurge andlallssning of plastic shale and enhanced its stability. As a seneral rule optimizedrilling operation to keep pipe tripping 1e 3 minimum and this will minimize sffisstability problems.
Rule 3:Hydrostatic pressure loss or lack of can cause some shales to lose stability.Examples of these shales would be the squeezing marl associated with evaporitesand the sloughing shale associated with pressure transition zones, wherecompaction (dewatering) trends have been interpreted. The squeezing marlsrequires hydrostatically balancing before drilling operations can be rezumed.Surge will balloon these plastic shales, therefore tripping should be minimizedand closely zupenised. Sloughing shale, very prevalent in shale transition zonescan be minimized if mud weight is adjusted to what the fbrmation pore pressureis in the shale.
Formation pressure can be calculated from d'exponents, sbale densities or logs.Sloughing shale usually takes place near bottom (newest hole) and isn't relatedto hydration or over exposure. For example, a driller picks-up to make aconnection and after picking-up a new joint, he cannot engage kelly-drive lushingbecause the bottom of the hole is filled with sloughing shale. This shale isn'tover exposed but simply loses stability because the trapped water is pressured inthe shale and the trapped water keeps the shale matrix from compacting andgaining rock strength. Consequently, the shale "relieves itself" into the hole.The greater part of the overburden pressure (1.0 psi/ft) is zupported by thetrapped fluid instead of being more evenly divided between matrix and fluid.
Once a shale sloughs the driller has to exercise patience.until the sloughing iscomplete. How long a shale sloughs in a particular section is related to the shalesangle of repose (dip and support) and is very unpredictable. Keep lsrming holeuntil the driller can lower the bit without down drag or a hole bridge. The drillerhas to make sure he keeps the problem below him--in other words don't drillahead until hole stabitity is gained. At this stage it requires viscous pills withhigh mud yield values, and sometimes weighted pills to unload the large pieces(and volume) of sloughing shale. The following general rules apply to squeezingand sloughing shale. For squeezing marl, balance hydrostatically before drillingahead. Many parameters can be used as guidelines to evaluate the hydrostatic
16z2
qqqqelJ,cfIJIffIl!;
JJJJ
Mrrmhicnn Dnillino Schonls- f nrADa,,DtItI'a),,
,)
,D,tJ'a,trt!rrrtJ'J'DDDDDDpD|'
DDIDIpppp)
I)
I
XYI. SIIALES (cont.)
balance (i.e., pressure and stroke relationship above and adjacent to the shale,torque, drag, erc.). The mud to drill squeezing marls should either be saltsan[ated with excess encapzulator or an oil mud. In both cases, a hydrostaticbalance has to be maintained. For sloughine shale the mud weight should havebeen adjusted while the pressurized shale (transition zone shale) was being drilled.After it sloughs the main priority switches to unloading the hole and waiting untilthe sloughing stops. Mud weight increase and water loss reductions only help atthis point by aiding hole cleening.
Rule 4:Erosion of shale can cause loss of hole stability. Bridges form near or adjacenteroded hole because of unsupported ledges being mechanically knocked-off andbecause of hole cleaning (a change in annular velocity at the eroded spot causesthe cuttings to "fall outn and create bridge). To avoid this problem design themud and/or hydraulic program to minimize turbulent flow. The yield value canbe adjusted to help suppress nubulence if the pump rate is optimized at correctlevel. Off bottom circulating practices should be closely observed when in shalesections to prevent washed-out hole. The prpe should be reciprocated aLnostconstantly when in shales. As a general rule, the flowrate should be adjustedbetween 30 and 50 gpm/inch of bit diameter. If the turbulent flow calculationindicates hrbulent flow, next to drillpipe, either the yield value should be raisedor the flowrate adjusted to the lower side of the hydraulic range. Polymer mudsenhance or improve hydraulics because they shear thin inside the drill string andthicken-up in the annulus to help suppress turbulence. The flatter flow profileaids hole cleaning.
Note: Many driling people use sloughing and heavi4g shale designation(nnming) ialelshangeably. However, in the discussion aboveheaving shale is a shale that has been over exposed (which meansthat hydration has been given time to take place). It is uzually aproblem off bottom because the hydration process(es) do requiretime. On the other-hand sloughing shale is a problem on bottom(it usually takes place immediately after drilling a kelly down).Sloughing shale has the water present because of an intemrptionin compaction trend-not because of hydration--and it sloughsbecause of weak rock matrix strength and pressure relief.
Formulas:The following formulas are useful in evaluating 1) hole restriction;2) turbulence which causes erosion and mechanical shale problems;and 3) pressure to place below a closed BOP to equte to anequivalent mud weight increase down the hole (to solve asqueezing shale problem).
16:3
XVI. SIIALES (cont.)
l) P- -- = P. l'tlY**)'- resrricrio - dce I SpM""." J
Where:Prcstriction : The pressure difference berween clean hole and a restricted
hole (strokes have to be same to make comparison)
P"to,, : The pressure recorded with the hole clean and unrestricted
SPM"1..! : The strokes per minute recorded with Pr..o (strokes/preszureare recorded together)
SPM*oio"d = The sEokes per minute recorded with the annulus restricted
83.12) Vc= hu.(OD-ID) lvfW
Where: VC : Critical velocity ff/min
OD : Hole size
ID : Drilpipe OD
MW = Mud weight (ppg)
PV = Plastic viscosity
W = yield value (point)
Based on 2100 Reynolds Number
GpM = (vcXoD2-ID2)' ,+.51
r/^ _ 24.51 x Flowrate (gpm),"=ffiWhere: Va = Annular velocity fl/min
GPM. : GPM to reach critical velocity
3) AP*, : (MWh - MWo'") 0.052 X TVD,ho"
AMW.* = M'Woor" +AP-,'
mr*o. x 0.052
16z4(at squeezing or pressured shale)
Mrrrchison Drillino Schrnlc- fn)
)
)p)
)pIDaDItDDl'lrtDDaDDDtDtrt!rrtDDtD)
D)
If)
aD)
)
XVI. SIIALES (cont.)
Where: AP."*
aMwo,.,
I\,f\Mbt
wno,"
TVD16"
TVD.-,"
Max preszure that can be applied at top(under BOP) with shoe limitation
Max equivalent MW at shale depth with theshoe limiting the zurface pressure
I-eak off test mud weight
MW (ppg) in hole
True vertical depth (ft) of shoe
True vertical depth (ft) of shale
at shoe)
Example 1: A shale sEreez,eA at 9,500 feet; the shoe is at7,500 feet and the leak-off-test MW is 17.5 ppg;Wno," : 16.0 ppg. What is the maximum pressurethat can be applied under the BOP with the shoeL.O.T. MW limitations? What is the equivalentmud weight (AMWJ at the squeezing shde depth?
AP.rr : (17.5 - 16) )0.052 x 7500 ft= 585 psi @ased on leak off test
= tU * 585 PsiaMw,_,9,500 x 0.052
17.2 ppg @ 9,500 ft (depth of shale)
Example 2: How much shale restriction do you have in the hole?
Given:
P"."n : 2,000 psi; SPM"."' = 80 SPM;
SPM,ooio.d = 77; Pr..t ir.c : 2100 psi.
P,""o,* = 2000 (+Y\ E0/
: 1853 psi (clean hole reference at lower strokes)
AP,oEir"d = 2100 psi - 1853 psi
= 247 psi restriction due to shale
&ueczin9 @)95CD ft
l6:5
Mnnchison Dri[ine Schools. Inc.
X\[. SIIALES (cont.)
Example 3: Wbat are the new critical velocity if changes are made inflowrate and mud? Given: MW = 9.5; Pv = 10 cps;Yv : 4; GPM = 350 gpm; Va : 182; Vc = t72; GPM.= 332. Changes: 1) GPM : 330 (flowrate change); 2)Yv = 6 (mudchange) W = 12.
1. Flowrate decreases to 330 gpm
A2 1 r
vc= ==ot:f^=lto-@(8.5-5)9.5'
= 172 ff/min
V"= 24.51 x 330(8.52 - 52)
= l7l fl/min (okay - not in hubulence)
Note: If annular velocity is less than critical velocityyou are not in trubulence.
2. The mud velocities (YV and PV were increase)
A2 I r
Vc= ==tt: l==[e.ff in6)$;-5f g.s](8.5-5)9.5'
Va
= 2L0 ft.,/min
_ 24.51 x 350
$.52 - 52)
= 182 fl/min (okay - not in nubulence)
The erosion problem could be approachedhydraulically or with mud rheology changes.
Note:
16:6
Murchison Drillinp Schools. Incf.FFFFFFFFFFFFFpFftpItItItpI'ItI'I'I'rrI'ftI',)
aar,rtaaI.)
rt
X\[I: LOST CIRCTJLATION
[.ost circulation is the number one drilling problem. It is the leading cause of blowouts(uncontrolled well). It is one of the leading causes of snrck pipe and overall hole stabilityproblems. The approach to solving a lost circulation problem is greatly influenced by holeinterval, with references to casing depth and foruration pressure, and by operating practices ina particular area. It should be influenced to a lesser degree by material availability if losses areanticipated in the planning stage.
The approaches to lost circulation are uzually broken up into the followiqg hole intervals:
Top hole - a normally preszured zone (0.465 psi/ft) with only zurface or drive pipe set. Themud weights range from 8.33 ppg (water weight) up to approximately 10 ppg (no barite). Theapproaches to solving the lost problem in this hole section range from blind drilling to seftingsome type of plug. Area knowledge would, hopefully, dictate the best approach.
Abnormal preszure - an abnormally presnrred zone that isn't classified as the completion zone.A deeper intermediate casing or a drilling liner would have been run and a leak off test wouldhave most likely been run below casing shoe and "all" pronounced okay before driiling ahead.The overburden pressure is approximately 1.0 psi/ft and therefore compaction should be greateras you drill deeper. If this line of reasoning is continued the cause of lost circulation in thiszone would almost always be surge related to operating practices. The approaches to solvinglost circulation in this section range from simply waiting (giving time for induced fracnre toclose up) to spotting LCM pills and plugs. Waiting (giving time) and spotting rcM pills, hasgenerally been the best approach to solving induced loss problems.
: 'Losses in completion zones (both normal and abnormal pressures) make up the last category ofhole intervals. In this case the approach is hampered by the choices that are available to solvethe problem without doing pennanent damage to the production zone. Contingenciss eutliningthe materials (or approached) that can be used should be in place. The approaches may varyfrom blind drilling to nondamaging pills and plugs.
The following nrles are applicable to all hole sections.
Rule 1:The number one nrle in lost circulation, common to all hole intervals, is to startfluid in the annulus immediately when losses are detected. The fluid that's addedto the annulus may be water or the mud in the active system. The decisionbetween mud and water should be made ahead of time. In most cases there is a"grace period" of partial losses before total losses. It is prudent to take advantageof this period. Measure the loss rate while circulating across the wellhead (notthe bit) and this rate will be the base number to use when aftempting variousapproaches to solve the loss problem.
If this rule is followed the associatedproblems of kicls, blowouts and stuckpipes are greatly minimized.
17:l
lluchison Drillins Schools. Inc. II
XVII: LOST CIRCIJL.A.TION (cont.)
Rule 2:The base mud, to suspend lost circulation material, should be very viscous. The viscosityand overall zuspension properties will minimize (reduce) drill collar and bit plugging andmake the overall I-CM pill more effective. The minimum apparent viscosity should be25 centipoises (cps). The apparent viscosity is ll2 of the 600 RPM dial reading on thefann viscometer. A funnel viscosity of 51 sec/qt is approximately a 25 cps apparentviscosity. If the base mud nlooks as if it could be walked on without any halo's overyour headn it's probably about right. One of the leading causes of plugged bits andplugged bottom hole assemblies is a base mud tbat is too thin. Cement that has gilsonitein it also requires extra gel-admix to increase the cement base viscosity. This makes thecement plug more effective and minimizes plug$ng of casing float eEripment.
Formula:
(
I(
IIIIItIIIateIIICtIt!aaCteeeI
App.vis. =ry
Funn. Vis. = 26 ser,,lft. + 25
Where:
App. Vis : Apparent viscosity, cps ,.:\.
e600 RPM = The 600 RPM reading on the viscometer
26 sq,lft. = Funnel viscosity of water, sec/ft at 68oF
25 : App. vis., minimum viscosity
Example: The base mud has a o600 RPM reading of 60 and the Fann. vis.is 59 seciqt. Is this zufficient for I-CM base?
e600 = 60
Av =602
-- 30 cps
FV59 > 51
Therefore: The base mud is okay.
Rule 3:An LCM pill is more effective if it accomplishes seali.g, matting and bridging. A goodparticle size distribution is required to meet these three goals. A blend of walnut hulls,
17:2
JelJJJJJaI
Mnrrlrisan Drillino Schrnlc- Inc
FFFFFFFFEfrFfrFFFFrfDtslDfrpfrpftI,frlrItfrrtrt
X\[I: LOST CIRCI]LATION
Rule 3: (cont.)cellophane flakes, and fibers will give good rezults. Some substitutions can bemade; however, these three products have been proven in the field and also on theAPI I-CM tester. Mica breals down into sub micron solids and can be detrimental topermeability, rtrd therefore should not be used around production zones. Mix I-CMinto a viscous base just prior to pumping it. The pill should be fresh (new) for the bestresults. When an IfM pill is circulating out (to the surface) it should be routed acrossthe shale shaker (or in a special holding tank). Do not by-pass shaker because solids andpaleo control will be lost. When solids control is lost the mud weight will increase andthis will in tun aggxavate the loss and stuck pipe problem.
Rule 4:Locate the loss zone. The most effective use of LCM pills and plugs is when depth ofloss zone is known. A wire line temperahrre suvey or a "poor boy" wireline-ragtechnique can be used. A large increase in temperature will take place at the loss zonebecause the mud below the loss zone has been setting in the hole and has reached ahigher static temperature. When a rag is tied on to a slick line and run in the hole therag will be zucked into the loss zone and the wireline will get slack in it. A depthcounter needs to be engaged during the operation. For best results in sealing a knownloss zone, a mixing sub on the end of the drill string is positioned about 100 feet aboveloss zone when spouing a pill or a plug.
Mixirp Sub'*Mixing sub is a oilled joint of drill pipethat has been sloned and 'orange peeled"on its bottom. It is used for all LCM pillsand plugs (cement, gunk, etc.).1@ft
t
\ *r.o,.
Rule 5:Use a minimum circulating rate when drilling with losses. A minimum sirgulxting ratewill lower the equivalent circulating density (ECD) throughout the well bore andconsequently will lower the loss rate. The ECD can also be lowered by reducing themud yield value. A combination of reducing flowrate and lowering yield value is moreeffective. The minimum circulating rate is equal to the square root of the hole diametertimes the product of ten times the hole diameter.
Formula:
Min circ rate = l0 d/a
Where:
d : Hole diameter in inches
min circ rate -- Minimum circulating rate in gallons per minute
L7z3
XVII: LOST CIRCULATION (cont.)
Rule 5: (cont.)
Exanple: The well is losing 15 barrels per hour. What is the minimumciranlating rate the driller can go to and still continue to drillahead? Given: hole size 8-ll2 inches.
Min. circ. rate = 10 x 8:5 tffi
= 248 Wm
ffis minimum circulating rate that drilling could be continued with(to prevent bit balling, etc.)
Rule 6:Estimate balancine mud weight if possible. There are many cases where ahydrostatic equilibrium can be established by adding water to the annulus. Thevolume of water should be measured into the annulus. When the hole stopstaking fluid (no loss or no gain) a hydrostatic equilibrium has been reached. Atthis point the length of water column is calculated. Equivalent mud weightcalculations can now be made at a few points in the hole, starting at the shoedepth. After making these calculations a decision can be made on whether tolower mud weight and how this task is to be accomplished. If the decision tolower mud weight is made, the zupenrisor should make a decision concerning thezurface pits, where to place the bit and how many mud weight points to cut themud weight each circulation.
If the loss problem was caused by loss of solids control the decision is often madeto dump the surface system and clean the tank (this would be only in unweightedmud sinntions). In weighted-mud zones, the decision to cut mud weight istougher to make, and when done a close surveillance has to be maintained. nTru-
waten mud balances need to be used when working with heavy muds and partic-ularly when mud weigbt adjusting is done. Air as entrained gas can be the causeof the loss problem in weighted muds and if this is the case the hydrostaticbalance needs to be made with the assistance of the pressurized mud balance(Tru-wate).
Formulas:
lvfW" =(L*XG-)+@epth-L- )G-
uo, = u{
Depth x 0.052
(Mwr - lvfw2)l(lfrt, - il{w.)l
17z4
Where: MWE : Mud weight equivalent (ppg) at depth of interest
XVII. LOST CIRCLTLATION (cont.)
Where: (cont.
G*
Depth
G.
vo,
vF
Mwl
Mw2
Mwd
Example:
L*, =
what is the maximum dilution necessary to reduce the mud weightto the lowest calculated mud weight equivalent? Given: depth =7,000 ft; 9-518' shoe - 3,000 ft; Dp - 5,, 19.5; MW - 9.5 ppg;volume water added to reach hydrostatic eguilibrium - 25 barreli;final volume desired = 1500 bbl.
= kngth of water added to annulus
= Gradient (psilft) of water (fresh water = 0.433 psi/ft;sea HrO = 0.455 psilft)
= Depth of interest (ft)
= Gradient (psilft) of mud (MW x .052)
= Volume of mud to dump and volume of dilution fluidto add to reduce mud weight (banels)
- Final volume (toal active system) desired after dilution
: Initial mud weight (ppg) before dilution
: Desired mud weight (ppg) after dilution
-- Dilution fluid weight (ppg)
= 500 feet
L
2s bbl0.0s bbvft
MWo =e.m gooo , oo52
= 9.3 ppg
lvfwo =.-7@0ft 2000 x 0.052
= 9.4 ppg
lTzS
Murchison Ilrillinp Schools. Inc.
XVII. LOST CIRCT LATION (cont.)
Example: (cont.)
vDr = 1599 -(9'r-9!).(e.s - 8.33)
= 257 bbl of mud should be dumped and then 257 bbl ofwater added over one or more circulations toredrrce mud weight from 9.5 to 9.3 ppg.
Note: The hydrostatic eErilibrium that was reached, after adding25 bbl of water in the annulus, is a static equilibrium (noECD included). Uzually the mud weight bas to be lowered apoint or two lower than the equivalent mud weights calculatedfrom static pressures.
Rule 7:If total losses occur estimate the fluid level. When a naorral fracnue is
penetrated total losses often occru. When the fluid level drops in the hole the drillstring will lose buoyancy and a gain in string weight is noted on the weight-indicater.This change in weigbt-indicator weight can be used to calculate the fluid level. Thefluid level can be used to calculate the static hydrostatic eErilibrfum at the fracnredepth and the balancing gradient (psi/ft). If this balancing gradient (Gg) is below afresh water gradient (0.433 psilft) a blind drilling or air drilling technique should beconsidered. I,CM pills and plugs are generally ineffective when the balancing gradientis less than a fresh water gradient (0.433 psi/ft).
Formulas:
DFL = AW(DP"*Xl-BD
(DF-DJ lv fWHx0.052)
'Where:
DF
= Depth of fluid level (ft)
: The increase in string weight on the weightindicator caused by loss of buoyancy.
: The adjusted weight of DP that includes tooljoinrs (lb/ft). (Can be found in RPTG orMurchison Drilling School's Sflell ControlManud).
= Buoyancy factor
_ fes.u - lvfw (pee)l-L ** ,
GB=
DFL
AW
DP"r,
I(
!IIIIqqIIIqqIIIIIqIIIII(
IIIIII(
I
17:6
BF
Murchison Drillins Schoob. Inc.
XV[. LOST CIRCULATION (cont.)Where: (cont.)
G"
DF
MwH
: Balancing gradient (psi/ft) at fracture depth= Depth of fracnre (ft)
= Mud weight in hole (lb/gal)
Example: A fracrure was encountered at 6000 feet and total losses occurred. Thestring weight increased 5000 lbs (AW). What is the depth of the fluidlevel @fl and what is'the balancing gradient (GB)? Given: DP : 5,19.5, XIf, nEn with adjusted weight of 20.9lb/ft; mud weight 9.1 ppg;BF : 0.86.
Drr. = 5,000 lb(20.e rb/ft)(l-0.8o
= 1709 feet
ta _ (6000-1709)9.1 x0.052-B - 6-000 ft
= 0.338 psy'ft (This is tsss rhan a fresh watergradiegt which uzually means thatconventional lost circulation pills& plugs are ineffective.)
Rule 8:When circulating out a kick observe drillpipe pressure closel]' each time a change is madeon annulus choke. If the drill pipe pressure does not react to an annulus chokeadjusment it indicates some zone is taking fluid (partial losses).'Inst circulation is thentrmber one associated problem to well control. Once a zone breaks down (lostcirculation), pressures (dp and ann.) do not represent an accurate hydrostatic balance andconsequently either losses or gains can be further induced. It is generally better to stopcirculating and wait a short time to give the zone time to heal. Observe the well closelyduring this shut down period. Pressure changes (increase) usually indicate percolationand if percolation is taking place circulation should be resumed at a lower rate @oldcasing pressure constant while aniving at new circulating rate and pressure and thenmaintain driltpipe pressure and stroke relationship constant). Small irmounts of fine lostcirculation material (walnut hulls) may help seal partial losses. Be very careful not toplug bit.
Kict 8ein9 CircuLted Out
L7:7
Murchison Drillins Schmls. Itr2!tTDDDDrDrDrDIDrIDIIIlrrlll
IllItTItftlpp
F
X\IItr: DIAMOND BITS
Natural diamond bis have tremendous pump-off forces created because of preszure drop beneaththe bia. This pump-off force has to be overcome with applied weight to keep the bit on therock. The pump-off force, with some styles of diamond bits, can exceed 50% of the totalapplied load while drilling. This causes the tnre bottom hole load betrveen the diamonds andthe rock to be less than balf of the indicated weight-on-bit. Pump off forces are three or fourtimes greater with the radial flow bit versus the cross-flow bit but when this force is accountedfor the performance is similar.6
Rule 1:Account for pumpoff force on a diamond bit to arrive at tnre weight on bit. Theprocedure described and illustrated below should be done tbree or four times during thelife of the bit. The pumpoff area (and force) gets higher as the diamond standoffreduces (as diamonds wear). The procedure below should start after "building the nest."'Building the nestn is dri[ing terminology related to breaking the hole in or contouringthe bottom of the hole to fit the bit profile. When drilling people talk about breaking inthe bit slowly they really are talking about 'building the nest. " Bits come from thefactory ready to drill and require no breaking in-but the hole does require shaping to "frtthe bits personality. "
Formula (procedure) and Example:
To Obtain Pump Off Area and hrmp Off Force
Procedures:
1) Take off-bottom pressure reading.2) Wittr bit about 4 inches off bottom, slack off slowly.3) Meazure change in pressure (AP) and corresponding weight.4) Plot on plain graph paper.5) At point of deflection (slope shange) record AP and weight on bit.6) Calculate pump off area:
AE = Tlt on bit = tt':f tF = 25.L sq inAP 605 psi
7) Calculate tnre weight on bit for any given weight indicator weight;i.e., AP = 635 psi w/38,000 lbs : 635 psi x25.1sq in = 15,950 lbs.
Therefore: 38,000 - 15,950 : 22,0501bs tnre weight on bit.
8) As bit dulls, repeat this procedure to get new pump off area (and pumpoff force).
Ref. 6: Variations in Hvdraulic Lift with Diamond Bits. Winters and Warren. SPE 10960.
18:1
X\[tr: DIAMOND BITS (cont-)
wE16l{IINUCATOR
n,ilP-0FFFORCE
BITPRESS|nt
DROP
?RUfwEr&r?-sFltr
F as-
l@rr
tt
rl-
Wtaro.r..g,ltr
oFi 60IT0i4 PU 4Pt0 otF 0RrruN6
G@
o
o
o
PI'I{PtffssuRt fc- l
\ z5z5 7\t5I./
&\1[e/,5.2*. '8-
- PrnP-rrAREA
2rzs-1920 s
605 P:il
o
535 ?51r ?5.1 tN2t5,t50 Lt
?555- 1920Tiresr
38.@0- 15.9s0:-
122.050 r I I
rlt(tt!!|lJJJJJJ
18t2
= Hi= ?5'ttt't'
Murchison HUirySchmb.InplcFIel -
l"ItrlDtrtEErDEFlr
I
5
I
>DDD
:aI:
!DEI!I
XIItr: DIAMOI{D BITS (cont.)
Rule 2:Run a drill-offtest shortly after measuring pump-offarea (and force). The drill-off test is usually run to find the most effective weight on the bit for a givenrotary speed, a given hydraulic horsepower and a particular formation (rockhardness). Influencing limitations can be the available bit weight from the drillcollar assembly and torEre limitation for the drill string.
1) Adjust the tnre weight on the bit to some nardmum weigbt (basedon available drill collars generally).
2) Lock the brake.
3) Measure the seconds it takes to drill off each increment of bitweight (i.e., seconds per 2000 lbs of weight cbange on the weighrindicator).
4) Record these increments in a table (and/or plot on semi-log paper).
5) The best weight on the bit is where the fewest seconds are requiredto drill-off an increment of bit weight.
Note: A bad kelly and/or kelly-bushing can make constantbit weight impossible and very misleading. Forexample, when weight is slacked off the kellybushing takes the weight at first and it graduallygoes to bit. A flick on the weight-indicator willshow this erratic feed-off of weight.
18:3
X\IItr: DIAMOND BITS (cont.)
Formula (Procedure) and Example:
1
71JIaIJJJJJ
D r1D - Grnsth of dPxDil-otr weighOrLv'r'
(DP adi vtt'lQ2l7XDrill-off time in sec)
JlfJJJ_ (8781-720X2000)
(18X2217X30)
= 13.5 ftIu
aj
JJJ,a
Tcrt l{o. I
D.prh frrl R,Ptl ltf,t. 3CC. i l tv.
to Lel In&.3E 50 50
35 t l 0 toa{ r70 l0
3Z 235 55to zt5 aol 5 375 t0
26 16s aoz l 505 t0
,7 360 q3
zo 635 75
l 8 7r0 t05t 6 t90 t50
lcll UK No. I
!-5 -! E
9 ! r .
i ! ' .A l m9E*
E::U|R -a
G
F
Gr
E
t0IGF
F D ' C T
t . i9ht-on-bi t (x r000) lbs.
-/- x ttrt tlo.2 |I
Xot ogtim.rtnrright .t ttcT.rt YatlO.
o T..t l.o. I liaoio charteratottrrrl ion.trl lXvALlD.
i-----,OO lbr.
'l
t a n
T'
Notc: lt i: crrcntirlthrt fh. rpn bc coo-3tant throughout thcdrill-off tcat. Adis3tthc throttlc if nccci-r.ry tnd utc rFloountcr.
18:4
Murchison llrillinp Sctmls- Im -
X\IIII: DIAIVIOITID BITS (cont.)
Rule 3:Stabilize a diamond bit. A diamond bit is required to be ttfirrnn in its nest
(intimate with the bottom of the hole) for the hydraulic system to be completed acrossthe face of the bit and diamonds. The feeder-collector systen works better without anywobble or thntst loading. A side benefit of good stabilization, other thnn making thehydraulic system work, is that a more effective hole diameter (better drift diameter) isdrilled. If a medium to hard formation is being drilled a stiff hoolup will not followa limber hooknp without the possibility of getting stuck. Therefore, it is important todrill the upper hole with a similar botom-hole assembly (stiff hookup) prior to goingin the hole with a diamond bit.
Formula and Illustrations:
LIMBERHOOKT'P
Path travclcd bybouom of bit
Path taveled bytop of bitX = Bit diancerX' = Effcctivc hole
dianetcrReduccd EffcctivcHole Diarncar
Drift DIA = Bit OD + Collar OD2
Rule 4:When using PDC (polycrystalline diamond compact) bits make sure thehydraulics are good before going to bottom because the nozzles are easilyplugged. Many times aftg1 making a connection or a trip the rate of penetrationwill be reduced because part of the nozzles were plugged when the bit was puton bottom with inadeEnte hydraulics. PDC bits have a tendency to ball upwhen using water base muds and, therefore, need a higher minimum flowratethan other bits. For most bits 30 gpm/inch of bit dianreter is the minimumcirculating rate.
Fonnula and lllustrations:
Qnin : 12.72 (D)t'47
18:5
!
X\rltr: DIAMOND BITS (cont.)
Where: Qmin
Exarnple:
: Minimum circulating rate for a PDC bit (gpm)
= Bit diameter (inch)
What is the minimum circulating rate for an 8-ll2 inch PDC bitand how does this compare with the sane size insert bit?
QminPDc = 1232 (8'tr'47
296 gpm
Qminb..t = 30 gpm/inch x 8.5 inch
255 gpm
The QMin for PDC bit is 41 gpm higher than the equivalentsize insert bit. Hydraulics on high side are equivalent.
D
Ecldr Com. &Co,rar ilolrlca
n|,ro.d
18:6
Mrrr.ehicnn fHllino Sohnalc - fnrIatf.FFFF.FF7?7F77ftFFFt,t)I,t,)
rta,Itrtf);
I'fD,)
JD,t,t)tJ',,
IrD
XX: DIRECTIONAL DRILLING*
"Straight holes" are not necessarily vertical holes and vertical holes are not necessarily straightholes. Most wells, as viewed from the surface, would have a helical appearance. Computerplots of some "straight hole" multishot surveys look like a bowl of spaghetti; the direction mayghange direction 180 degrees within a short distance. Directional wells are even worse thanvertical wells if proper directional driiling practices are not observed.
The rules, or zuggestions listed here, apply to dritling practices whether the objective is to drilla vertical or deviated hole.
The considerations when planning a directional well are:
o Depth of hole and displacemento Hole sizes and collar sizeso Casing poin*o Maximum build and/or drop rateso Maximum average angleo Formation types, dips, and expected ROPo Mud weight, temperature and mud gpe. Well histories and tendencies in the area
Operating practices on directional wells need to be directed at: mud; hydraulics; connections;trips; hole cleaning; and the special trends to monitor to minimize stuck pipe. Mud'viscositieshave to be higher. For instance one of the earlier rules-of-thumb for funnel viscosity was fourtimes the mud weight Gpg). For a directional well this rule-of-thumb would be five times mudweight (ppg). Hydraulics horsepower should be higher to account for mud motor losses andflowrate designed with qpecial emphasis given to hole cleaning. Connection practices need tobe optrmized with special attention given to preventing stuck pipe, surge'and bit darnage. Trips(short and long) need to be optimized and zupervised closely. Special reciprocating and rotatingpractices should be implementrl when nyns fo remove cuttings that settle out on the low sideof the hole. The key drilling parameters have to be recorded on a trend basis. A driller shouldbe told to monitor: the preszure-stroke relationship; the drag trend (up dragdown drag anddifference between up and down, sometimes referred to as a AW) and the torque trends. Manyhole cleaning and stnck pipe problems can be caught in the early sages if good discipline isexercised at the drillers' console. [See drill string design for "rules" applicable to bottornholeassembly design (Section X)ilD.l
Rule 1:When a direction or drift angle is required to be changed (drop or build) the needed anglefrom a string (or compass) should be doubled. For instance if the 6els angle had to bebuilt from 20o to 25' (5" change) in 500 feet you would need to plan on 2ll00 ft (10"change) because the average angle is 1/2 this (previous drift + present drift + 2). Thisassumes you will have constant urnr or angle change to the target.
Ref. *: Special thaDls are given to Bill McDowell, ferry Haston, Jim Chappel, Preston Moore,Ellis Austin & Murchison Drilling Schools.
19:1
Murchison lhillins Schools. Inc.
XX: DIRECTIONAL DRILLING (cont.)
Rule 1: (cont.)
1. Ki*ofiFirn2. Suilds.crim3. Droo Scctiqr4. Sitc Tr.cf5. Fch
Rule 2:To get the measured depth (MD) for the casrng point (given in TVD)the formula below.
Formula: di4qqoli.lIqqqqofJJJJJJ
Where:
MD_- _ (Casing Point TVD - Present T\ID) + MD-_-'-css CoS Average Angle
-'-prcscnt
MDos. = Is the measured depth at casing point (which is usuallyplotted on program in TVD)
Casing Point TVD = TVD that casing is prograrrmed to be nrn at
Present TVD : Calculated TVD at present survey station
Average Angle : The average angle between present surrey station andcasing point planned angle
A tool pusher needs to know the measured depth at casing pointso tbat he can get his casing taltied and spaced out. Given:present TVD = 3000 ft; casing point TVD = 3500 ft; averageangle betrveen present station and casing point is anticipated to be25o; and meazured depth at crurent survey station (present depth): 4000 ft.
6. $rleor Cerirr7- tadfiGd S.TlDc W€fl8. &&mdHotd9. trrmcdinrccrirr
f O. 8e,rr Ho|e Ass.rr$tv
t9z2
Example:
aJ,)
)
I)
)
-
r-
)
)
II'r,IItItaItttttaattt!l,
IatttIIaIat
IilX: DIRECTIONAL DRILLING (cont.)
Rule 2: (cont.)
Example: (cont.)
w* =ffi +4oooft
= 4552 ft (measrned depth for casing shoe)
Rule 3:The averags engle definitions and formulas are'given below with an example of foursurvey stations calculated.?
Definitions:
1. Surface Location: The position, tatinrde and longinrde, on the zurface of theEarth of the Well Bore. For directional drilling pu{poses, this will normally beconsidered as the n7&ro" point for all calculations and measurements to the TargetLocation.
Target Location: While it may be given as a position on the face of the Earth inIatinrde and Innginrde, for practical purposes in directionat drilling it will beregarded as a predetermined position at a specified distance and direction fromthe Surface Location.
Measured Depth (MD): Pipe Talley measurements from Rotary Table to the Bit;total distance drilled at any given momenJ.
Course Lrngth (CL): The measured distance drilled between any two surveypoints.
Drift Angle flnclination): The engle of the wellbore at any given survey point inrelation to vertical.
Averaee Angle: The average between drit englgs taken from any two consecutivesurvey points.
True Vertical Depth (TVD): The dist?nce straight down - vertical - from theSurface l,ocation of the Wellbore to any horizontal plane which intersects theBottom Hole Location.
2.
3 .
4.
5.
6.
7.
Ref. 7: Murchison Drilling School, Workshop Manual, Murchison Drilling Schools, Inc.
19:3
Murchison Drilling Schools. Inc.
XX: DIRECTIONAL DRILLING (cont.)
Definitions: (cont.)
8 . Vertical Section (VS): The distance horizontally berween the SurfaceI-ocation and the Target Location along a stright line in a specifieddirection. This may be viewed on the Vertical Plan as the distancebetween a point directly vertical under the Surface l,ocation at total TVDto the Target Location at total TVD, or on the Horizontal Plan as thedistance between the Surface lncation and the Target I-ocation on theSurface. These trvo lines as shown on the Vertical Plan and theHorizontal Plan are the SAIvIE identical line. This is also calledDEVIATION. (However, it is NOT to be confirsed with CLOSURE).Example description of Deviation or Vertical Section: 2250'at N8OW.
Deviation: Same as Vertical Section, except as seen fromthe HorizontalPlan.
Clozure: The horizontal distance and direction between the Surfacel,ocation and any given survey point on the Horizontal Plan. If a wellwere drilled perfectly, the Closure would be the same as Deviation andVertical Section. However, since the odds againsl this are astronomical,for practical purposes, they must never be considered to be the same.Closure may be cdculated at any interval in the atniog program or atTD (Total Depth). Example description: 2275' in a direction ofN7720',15',W.
Course Deviation: For clarity, regard Course Deviation to be the sameas CLOSURE, DISTANCE, but only for that distance'berween twoconsecutive survey stations. Some confusion rezults from the use of thistenn. "Course Deviation" as well as the term "Deviation." Bear inmind that "Deviationn refers to the Planned, or Proposed Deviation(which is a predetermined distance and direction) from the SurfaceLocation to the Target Iocation. CLOSITRE refers to that Deviationacnrally drilled (which is the well bore distance and direction from.theSurface location as acnrally dritled). Course Deviation is that segmentof Clozure DISTANCE (but not direction) which exists between twospecified survey stations.
Average Direction: The average berween two direction angle readingstaken from any two consecutive well bore survey points.
Directional Difference: The difference (absolute, that is, always apositive rumber) between the Average direction and the Proposeddirection at any given survey point.
11 .
9.
10.
L2.
13.
19:4
Murchison Ihilline Schools. Inc)
aDDt)aDaDaDDa)
tItDttDDDDDl)
)
DtIIII)
t)
t,
)
)
)
)
)
)
I(X: DIRBCTIONAL DRILLING (cont.)
Definitions: (cont.)
14. Section Difference: The rezults of the final calculation for the VerticalSection for any given Course l-ength. This calculation (given under"Calculation Formulas") shows the true distance the well bore has movedfrom vertical toward the center of the Target location and is NOT to beconfirsed with CLOSLIRE. It is to be added to any previous Verticd Section totalto show the correct cumulative Vertical Section.
Rectangular Coordinates (North/South): Distance North (+) or South (-) utilizingAZMUTII calculations from Surface Location (considered to be "zeron).Imagine the Surface Location to be on the Equator and you are facing NORTH.If you walk forward (North) for 10 feet, consider it to be PLUS 10 feet. If youwalk backrvard (South) of the Equator line, consider it to be MINUS 10 feet.Always think of the Surface Location as sitting at "zoro" on the Equator. Anydistance North of this imaginary "Equator line" is a PLUS (+) number and anydistance South of the line is a MINUS (-) number. Utilizing QUADRANTcalculations, however, will NOT result in plus or minus numbers. You willalways know the correct henisphere because the reading will be, for example,NORTH 40 West, NORTH 40 East, or SOUTH 40 West, SOUTH 40 East.
Rectangular Coordinates (EASTAilIEST): Distance East (+) or West C) utilizingAZMUTH calculations from Surface Location (considered to be "zero").Imagine the Surface to be sitting on the Zero Meridian (North-South) line as wellas the Equator (East-West) line. Now you are facing EAST. If you walk forward10 feet, it is PLUS 10 feet. If you walk baclorard 10 feet (West) of the zero lineit is MINUS 10 feet. Any disunce East of the zero line is a PLUS (+) and anydistance West of the zero line is a MINUS C). Utilizing QUADRANTcalculations, however, will NOT result in plus or minus numbers. You willalways know the correct hemisphere because the reading will be, for exampleNorth 40 East, North 40 WEST, or South 40 EAST, South 40 WEST.
Proposed Direction: The ntheoretical" or planned direction from the SurfaceLocation to the Target lpcation.
Azimuth Directions: All the points or compass readings from any given fixedlocation starting with 0 cloclovise to 360o NORTH : 0o; or 360o EAST = 90o;SOUTII = 180o; WEST = 270o.
Bearing Direction: Division of the Azimuth 360 points of the compass into fourequal QUADRANTS of 9CP each. NORTH is always 0o and SOUTTI is always0'. EAST is always 90o and WEST is always 90o. HENCE: Due NORTH canbe either N tr E or N 0o W; due SOUTH can be either S 0o E or S 0o W; dueEAST can be either N 90" E or S 90o E; due WEST can be either N 90o W or S9tr W. 45o Azimuth = N 45o E; 135" Azimuth : S 45o E;225 Azimuth = S45o W; 315" Azimuth : N 45o W.
15.
16.
L7.
18 .
19.
19:5
Murchison lhillinp Scimls. Inc.
)ffi: DIRECTIONAL DRILLING (cont.)
Definitions: (cont.)
19. (cont.)Azimuth to Bearing
NESESWNW
20. Conversion from Bearing to AZMUTTI:
(a) NE QUADRANT:o) sE QUADRAI.IT:
(c) SW QUADRAI.IT:
(d) Nw QUADRANT:
Example and Forrtula:
Calcrrlation Formulas :
Given:
(1) Tie-in information:
No changeSubuact from 18CPPlus 180Subtract from 360
No change N40E : 40o AZ18ff MINUS Quadrant reading S4ffE :180o - 4A : l# AZ180 PLUS Quadrant reading S40W :180o + 40o : 220. A2360" MINUS Quadrant reading N40oW :360 - 40 : 32V AZ
Meazured DepthDrift AngleTrue Vertical DepthVertical SectionDirectionSouthWest
: 4023'= 18.75o:3968.7t '= 327.O1': S77V (257" AZ)= -'13.97': -320.40'
(2) Objective:
(3) Survey Station(point) #1
235o',@ S83"W Q63 AZ)
Meazured Depth : 4lt5'Drift Angle = 19oDirection : S79o
Murchison Ihilline Schools. Inc
3.
FFFFFFFpFFFFFFFftFpFFpFftFtrFFItFpFttFFFFpFItb
I(X: DIRECTIONAL DRILLING (cont.)
Example: S7915'20'W = 79.26oW. [With the Hewlett Packard 41 calculator,Key-in: 79.1520, XEQ HR, :79.2556 (S79.26TDI
1. Calculate Average Direction:
Average Direction = Previous Direction + Prese,nt Direction
Example: S77'W + S79"W
2
= S78"W; or
Note: This example for BEARING calculations is applicableONLY if both directions are in the SAIvIE quadrant. Ifthey are in DIFFERENT quadrants, other rules applywhich are too complex for this short example. It issimpler to convert to Azimuth for calculations.
Calculate Directional Difference :
Directional Difference : Proposed Direction = Average Direction
Note: Directional Difference shoutd always be a positive (+) number.If the result is negative (-), change the srgn to positive (+).
Example: S83oW - S78oW = 5oi or 263o - 258o = 5o
Calcula0e Course Leneth
Course kngth = MD at present station - MD at previous station
Example: 4ll5' - 4023' = 92'
Calculate Average Drift Ang{e:
Example:
, ^ ... ^ -r- _ Previous Drift Angle + Present Drift AngleAverage lxrn Angr"
Calculate True Vertical Depth for this Station:
True Vertical Depth = COS Average Drift Angle x Course Length
Example: COS 18.875o x92' : 87.05'
257" + 259" = 258" AZ
2.
4.
5.
L9:7
XX: DIRECTIONAL DRILLING (cont.)
Add TVD this Sation to Cumulative True Vertical Depth:
Example: 87.05' + 3968.71' :4055.76'
Calculate Course Deviation:
Course Deviation : Sin Average Drift Angle x Course kngth
Example: Sin 18.875o x92' :29.76'
Calculate Section Difference:
Section Difference : COS Directional Difference x Course Deviation
Example: COS 5" x29.76' :29.65'
Add Section Difference this Statiou to Cumulative Vertical Section:
Example: 29.65' + 327.01' :356.66'
Calculate Rectangular Coordinates (North/Souttr) for this Station:
(Nortb/South) Coordinates : COS Average Direction x Course Deviation
Example: COS S78"W x29.76' = South 6.L9' or COS 258o x29.76' : -6.19
Add Rectangular Coordinates (North/South) this Station to theCumulative (North/South) Coordinates :
Exanple: -6.91' + -73.97' : 80.16'
Cdculate Rectangular Coordinates (East/West) for this Station:
(East/West) Coordinates : Sin Average Direction x Course Deviation
Exanple: Sin S78oW x29.76' : West 29.11' orSin 258' x29.76' = -29.1L'
Add Rectanzular Coordinates (East/West) this Station to theCumulative (East/West) Coordinates :
Example: 29.1t' + -320.40 = -349.51'
6.
7.
8 .
9.
10.
11.
t2.
19:8
13.
Mrnchison Drillins Schools. IncI'EFFfDppFlDpIrDIrIrFl
XX: DIRECTIONAL DRILLING (cont.)
14. Calculate CI-OSURE:
Closure DISTAI{CE = y'Total Latitude2 + Total Departure2
Example: 80.162'+ 349.512 = 358.58/
closure DIREcTIoN = ArcTan (Tan-l) f Ed,?*ry")\ Total Latinrde /
Example: Tan-l ffi)
: 77.08oor S77.08"\il, or s77t4'57w or
257.08o, or 257W'57'
Closure may be stated as:CLOSLJRE: 358.58' in a direction of S77t4'57"W or
358.58' in a direction of 257W'57'
Note: There are other fonnulas for arriving at Closure distance anddirection. However, to avoid confrrsion in this limited example,we will utilize only the above.
15. Calculate Dogleg Severity:
Dogleg Severity = COS'I [(COS Prev. Drift Angle x COS Pres.Drift Angle) + (Sin Prev. Drift Angle xSin Pres. Drift Angle x COS Degrees of
Direction ghanqe)l * 10Course Length
Example:
COS-! I(COS 18.75 x COS 19) + (Sin 13.75 x Sin 19 x COS 2\ * #
Note:
COS-I K.946930 x .945519) + (.321439 x .325568 x.999391)l x 1.086957
COS-! (.89534 + .104587) x 1.086957 =COS-' (.999927) x 1.086957
.693131 x 1.086957 : .7534 or .75
To avoid error, Sin and COS rezula should be carried out to6 decimal places. Hand held calculators perforrr this functionautomatically.
19z9
IHl;IH
IFIHtolFll)-(totzt>
t5IF
IFl2loooE
F\0
o
o0rtatrf -?,ltD f|o.
ltArt -t$l llo. or3riElr.D.a.
ar.orx:tl Itloi 0 stla l26tcAzl frafl- ot- ccrn^r|ol
E.li
3..dO.rr
Grdlsarr
O.{rr'lr &n
!$.
Yanad0.ri
JatllolLtri
Ua{i{l-d..
Lf. CrilOll. OFdh
oiliOr.66
s Dt.oto.D
Goamn o.mrtl€L atCrr[.rur Ooaoxttlfil h h H h b lr x
rott L t ttal tt !t l DI 3 7i It t1 - lll l0
.7 t t t t l tl I t am ti t5 l0t! tl t5l la l ! l ! s t ! w rt I t -2! t - t0 6 - t t ! i t
l l l I i l ( r l rl (3t ( 't ! I l ( t ) 2l l l 0 ill l t ( r t l
nr l URE a 3tl. tl h l n . o s Il i7"
ttlI I I I I I I III I I IIlllttllttllttrrrrr..""-^
Murchison l)rillinp Sclools. In<?2DItl.l.tIpptr,tIIIrlIltrrIrDttttr'rtrlItIIIrDIaaaaaaI
)fi. STUCK PIPE
The causes of stuck ptpe are broadly classified as mechanical or differential. Mechanicalsticking is caused by deterioration of hole stability (shale problems, hole cleaning, etc.) and./ordirectional (crooked-hole problems. Differential stickine is caused by mud pressrue overbalanceand is influenced by drilling practices, type mud solids, perureability, bottom-hole assemblyclearance, permeability, bottom-hole assembly clearance, coefficient of friction and thelubricating characteristics of mud. Good monitoring and operating practices will minimize bothfypes of plpe sticking. An ounce of prevention is worth a pound of cure. Drillers are told twothings when they are broken out (as drillen): don't let the problem get on top of you and if youdo get stuck take quick action to free up the pipe (or frsh). Part of this recommendation dealswith preventing stuck plpe and part of the recommendation deals with freeing-up the pipe orgetting the fish out successfully. Time is of essence because hole stability deteriorates withtime. What starts out as differential sticking either becomes mechanically snrck or amechanically sruck problem worsens. The following priority rules-of-thumb are useful insolving snrck pipe problems.
aI
FORCE REOUIRED TO PULL FREE
{NORMAL FORCVUNIT I..ENGTHIXI-ENGTH lN COIITACr WITH
PERMEABLE FORMANONIxcoEFFroENT OF FR|CTIONI
Differential Stickins
Fdilr =K(AP)Area
: Sticking coefficient(0.2 water base mud)
= Differential pressure= Contact area
=(L) &-lC-5f t 3
: lR dc suck
Circumference = r x Diameter
@:K
(AP)Area
Area
Example6-114'dc
1/3 stuck
APL
FdilT
= 3-1416 x 6.25= 19.635 (rounded otr 20)
20'= = O . )-=-
t- 1200 psi= 200 ft permeable zone
_ /n.\ (12001bX200 ftX12 inx6.5 in)- \v.z)s q n
= 3,744,000 lbs
CONCLUSION:FORCE TO PT]LL FREE INCREASES AS(A) LENGTH OF PIPE IN CONTACTIITTH
PERMEABLEFORMATION INCREASES.(B) COEFFICIENT OF FRICTION BETWEEN
PIPE AND WALL INCREASES.
20:L
)fr. STUCK PIPE (cont.)
Rule l: Measure stretch and estimate surck point (ESP). This will help evaluatewhether the prpe is surck in the blowout preventers, keyseated up the hole orshrck near the bottom hole assembly. (See the formulas at end of this section.)If the ESP is near bottom and if the driller can circulate, a further aszumptionthat the ptpe is differentially sfirck can be made. Differential snrck prpe canbe freed up by spotting oil; lowering bofiom hole hydrostatic by one of thereversing techniEres; drill stem test tools or; by other similar methods.
If fishing* is necessary make back-off in unquestionable-free plpe Good torqueresponse). Backoff in full joints (not crossovers, stabilizen, etc.). Alwaysconsider well control and panicularly if kelly is in the surface blowoutpreventer. Sometimes a mechanical backoff, followed by spacing out, isnecessary prior to running a wireline tool so that a lubricator can be used.
*A fish is any undesirable item(s) (i.e., tool, eguipment, or object) in a casedor uncased wellbore that stops or retards operational progress. It can be therezult of snrck pipe - back-off operations; drill pipe, dritl collar or otherdorvnhole tool failures (i.e., twist-offs); bit cones or bearings left in the hole;stuck logging tools; or any other undesirable item left in the wellbore.
Make an enalysis on how many days (or hours) fishing can be economicallyjustified before fishing cornmences. Remember a successful fishing job is onethat is economically and operationally zuccessful. Many socalled operationalsucresses are economic disasters.
Draw a picture or diagram of fish and fishing string. Be accurate with OD''s,ID's, lengths, dqlths, etc. Lithology and other pertinent data will help invizualizing the problems
Make an operational plan that addresses items to look at before touching a fishand items to look at after touching fish (over fish or in fish). Play what-if?For example, wbat-if I can't circulate after attaching to the fish? Is my mudsafe to trip out with? Remember that well control and lost circulation are twomajor problerns that are closely associated with s$ck pipe.
As fishing job progresses, update drawing and fish description. Also indicateif fishing corditions are the same, better, or "more sticky.
It is a good idea to write notes of indications and reasons for carrying out anyoperation prior to doing the job, and then, zubsequently evaluate whether theoriginal thought was correct. It may well be that certain reasons for aparticular 'line of attack' may be valid at the time of proceeding, but whenmore information is available (as fishing proceeds), the original thought mayprove wrong.
Write a conclusion report and site interpretation of reason for occurrence, andsuggestions for funue prevention or improved fishing techniques.
Rule 2:
Rule 3:
Rule 4:
Rule 5:
Rule 6:
Rule 7:
Rule 8:
2022
Murchison Drillins Schools. Inc,
a?IIp!I,D,t,t-
IrIIr,r'rtf,a,Ittrtrtrtf,
ftrtrtrtIIIIIt-
!arTTt
)fi. STUCK PIPE (cont.)
Formulas:
Estimating Stuck Point (E.S.P.)
Method #1:
1,000,000 x stretchESP =
Where:
Factor x overpull (Vpipe in tension)
Factor =(r2)
(30) x (cross-sectional area of dp)or
EcD _ (stretch inch)x(30,000,000)x(cross sectional area)LDr - l, .
"""rp,rtt (tb)
Method #2:
735294xexW*ESF=
P
Where:e : Strerch (plpe in tension)
wde : Plain-end wt. of dp (without tool joints)
P = Overpull (prpe in tension)
Method #3: (Tapered drill string - below liner)
735294xexW, .''(' +)) L, Stuck point is in (or below) I,
( L, Snrck point is in upper string and the regular formula(Method 2) should be used (and the ESP recalculated).
: bngth of big drillpipe (above liner)
: I-ength of small drillpipe (in and below liner)
: Plain-end weight of big dp (without tool joinO
: Plain-end weight of small dp (without tool joints)
L=
Where:I fL
I fL
Lr
14
wrw2
2023
)O(. STUCK PIPE (cont.)
Method 4: Estimating Surck point
1) Meas're stretch in inches with the following overpull(s)
2-718 dp3-112" dp4-112" dp5" dp
Divide strerch by 3.5 and multipry by 1000 to give estimated free prpe.
Exarrple: 4-t12, 16.6, overpull 35,000 lbs.,Strerch = 20 inches
ESp = +, x tS = 5J00 fttJ.)
Rule-of-Thumb Economic Eguation
V= +C*Nn=T
Where: ND = Maximum number of fishing days
VF = Total replacement value of fish in hole, (g)
cno = Total estinated operational cost to redrill interval,(i.e., sidetrack), (g)
C" = Daily operational cost plus additional dailycost of fishing tools and senrices, ($/day)
Example 1: Wbat is the estimated snrck point (ESP) for this non-tapered drillstring? Given: Dp : 12,300ft. 5n, 19.5 lb/ft, Grade-nsu, )CI,'j%:el'ilf *":1#'i:TY;:;TIii,:'.tsi',#;:*''
--r-Ll
I--i --L2
-_l____il25,000 lbs.30,000 lbs.35,000 lbs.40,000 lbs.
2)
3)
20:4
Murchison Drillins Schmls. InrFEFEBFfDFFDtFFIFI
EFDFTFDFtFtFftFDFfDFtftFFFftDf'ltrD
XX. STUCK PIPE (cont.)
Example 1: (cont.)
ESP = 735294 x 38 x 17.93= 12,525 ft..
This number indicates that the pipeis sfirck in the bottom-hole assembly.If circulation is possible around drillcollars one of the differential stickingmethods shoutd be usd to free pipe.
Example 2: What is the estimated stuck point (ESP) for this tapered drillstring? Given: DP Ll : 10,000 ft; h : 2200 ft; plain+ndweight Wr = 17.93lb/ft; % = t2.3L lb/ft (5", 19.5 lb/ft, "S',)GI, NC50; and3-Ll2*, 13.3 lb/ft, "Xn, IF, NC38)
DC : 800 ft, 4-314" x 2" x 50 lb/ft; srerch = 4l inches;overpull = 40,000 lbs.
735294x41x12.31. ro,{r #) = r2,4r2 ft
40,000
il\L_
Since L(L2,4t2) is ) Lt (10,000),stuck point is at (or below) I-r. ThisESP (12,412) is in the DC (BHA).If circulation is possible approach thisstuck pipe problem as being causedby differential sticking and use oneof the methods for freeingdifferentially sruck pipe.
Example 3: What are the maximumnumber of fishing days based on the rule-of-thumb economic equation? Given: estimated replacementvalue of fish = $75,000; total estimated operational cost to redrillintervd : $75,000; the daily operational cost (rig, service, andtools) is $30,000.
No=75,000 + 75,000 = 5 days
This analysis should always be madebefore dritling people become"attached" to the fishing job. Stopafterreaching 5 days, no matterhowoptimistic the nnext-run" look's.
40,000
l l t lt) r.l
- t t l
i l t t
{il!
30,000
20zS
The formation test is used to gain knowledge of nrbzurface conditions related to pressures andreservoir fluid content @resence or absence of oil and gas). tn addition the DST should indicateformation characteristics with regard to permeability and fracnring. DST are also used toevaluate liner tops, casing shoes and perforations for presence or lack of communication. Thereare meny rules-of-thumb that apply to the key phases of a DST.
Phase 1: While nrnnine test tools in hole:
Rule 1: A drop in mud in annulus that corresponds with an air issue from the drillptpe is noted. The las 500 ft. of prpe should be pulled to locate leak.
Rule 2: A bridge is hit off bottom. If the tools cannot be worked through bridgeeasily, the tools should be pulled out of hole and a bit run.
Rule 3: A reduction in overflow (displacement) is noted, but no air issue i5 semingfrom the drillpipe. The formation is probably taking fluid and the runningin speed should be reduced to help eliminate pressure surges. Use triptank to monitor displaced fluid.
Rule 4: Correlate theoretical and actual displacement and note any difference.
Rule 5: Use fluid cushion fill-up valve to fill test string with c'ashion. (This avoidsaeration.)
Rule 6: Limit Preszure Differenfi Across Packer to approximately 2000 psi to:minimize plugging perforated joint; minimize sticking of anchor and;minimize losing packer seat.
r - F P - A P t " t-md -
Gr4w*) oo5,
Where: L-,0 = Irngth of mud in test string to give a certain differential
Fe = Formation Presnue
AP,"* : Differential Preszure Across DST Packer
MWrs : Mud Weight in Test String, ppg
Rule 7: Tension on test string lowers collapse resistance. Calculate effectivecollapse resistance based on tension force (load; hanging below point ofinterest (usually just above packer). This is very important if test stringis going to be filled with hydrocarbons (particularly gas). Use theformula(s) on Page 2l:2or the biaxial yield stress curve in the API RP7G.
2l:l
Mrrchisound[ius Sehools. Inc,
)Og. DRtr L STEM TESTITIG (DSn (cont.)
Rule 7: (cont.)
Where:
Effective Collapse Resistance
P. = (I-, - LJ@WA)(0.052)
Pc : Net collapse pressure based on Annulus mudcolumn and fluid column in teststring.
(Eff. Coll. Res = |
\
Where: /, =
f" Nominat)
2 )
Tension Force
,orf Average Yield )-\tvtininun Yield/
: from the RPTG: from the RPTG
*Aver Yietd (YJ*Min Yield (Y,,
P" Nominal
r***Yield Sn
[-ro
MwA
*Description
Grade "E"Grade "X"Grade'G'Grade "S'
t-ICrieu
: Collapse resistance from Table RPTG(Tables 2.3,2.5,2.7, or 2.9)
: Depth of Packer
: Yield Strength from Tables 2.4, etc. in the RPTG
: I:nglh of mud in Test String to give a certain differential
: Mud weight (ppg) in Annulus (behind Test String)
Average YieldY.
85,000110,m0120,000145,000
Minimum YieldY,
75,000 psi95,000 psi
150,000 psi135,000 psi
2lz2
** Yield (working) Strcngth = (Minimum Yield)(Cross-Sectional Area of dp)
Mnrchisnn flrillino Schools- f nc-
)XI. DRILL SIEM TESTING (I)SD (coor.)
Phase 2: While setting the packer or at beginnine of test:
RuIe 1: A sharp drop in the annulus denotes a packer failure. Pick up toolsimmediately to close main tester valve. Normally an openhole test willbe unsuccessful after this because the packer seat is usually washed out.A vertical fracnrc will also give the same indications.
Rule 2: A slow drop in the annulus denotes either a leaking packer or a loss toformation. If the loss continues after closing shut-invalve, it indicates thatthe loss was tq the formation. An accurate record of all losses during testshould be kept.
Rule 3: Slipping of the packer to reach "filre" bottom is noted. The initial flowshould be lengthened to compensate for this piston action or superchargeto the formation. The initial build-up curve on first closed-in pressure willnot be valid otherwise.
Phase 3: The'tester valve has been opened for initial flow:
Rule 1: A weak zurface blow is noted. The flow period should be extended to atleast 30 minutes, and the initid closed-in pressure build-up should beextended by approximate|y 50% of normai.
Rule 2: Slipping of packer was noted. Allow for zupercharging by flowing 10-15minutes longer.
Rule 3: A strong zurface blow is noted. The flow period couldbe shortened, but,as a general rule, it should be 30 minutes. If zurface observations indicatethe well is seming in, then the period should be shortened. Do not bringhydrocarbons to surface before daylight. Thecorresponding build-up, afterclosing well in, is also faster and this period could be shortened to 90minutes.
Phase 4: Initial Shut-in Period
Rule: Initial shut-in period should be long enough to allow bottom hole preszureto reach or approach static. One to two hours have proven to be sufficient,but never lsss thnn 30 minutes.
The tester valve has been open for second flow:
Rule 1: Experience should dictate the length of period. Consideration should begiven to zurface 'blow. n The weaker the blow, the slower the rate offormation influx and the longer the second flow period should be. Forexample, one hour of good flow is generally sufficient for good evaluation.
Phase 5:
D!I
2L:3
Murchison Drilling Schoots. Inc. C
(cont.) tPhase 5: : (cont.) t
CRule 2: It l% or more of Ir2S is detected, go into final build-up and reverse out Iduring final build-up.
IRule 3: If the drill prpe fluid load increases to the point that the hydrostatic head Iof the fluid column kills the inflow, the finat build-up subuo u" st"# C
immediately. C
Rule 4: For tests with. a weak surface blow tbroughout the duration of the flow Iperid, the tool must be left open lonler to sampte tn ror-.tilo ?effectively. Prior calculations snoun aeteinine rengtri or now peiJol' I
Rule 5: when chokes-are changed, it should be from small to large and not large =to small. The 3-719" hydroqpring has a 0.6n choke ana Oe i; ?hydroqpring has a 0.75". Discuss zurface choke sizes with tester uer- Iopening tool. Normally 3/g" and ll2: arcused. a
Phase 6: The final shut-in time (FSD. aI|
Rule 1: Should be at least eEral to the flowing time if an accump extrapolated Jpressure is to be obtained and if permeability changes nearby -; ; ;; ;ldetected.
;J
Rule 2: should be longer on row permeability formations /
aRule 3: Tools must not be moved during this build-up period. Be in the reversing -position before the build_up starts.
Rule 4: If an acid jop has been performed, allow the final build-up to be longer fbecause no damage is likely.
- ---e-- J
Formulas for FSI, Jq
1. Good flow aF.S.I. = Ll21 pinnl Flow Time C,
2. Averaee Well i
F.S.I. = 1 x Final Flow Time q
3. Poor s/ell q
F.s.I. = 2 xFinal Flow Time iCJ
2l:4 qe/
Murchison lhilins Schmls. Inc
EFEEEEEBFtFtFtFFtDFFI)DtrlfItlr-)
I)trlrt
ICKI. DRILL STEM TESTING (DSn (cont.)
Phase 7: Unseating the packer and reversins out:
Rule 1: On hookwall tests, neversing should be done during final shut-in. Rotateto reversirg position with control head mrnifo[d valve closed.
Rule 2: Pull that can be safely be exerted on the drill prpe is drastically reducedwhen the drillpipe is not filled with a fluid of equivalent density to that onthe outside of the pipe @iaxial loading).
Rule 3: On openhole tests, it would depend on hole condition, but as a generalrule, reversing would be done before unseating the packer. If lostcirculation is expected after unseating packer, it would be better to reverseout before unseating packer. This should be determined ahead of time.
Rule 4: Be sure the DCIP valve is in reversing position before unseating packerbecause weight is reErired before it can be rotated.
Rule 5: Line up two (2) pumps on annulus before starting to reverse out becausemud will fall in ennulus and flow into drill pipe. On tests where influxof formation fluid has been low, allow pipe to fill against a closed inzurface valve and observe pressure reading on head before continuing toreverse against back pressure held on choke manifold.
Rule 6: After closing B.O.P.'s, the reversing pressure should be restricted to aslow as possible to prevent lost circulation.
Rule 7: Acctrate measurements and descriptions of all recovered fluid is importantto test interpretation. On a low producing well, the flowing pressure isindicative of drill pipe fill up and the sun of hydrostatic pressures of therecovery should eryal the frnal flow pressure. The recovery has to bemeasured closely and the densities checked. All fluids or mixnrres offluids should be described.
Phase 8: Pulling test tools out of hole:
Rule 1: Make zure annuluS and drill pipe are bdanced before reversing out isstopped.
Rule 2: If hydrocarbons have been tested, do not pull out after dark. Pulling tocasing shoe would be permitted after reversing out.
Rule 3: Warch annulus closely. Any upward movement after pipe stops should betreated as an emergency. Make sure hole is taking correct displacement.A trip tank should be used.
Rule 4: Use mud saver and cap all oil-filled stands.
2l:.5
Mmchbon Drilling Schools. Inc.
)Oil. DRILL SIEM TESTING (DSTI (cont.)
Phase 8: hrlline test tools out of hole: (cont.)
Rule 5: Rate of loss (if any) should be determined before pulling out of hole.In cases of heavy losses, an I.CM pill should be pumped in annulus.Reduce losses to a safe level before pulLing out of hole.
Example: The FormationPreszure is estimated to be 6800 psi. To limitdifferential pressure to 2000 psi across a packer at 10,000feet, how many feet of 13.5 ppg should be put in test string?What would the net collapse pressure be at the fluid depthinside the drill string?
r _ (6800-2Lrnoa=f f i=6838feet
APn*.. = 6800 psi - (6838X13.5)(0.052)= 2000 psi
P. = (10,000-6838)(13.5X0.052) :2200 psi t
What is the effective collapse resistance of the given teststring just above the packer and if the test string was full ofgas, with 500 psi flowing pressure, would it withstand thecollapse pressure of the mud column behind the test string?Given: Test String : 10,000 ft., 5, 19.5, Grade nEn, XII,prem class; Anchor assembly below packer creates a tensionforce of 50,000 lbs; Yield Strength (working) : 31 1,540 lbs;mud behind the test string = 13.5 ppg; Packer Depth =10,000 feet (7000 psi hydrostatic).
Example:
z- 50,(x)0 = O.142
311.s40 r.!l)\72)
l z rnnT!- ' lEff. Coll. Res = l+l/+ - 3(0.142)2 - (0.r42)J
l '2r: 6514 psi
The effective collapse resisance plus the flowing pressure(6500 + 500) is about equal to the mud hydrostatic (7000psi). The weight of gas was ignored. I would recommendusing a higher grade drillprpe . The effective collapse at3L43feet, the top of the mud in test string when the packer wasset, is approximately 3300 psi (Tensile Force of 204,000 lbs)and the net collapse pressure (from the annulus mud) is2200psi. Collapse is generally a problem in the deeper part as thehole (near bottom) and that is tnre in this case.
2l:6
Murchison Drillins Schools. Inc
)OilI. DRILL STRING DESIGN
Drill string desrgn is more imporAnt bday rhan ever before because bits are designed to lastlonger and therefore the drill string is zubjected to longer rotating hours between make-up andnormal trip inspection. Deeper wells are requiring a closer look at tensile, torsional and coiapseloads. Drill string failures lead to undesired trips and many hole stability problems related totrips. The following rules and formulas appty to drill string design.
Rule 1: Design drill collars and bouom hole assembly to: effectively load the bit; providestiffness to prevent dog logs and keyseats; imFrove bit bearing life and overall bitperformance; produce a smooth bore full size, hole (effective hole diameter);minimize barmful vibrations; minimize drifling problems and; minimize pressuredifferential sticking.
Dc"to = #"*L
*L*t rl =DC"i, - [(La.rxDC"o) + (Lu.rrxDC"o)l
*Note: In Tapered DC strings the bottom sections(S1, 52) are generally chosen (not calculated)and the 2nd or 3rd section calculated.
wor L,-- "BHA
w BFxDCo"La" =
BFxSFxDC*"
_ (65.44 - lvf$r)65.4
SF=(100 - %sD
100
DCI\nfTsM = 2.61 (DCOD2 - DCID2)
DCSfTsp = DCSII* - (DCT/T'*, x 0.039)
ho=(Ld" - L.d")DCYm
Ir%r
NP = w'o-B'DCrn x BF
W.O.B. = La" x DCo, x BF x SF
w.o.B.
,)
It
22zl
)XII. DRILL STRING DESIGN (cont.)
Rule 1: (cont.)
Where: DC*
w.o.B.
Wrno
W"soc
BF
SF
VoSF
Lo.
DC*rt
sF^ = 1oo - fcw.o.g.l * rool"
t @C.r)xBF J
DQ = 107 (DcoDf
MEHD=$shi lDc@
MPBIIDCOD = 2 (Cas. Coup. OD) - Bit Size
t . ' l
IlC = 0.0982 I PoD" - PID4 |LPoDI
UC Ratio _ VC Large Pipe'
VC $mall PiPs
: Air weight of drill collars (the firststep in designing a tapered dc assembly
= Weight on bit
= Weight of BHA desired below jars (which isequal to weight on bit plus jar tension) lbs.%*:WOB+JT
: WOB * JT (correcled fog deviationtg-acqoun! fgr'pa4-gf weight supported by borehole
walt)cosc
: Buoyancy factor
-- Safety factor
= LO%, l5%,20%, e tc .
= Length of drill collars (one OD size calculatedin mud)
: Weight drill collars, lb/ft
22:.2
AD,a
Murchison Drilline Sclrools- f n
JD )OilI. DRILL STRING DESIGN (cont.)
,,
- Rule l: (cont.)
It,)
a,
HWm = Heavy wate drill pipe weight, lb/ft
MW : Mud weight, lb/gal
DCWTSM = Drill collar weight for smooth DC, lb/ft
DCWTsp = Drill collar weight for spiral DC, lb/ft
JT = far bnsion (all dri[ine iars should benrn in tension)
NP = Approx. neutral point
Sn = Corrected safety factor
I*" : Maximum desirable length of drill collarsto be run, ft
DCOD = Drill collar OD, inch
DCID : Drill collar, ID, inch
DC, : Dritl collar torque (approximate, based on usingAPI approved dope)
MEIID : Minimum effective hole diameter, inch
MPBHPCOD = Minimum permissible bottom hole drill collaroutside diameter
Bit Size = Bit outside diameter, inch
Cas. Coup. OD : Casing coupling outside diameter inches(i.e., 9-5l8n cas. coup. : 10.625")
IIC = Stiffness factor (if you double the diaureterits stiffness increases 16 times)
I/C Ratio = Comparing stiffness of two (or more) OD pipestbat screw together. The ratio between twodifferent pipe sizes should be kept below 3.5
2223
(Uurclitnn nming Sctools. tnc.
I)OilI. DRILL STRING DESIGN (cont.)
Rule 1: (cont.)
POD
PID
Example 1: Design leagth of drill collars. Given: weight on bit desired = 40,000 lbs;dc = Gll2x2-t3ll6 x 91 lb/ft; mud weight = 14 ppg; BF = 0.786; safetyfactor : 15%
I - = oo'ry l-h' = 65g feetD&- o :zg6*o.E5x9 l .
Example 2: Same as above except desrgn drill collars to give 6000 lb desired jar tension.
r - (40'000 -= P) = 643 feet (position of drilling jars fromL'& - -0166
* ,, bir. An additional lo,000lbs of dc wr(a-5 joints) would be run for jarringweight.
Example 3: Same as example 2 except the well is directional aM hevi weight drill prpeis zubstinrted for part of the required bit weight. Given: max dc length =2W feet; IfW : 49.3|blft (5 inch IIW).
La" = 643 (ex.2)
T--. = (e3 - 2n)91 = glg feet"Hw - -qg.s
Note: 200 feet of dc and 818 feet IIW (approx. 26 n of HW) would berun below jan. An additional six to eight joints of rrw would berun for jarring WT above jars.
Example 4: Sane as example 2 and 3 except the weight BHA is corrected for deviation.Given: draft angle : 25o (cos = 0.9063).
W*^.. = (40'ooo + 6ooo) = 50.755 Ibcos 25o
: Pipe outside diameter, inch
= Pipe inside diameter, inch
IIIIIIIttttttttttttttIItIIItIIIIIIIIIIIII
L&=
I,l'*
ffi =Tlofeet
_ (710 - 200)9149.3
?2:4
= 941 feet (30 Joints)
Murchison Drillinq Scbmh. Incl'-FFFFFFFbFFFbIthFbFIFIttsFEfttttFTftFlIlrFFftrItITIllrE-
It
)OilI. DRILL STRING DESIGN (cont.)
Rule 1: (cont.)
Example 4: (cont.)
Note: Below the jars the BHA would consist of 200 feet of drill collars,94I feet hevi wate dp (approx. 30 joints). Above the jars anadditional 6 to 8 joints of hevi wate drillpipe (8-10,000 lbs) wouldbe run for jarring weight.
Rule 2: Crenerally speaking,. more non-magnetic collars (monel) are needed whendrilling a high angle directional well east:w€st than north-south.
Rule 3: A stabilizer should not be run below motor. If needed for control placestabilizer at least 60 feet above the mud motor.
Rule 4: With mud motors use 1 to 2 stands of drill collars. Match bits to mudmotor.
Rule 5: In directional holes use more heavy walled drill pipe (Hevi-wate) and lessdrill collars (approximately 200 feet drill collars). See calculations belowRule 1.
Rule 6: The most efFrcient and practical way to input a sizeable negative side forceto the bit is to use a pendulum tlpe assembly. ::.
Formula: F, = (U2)(DCvm)G,r)@FXSin 0)
Where: Fp : Pendulum force, lb
l- = Tangency length, ft (tangency length is the distancefrom the bit to the next point of contact).
Example 1: Calculate the maximum pendulum force (Fr). Given: l2-ll4 inch bit; DC- 20, 7n x 2" x 120 lb/ft; mud : 10 ppg; Tangency point is roughly 30feet from the bit; survey angle : 5oi BF = 0.85.
Example 2: Calculate the maximum pendulum force F,
Fp = rl2 (120X30)(.85)(Sin 5)
FP : 133.4 lbs
Example 3: You had to increase the mud weight to 15 lbs/gal. What is the newpendulum force?
BF = .77
22:5
Murchison Dri[ine Schools. Inc.
)OilI. DRILL STRING DESIGN (cont.)
Example 3: (cont.)
Fp = 133.4 +* < - apply new B,<- remove old B.
FP : 120.9 lbs.
Examole 4: You have placed a stabilizer 60 ft-from the bit. IVhat is the new pendulumforce for 10 lb/gal mud?
Fp : L33.4 (60) <- aPPIY new I.
(30) (- remove old I.
FP = 266.8 lbs
Example 5: You have anothe, **"y which indicates the new inclination angle is 15o.What is the pendulum force for the case above, i.e., Ex. 4?
Fp = 266.g (Sin 15) <- aPPIY new 0
iGF) <- remove old 0
FP : 792-3lbs
Example 6: You have increased your collar size to 9' OD by 3" ID. What is thependulum force for 10 lb/gal mud at 5o inclination? Take the tangency pointto be at 30 ft.
[48e]Ke)2 - (3FI
rs2 rblft
.85
Rule 7:
Fp = 1/2(192X30X.85)Sin 5"
Fp = 213'4 lbs
Stabilizen can be used: as Fulcrum (lever) to build angle; as a tangent forpendulum control (create negative force); as a neutralizs to counter thereaction above, i.e., a packed hole assembly; as a centralizer to keep wallCOntaCt tO a minimUm.
The smaller the collar size in relation to the hole size. the more the holetends to build and walk.
Rule 8:
22:6
w=fr' 576
W"=
BF=
IOilI. DRILL STRING DF,SIGN (cont.)
Rule 9: Effect of weieht-on-bit and rotary speed
Increase WOB to build angle
Decrease WOB to drop angle
Slow rotary, increase WOB - hole walts right
Fast rotary, decreases WOB - slows right_had walk
Small holes, (less than 8-Ll2 n.), the higher 1trs angle the less the walk.
Example 1: The following bit cotrse is most t)"ical for a tubine drilling a directional hole(no benr sub). 'il-
Exarnple 2: The following bit course could occur while drilling a directional hole withnubine and increasing the rorary speed from 10 RpM to 100 RpM.
I@RPM
Bit performanpe in directional drilling
Bits tend to nwalk updip" until the formation dip reaches approximately45 degrees. when dip exceeds 45 degrees, theytend to *alk "down-dii. "
Cone offset from center on tricone rock bits tends to increase right-hand walk.
nTrue Rolling" bits without cone offset decreases right-hand walk. Cone offsetis desirable, (it allows better slganing), in most ."rer due to the increasedpenetration rates.
Hand Walk
,@t i
tncreased ttl
Rotary Sgeed 'jFrom lOto I
Rule 10:
Target
aJr-*Ha'rdwatk
,:l)*.",,Handwa*
Target
?'!.-"Trgret
,?!
tI'IIJ'IJ'-
tr'l'
Right HandWalk-+\
2227
Murclison Drinins Senoo|s. Inc.
ICXII. DRILL STRING DESIGN (cont.)
Rule 11: General Rules
Rule 12:
1. Packed2. Pendulum ' -3. Belly4. Mud motor -
Don't bring angle back any faster then it got off.
Holes which are off pele rhan 3 degrees are normally considered to bedirectional wells.
Don't drill more hole than you can k*p; hole cleaning is extremelyimportant.
Topdrive units help eliminate keyseats.
Basic boftom hole assemblies
aIIaTaaIaI;
taaaaIai;
!!-
IIIIIIIIIIqJ
hold angledrop anglebuild anglebuild/drop/nun
Note: See following general responses assemblies.
2228
Murchison llrilline Schools. Inc
u{t( tst
ai.l.pFFppppp!TppIEI'
ItrtII'I'I'f),,
r)rtrta,I'Ittr'tl'Itt,tl',)
,D
IOilI. DRILL STRING DESIGN (cont.)
Rule 12: Basic bottom hole assemblies (cont.)
VAR IOUS BOTTOI I HOLE ASSEI{BL IES I I ITHGENERAL RESPONSES UNDER IDEAL CONDITIONS
(NO HOLE CURVRTURE EFFECTStrRprnr.l-si rRo,,
RSS0rELllto.( l ,
(2t
( l ,
( | l
(5)
(E '(? t(t)
(8 '
( l0)
( l1 ,( t2,
( t3t
RtsP0ltsEBUn"0
8Uil.0
SUITD
3UII.D
IUILO
sUIIOBUlr,.0
ITLRIIYIIntsP0[s€sTRtx0n
l0
t' t
7-3
?-s5-t1-28-2
I
t0
II
5-t
t-8
l0
5-10 (smttntt!, 0R0? ll0Lts CRll l€
SIIIER ltrnt{ rtgt(t?l DRgp t Butt3(I8I DROP(RI HICHTR IIIC1)TEUILD
RilD/0R(RT L0|ER lflCtt(I9I DROP OR BUITD(HIOHLI
DEPTXDEIT $ COLTRR OO'.10 ls .Drt Hlotrtsl R[0 I llrt LorEsl
Bulto(oRoPs uromcttlnlfl ctRculslnflcts,
3UlL0 0R 0R0P
Hot0
Hot0Hot!
IIOLD
InRR 3tT lll fn$ r0 ttRt)lHSslestuftn ocE 0f srRglLtlER)
D* 6\
F
>I lss
x-3!---+-xrst80!30t30x
>I-3!-*-!q+ 3\
>ts!
ff
ltot.0
OROP
Note on Drop Assembly No. (15) From Creneral Response Assembly List
Holes larger than 9-718.
1. Run stabilizer at top of third dc.
2. Make zure the bottom three dc are the largest you can use.
Holes 9-718" or sqaller
1. Run stabilizer at the top of second dc.
2. Make sure the two bottom collars are the largest you can use.
> 6=oi4 ' I= ==60-t0' 3 0 0 3 0
22:9
Munchison Ihilling Schools. Inc.
)XII. DRILL STRING DESIGN (cont.)
Design length of drillpipe based on overpull and slip snrshing. choose thesmallest length between the trro methods.
Y. x 0.9
m
(DPAW)(BD
M.O.p . = (y .x0 .9 ) _M"
'Where: r.@* = kngth of drillpipe that can be used basedon a margin of overpull (M.O.P.)
M.O.P. :
Loo." :
(Y.x0.9) - (M.O.P.) - (WT^)(DPAW)(BD
Rule 13:
following tables.
Grade nEn, )CH,
22210
uI^ Looe(? )
Formula(s):
Luno, =
l r .0 .P.
,"rfr11l
5'dp
4-u2', dp
3-112" dp
: 100,000 lbs
: 100,000 lbs
: 75,000 lbs
Y,
kngth of drillpipe that can be used based on slipes5hing (Sh/Sr). The ratio of hoop stress to tensilestress (Sh/Sr) constants can be found in the
Minimum yield strength based on pipe grade andwear classification. This number is uzually takenfrom RPTG tables and then downgraded by t0%by multiplying the minimum yield by 0.9. Anoption to this is to take the inspection report,showing ffus 1s64ining cross-sectional area, andcalculate the working strength from this; i.e.,92%remaining cross-sectional area h 5n, 19.5 lb/ft,
NC 50 drillpipe.
DDDDDDrtJ)rttt!ttttt
XXII. DRILL STRING DESIGN (cont.)
Rule 13: (cont.)
Working Strength = 0.92 [(Tube Of,P - Tube [ff)0.7854 x 75,000 lb/sq in]
Grade Min Yield ffJ
GradeE : 75,000psiGradeX = 95,000psiGrade G 105,000 psiGradeS : 135,000psi
W.S. = (min yield YJ x (cross-sectional area of tube)
WTA : The buoyancy weight of all pipe hanging below the pipebeing designed. WTo : (Air Weight of pipe) (BF).
WTB = Total buoyancy weight hanging below top joint of drillpipe being calculated for M.O.P.
DPo* = The tube weight plus the upsets averaged into anapproximate weight per foot; i.e.:
OD Nominal Connection DP^*(ins) lbs/ft Grade Tvpe 0b/ft)
5 19.5 "E" )(H 20.995 19.5 'X" XH 21.445 19.5 ncn xH 2r.925 19.5 'S" XH 22.ffi
4-Lt2 t6.6 'En IF L7.gg4-Il2 16.6 'X' IF 19.344-Ll2 16.6 'G" tF 19.344-u2 16.6 'S" IF 13.613-u2 13.3 "E" IF 13.773-Ll2 L3.3 'S' IF t4.69
BF = Buoyancy
EE_l los.u- tvfw(ppdl lDL -t ov,o 1
Sh/Sr : Ratio of hoop stress to tensile stress acting on drill pipein the slips (see Slip Crushing constants below); i.e.,5' DP, 16" slip, 0.08 coefFrcient of friction : 1.42;4l l2 dp : 1.37;3-Ll2 : t .28.
22:Il
IXII. DRILL STRING DESIGN (cont.)
rltlrux llllo th/sr tro ptrT.ra siLlp cnuslllo
slipL.lgth
co.ffici.Dto f
lrl!araraGIa.d
.(,6
.o8 .
. t o
. t 2
. 1 1
4 . 3 5a .oo3 . 6 8t . a 23 . 1 8
L . 2 7t . 2 st . 2 2l . 2 rt . t ,
l . 3 a1 . 3 1L . 2 aL . 2 6L . 2 4
t . a 3I . 3 91 . 3 sI . 3 2I . 3 0
1 . 3 0l . { 5t . a t1 . 3 8l . 3 a
1 . 5 81 . 5 2t . e 7t . a 3t . a o
1 . 5 5I . 5 91 . 5 4I . 4 91 . 4 5
1 . ? 31 . 6 61 . 6 01 . 5 51 . s o
. 05
. 08 r
. t o
. L 2
. l {
a . 3 6a . o o3 . 3 83 . a 23 . 1 8
1 . 2 0l . 1 8l . 1 51 . 1 5r . l a
t . 2 {t . 2 2r . 2 0l . l 81 . 1 7
1 . 3 0I . 2 81 . 2 51 . 2 31 . 2 1
l . t 51 . 3 2, . 2 9t . 2 7I . 2 5
I . a r1 . 3 7l . 3 a1 . 3 11 . 2 8
l . a tl . a 2t . 3 tt . 3 5r . 3 2
1 . 5 2t . a 7l . a 3t . 3 9t . t 6
*A cocfficicnr of friction of 0.08 is typical for lubricard stips.
Desien Requirements:
Max. Weight on BitJarring Tension (JT)
= 40,000 lbs= 6,000 lbs
DC to Give Janing WT : ffi ftIfW to Complete Jaming WT : 10,000 lb TOT
(less 2 dc)
Available Drill String:
DC : 6-112 x2-l3lt6 x 91 lb/ft, NC46DP : 5, 19.5, Grade nE", XlI,NC50, Prem. Class
5, 19.5, Grade nxn, )CfI,NC50, Prem. Class5, 19.5, Grade usu, XlI,NC50, Prem. Class
HW = 5n x 3' x 49.3lb/ft, NC50
Mud Weieht : 17.0 ppg
Buoyancy Factor = 0.74
1.0 Drill Collars: Lr. = (40,000 + 6000)
Example:
IIItIattttttttJ;
;
aaiIa:
I;
TJTIa!II:
!IttlEaaa
(0.74 x 91)= 683 ft below jars
22:L2
*DC TOT = 683 ft below jars + 60 ft above jars = 743 ft.
,)
,D)
7't,brtI,DItJDr'rtI'f,tttDrttfr)DDItf)t,,)
rt,tDtDJ'Dr'JDttttrtrt
)OilI. DRILL STRING DESIGN (cont.)
2.0 Hevi-wate DP: I** - 10'000 lbs-(6o x 91 x 0'74) = 163 feet(49.3 x O.7a)
Round off HW to 6 JTs = 186 feet
*Note: On a directional well or a well that differential sticking is acolrcern the drill collars may be shortened to approximately 200feet and the heary walled drillprpe increased to give Jar Tensionand Jarring Weight.
3.0 BHA Summary:Irngth : 743 ft(DC)+186 ft (HW) : 929 feet
Air weight = (743x91)+(186x49.3) = 76,783 lbs
Buoy WT = 76,783x0.74 : 56,819 lbs
4.0 DP Design. Section 1 (Above BHA)5, 19.5, Grade E, XlI, NC-50, Prem Class, Ym = 311,540 lbs
T = (311,540 x 0.9)-100,000-56,819 = 7.9g9 ftLdp"p - eO.g_OJ4)
- ' , '
(311,5fl_x 0.9) _ 56,819Lep,"=
# =9,093ft
Use the smallest length (therefore desigu is limited by overpull).Irngth of Grade E : 7.989 ft
5.0 Summary: BHA and Section 1 (E) Buoy IVeight
BHA Weight = 56,819 lbsGrade nEn Air WT = 7,989 x20.9 = 166,970 lbGrade 'E' Buoy WT = 166,970 x 0.74 : 123,558 lbAccumulated Buoy WT : 56,819 + 123,558 : 180.377 lb
6.0 DP Design. Section 2 (Above Grade "E" dp)
5, 19.5, Grade uxn, XlI, NC-50, Prem Class, Y. : 394,600 lb
r - (394,600 x 0.9) - 100,000 - 180,377 - A,rnl €rLdpop -
eL4 - a?4) - -"LL LL
222L3
Murchison Drilins Schools. Inc.
)OilI. DRILL STRING DESIGN (cont.)
6.0 DP Desien. Section 2 (Above Grade 'E' dp) (cont.)
[1rg+,600 * o.g) _ rro.rrr]Lapu"=t%]=+wzr,
Use the smallest length (therefore desrgn is limited by slip grushing).I-en Grade X = 4.402 ft
7.0 Summary: BHA * Section I * Section 2 Buoy S/T
BHA Weight : 56,819 lbGrade nEn = 123,558 lbGrade nxn Air WI : 4402 x21.4 = 94,203lbGrade nXn Buoy WT = 94,203 x 0.74 = 69,710 lbAccum. Buoy WT : 56,819 + 123,558 + 69,710 = 250.087
8.0 DP Design. Section 3 (Above Grade .X" dp)5, 19.5, Grade S, )CI, NC-50, Prem Class, Y, : 560,760 lbs
Loo* _ (560,760 x 0.9) - 100,000 -250,087 = 9p85 ftQ2.5 x o.7a)
l(seo,lg x 0.9\ ^F^ ̂^- Il l - r - ,50 .087 I
, _ l \ t .42 ) |-@ -
l- = o,32o nl- L Q2.5 x o.74) I
Use the smallest length (therefore design is limited by slip srushing.)I-ength of Grade S : 6.326 (max)
9.0 Summary: Total I-eneth & Buo)tancy Accum. Weight
DC Irn = 743 ft.HW I-en : 186 ftGrade nE" I.en = 7989 ft.Grade "X" I-en : 4402 ftSubtotal Len = 13,?20 ft.Grade nS" Len = 16,000 - 13,320 = 2680 ft*Total DS = 16.000 ft
Accum. TOT WT : 25O,087 + (2680 x22.5 x 0.74) : 294.709lb
* Note: Only part of calculated Grade "S- drillpipe was required to reach16,000 ft (a deeper depth could have been reached based on Grade "S"working strenglh).
IqsrlJ
14,tl4ltl+l4I4JI4+14ccc44t4I1ccIIqqqqaIrfaJ,qd
22:14
Murchison Ihillins Schools. Incl''FEFFFFFFFFFtsbFFFItftItItFfrtFFItItItIADrI',tt,aI'
IOilI. DRILL STRING DESIGN (cont.)
10. Marein of Overpull Check (M.O.P.)
Grade nE' DP = (311,540 x 0.9) - L80,377 = 100,000 lb (ok)Grade 'Xn DP = (394,600 x 0.9) - 250,087 : 105,000 lb (ok)*Grade "Sn DP = (560,760 x 0.9) -294,709 = 209,975lb (ok)**
*Note: This section was limited by Slip Crushing, therefore the M.O.P. is grearer.
*'tNote: This indicarcs the hole could be drilled to a deeper depth (approx.19,000 ft). The driller is always limited on overpull to weakestsection in drill striqg, which is Grade "E" (100,000 lbs).
11.0 Summary of Desien
Item Description kngth Air WT BuoyWT
AccumWT
M.O.P.
DC: 6-l l2x2-13 I 16x91, NC50I IW:5x3x49 .3 ,NC50
743186
67,6L39,t70
50,0346,786
50,03456,819
BHA Summary 929 76,783 56,819 56,819
DP:5,19.5, Grade nEn, XI,NC505,19.5, Grade 'X', )CI,NCSO5,19.5, Grade nS', XII,NC5O
7,9894,Q22,680
L66,97094,20360,300
t23,55869,7t0M,622
190,377250,087294,709
100,000105,000209,975
Totals: 16,000 ft 398,256 294,709 294,709 100,000Limited
22:tS
Murchison Ihilline Schools. Inc;a2?l,7ItJD22a,a,at,ttI'IItI'IIIrtr,DJ'
TIb!b!pttt,ItFFPtjttt
Iililtr. LOGGING RTJI,ES FOR DRILLINGT
Common tJpes of well logs can be a valuable tool for all drilling personnel. Good drillingoperations are dependent upon the ability to plan ahead of the bit and accurately predict whatcombination of drilling variables will rezult in the most efficient peneffition of the formationsencountered.
Most log analysts are experts in defining exact intervals in the wellbore which contain pay, andperforming precise calculations which indicate the saorations of water and hydrocarbon withinthe rock. However, logs are also one of the best sources of information available to identify ttreproperties of the rocks themselves. Since most nrbsurface rocks contain saltwater and thesalinity of the water uzually does not change drastically over short intervals, most of the changesin the response of a log parameter are due to the character of the rock. There are exceptionszuch as fresh water bearing roclcs or hydrocarbon bearing rocks.
Rule 1: Study the trend of the logging curves
Since drilling people are interested in the hole from top to bottom, they are interested inthe entire log, and not just select intervals. Rather then performing many calculationson a small intenral, the drilling person is interested in trends of vdues which indicate thevariations in drillability he can expect from the formations to be penetrated.
Rule 2: Use logs to assist with bit selection
Using bit records and lois, poor bit selection can be avoided. Suppose the contractor rana J4, and drilled the interval at 14 ft/hr. On another offsetting well, an X3 was usedat this depth and averaged 35 ff/hr. Without the logs on the intervals from both wells,we cannot definitely say we should also use an X3. But if the two logs indicate roughlythe same dritlability for the trro intervals, we would expect that an X3 would at leastdouble the penetration rate over the J44 providing other factors are equal. This similardrillability would be indicated by approximately the same percentage of sand-shale, andby similar resistivities of the sands and shales . If we anticipate the same sequence inour proposed well, we would also use a series l-24 bit, unless there was otherinformation to indicate that some other bit might be superior. We could also expectpenetration rates of approximately 35 ff/hr.
Although it is possible to do some optimizing of drilling variables without logs, theirproper use makes it possible to do a much more effective job of planning, monitoring,and post appraisal of drilling programs. Common drilling data, such as bit records, andpenetration rate data, zuch as TOTCO's, can be misleading without forrration data. Ashort tooth bit nrn in anticipation of harder formations will make the penetration ratedrop, which is often misconstnred as indeed drilling a harder formation. The converseis also tnre in that a long tooth mill or button bit is run when there is a major formationdrillability change, anticipating only "a few hard stringers." Such costly mistakes canoften be prevented by the simplest examination of a log.
Ref. 8: Murchison Drilling Schools, Drilling Manual.
23:l
Murchison lhilline Sc]ools. Inc.
IOfltr. LOGGING RT LES FOR DRILLING (cont.)
Rule 3: Use logs to help olan mud proeram and to post appraise mud program
Mud recaps, although a valuable post appraisal tool, can be misleading withoutconsulting a log. Mud heating problems can frequently be prevented througbpretreament or a change in mud t'?e after determination of the lithology froma log. Mud weigbts used in offset wells are often unnecessarily high, and porepressures determined from logs can be used as a guide to reducing mud density.A caliper log will help evaluate whether the mud maintained hole stability.Hydraulics, however, may be the cause of hole enlargement.
Rule 4: Use offset logs to "drill ahead of the bit"
Ings can also be applied to solving other drilling problems. They can indicatethe offending formations when torque, drag, ledges, or tight qpots occur. Holeproblems s;uch as washout, sloughing, lost circulation, and differential stickingcan often be better resolved after examination of the offending formation usingwell logs. For instance, if you were looking at an offset log correlationindicating the driller had just drilled a permeable sand, the driller can be told tokeep the pipe moving at all times while the bottom hole assembly is across thepermeable zntrc. The driller could be especially alerted to have prpe movingwhen engaging the pump.
Keep a rate of penetration plot on same scale that log is recorded on: i.e.. 1 inchper 100 ft. erc. Use this to correlate with anlr porosiw log (neutron. density. orsonic) or one of the other logs.
During drilling o'perations, a correlation of penetration rate to the lithology curveof a log frequently helps the operator keep up with the depth in relation to thegeologic sequence. Virnnlly every well drilled has new tops picked for someformations. Many times the correlation betrreen the drilling rate and the log isadequate to confirm or disprove the predicted formation tops, and the drillingprogram can be adjusted if necessary. These tops indicate thinned or thickenedformation sections and the information can be used to plan a more practical andeconomical bit and mud program, tailored to the anticipated formation.
Use logs for optimizing drilling program
The normal logs, commonly run to locate and evaluate potential pay sections,are very useful when used with other data as part of a comprehensive drillingprogram based on improved mud and hydraulics, newer bit qpes, predictedformation tops, and optimum weight and rotary conditions. The logs mostcommonly used in drilling operations provide information about the formationtype, drillability, and the bore hole condition.
Iaa;
CI€
aRule 5:
Rule 6:
a;
Iaaataaa!ITItITIttlJJ
2322
Murchison Drillins Schools. Inc.F.?2FFf.lrlrFI'pItrtI'rttrtrtI'ITItttItD,tDrtrt!ttt!!ttIttbt!
)OilII. LOGGING RULES FOR DRILLING (cont.)
Rule 7: Calculate the percent shale. in the section of hole to be drilled. before finalizine bitselection
In soft formations (top hol$ sands/shales can be drilled with same bit. Vary type bitwith formation hardness starting with an API class of 1 1 1. Refer to resistivity curveto estimate bardness (1-2 ohm-m would be soft).
Series 4 & 5 - Designed for shale. Also PDC bits are designed for high percentagesof shales.
Series 6 - Assumes formations contain [sss rhan 30% shale.
Series 7 - For hard sandsilimestone. Irss th^n L0% shale.
Series 8 - For dolomite/limestone and chart.
Series 7 & 8 cannot handle high shale.
Also use the resistivity, conductivity, or one of the porosity logs to estimat€ formationdrillabilitv.
Formula:
or dt^^t^ _ (G.R. at Point of Interest)-(G.R. Lowest Reading in Clean Sand or LMST)To JIlSlO =
(G.R. at Highest Reading in Clean Shale)-(G.R. Lowest Reading-Sand)'Where: G.R. : Gamma Ray Log
Example: Calculate % st:nle. Given: GR at point of interest : 110; GR at lowestreading (clean sand) : 30; GR at highest reading (clean shale) : 135
% shale = S. i9^l = 0.76 (76d)(135 - 30)
Therefore, a bit that will handle shale must be selected. (A bit ttrat isRPM and hydraulic reqponsive--not weight responsive.)
Rule 8: Use the logs on the right hand side of depth scale to pick changes in drillabilitv
ln non-permeable zones when the logs shift to the right the formation is harder andwhen they shift to the left the formation is softer (usually more porous). Porosity logscan be used even when the zone is permeable but not the resistivity logs because theyare influenced by fluids which counteracts this trend.
Use the conductivity, resistivity and porosity logs to estimate formation drillabitity(functions of porosity and perrreabitity). Pick a bit that will drill a multiplicity offormation drillability intervals.
2323
Murrhison l)rillins Schools. Inc.
XXItr. LOGGING RttLES FOR DRILLING (cont.)
Rule 8: Use the logs on the rieht hand side of depth scale to pick changes in drillabilitv(cont.)
Use SP and GR logs to detect percent shale and non-shale. The points farthestto the right can be used to draw shale baseline. Shale does not respond to bitweight (RPM responsive).
Sandy shale, limey shale and pure shale can be differentiated by observing thedeflection of resistivity and conductivity logs (normally deflection is to the rightof the log). ff hard streat<s 31p making the bit wear under gauge, the Series 6could be used with 50 to 80% shale if mud condition is excellent so that the bitcan respond to bit weight.
Series 7 and 8 can't handle high percents of shale. Good mud (or bad) has agreater affect on a Series 6 bit then a Series 5. Whether Series 6 will drill willdepend on mud condition.
Permeabitity affects formation drillability depending on the condition of mudGood or bad). With poor mud the soft formations become less bit weightsensitive and become RPM sensitive.
c-GlqctJqrlqJ!qqqqiqa,a,qa,J1I;
Iqdd.lqdiiqqrlqrlrIqdil
I
Porositv affects formation drillability, regardless of mud.
Shale gives the most problem in drilling and hole stability.
The right side of depth scale on logs alnost always can be used to estimateformation drillability
The left side of depth scale on logs is used for estimating shale or non-shale.
Logs ttrat car.v a radioactive source should be nrn after evaluating hole conditionwith one of the non-radioactive (source) logs.
If a source log becomes stuck do not allow the logging operator to pull out ofthe rope socket. Cut tine and strip overshot over wire line to pult logging toolout.
Make zure logging operator keeps winch turning to minimize sticking of wirelineand tools
Rule 9:
Rule 10:
23:4
Murchisnn Ilrillino Schoof,s - In
)Xm. LOGGING RIJLBS FOR DRILLING (cont.)
Rule 10: (cont.)
atlr! d !ilrlloi !q&l Slrll&rll t&tto
atEt !€u. (aP) alrl. orPctotial m-ahrl.
e.rr l|t (Of) ahl. ornorFa!ala(Litlorott)
l.3i3tiwl'tytlorc lcn l (la') l.dtnstlt
L3i3tl,rl'ttlldEtlc (d..f)) Ipl:nctlt
cddlcttrttt(d..P) l.a{r.ctlt
lai.c (EC) llcl. .r.Gttop. ot ton
LEtroa llditactlt
Drilll.Eg Lt.( r .o . r . )
D.srltt
c-aat !o!d(cr.)
crliF!
lrdirEtlt
tldl'E €tlt
Io To
ladlnctfl hdtrctlt
Io
lo
l..
laa
taa
tldinctlt
taa
ta3
fa3
t.a
l. l
laa
tldlr.ctlt
lldlretlt
x.ll @atrcl
ladir.ctlt
IDdiretlt
r.ll @atrt
h.tia.qtlt
1.. (rrrbbg/.foughflg) (9€dtor Licl<ftt'lug.)
fl\rat st.r &o1n lolo
rlt llrld totar orc.aad hla
llai-trt.ta.ct a llt|i!v.aionlor tsrd
lctf tlsld rEcraad lola
lot tlu{d trEraaa Lala
r8t tlda rrcaaad lclo
rat thtd rOFa or u-cerd bob
lot tlEld Iotn lol.
lrt tlrld totra! Dola
br thld Icrr.d lol.
rDt thld ruscarad Lola
l.a
lctttD.
l.r
lo
l.a
Io
Io
lo
l.a
laa
laa
Io
I8.li,nctlt
Iar
lar
fo
Io
Rule 11: Density and Neutron Rules
The heavy nDensen line is the Density Curve.
The thinner line is the Neutron Curve
For porosity, read 50 to 60% between lines (halfway).
Lithology Rules-of-Thumb :
1 .
2.
3 .
4.
A. Dolomite:
B. Limestone:C. Sand:
D. Sand:E. Shale:F. Anhydrite:
The Density Line is to the right of neutron. Read 60%to left of density for porosity.The Density and Neutron bave very little separation.In clean sand you have 6% (3 spaces - each spaceequals 2%) - separation between Neutron and Density.The Nzutron Line will be to the right.The Neutron Line will be to the left.Density kicks off scale to right and back on near depthscale. Neutron = n0" porostty.
23:5
Murchisou Ihilling Schools. IncaaaaaIttta,
tItIIItDtII,
tt)
tIt,
tt,
t,
tI,
)
t)
)
,
)OilV. GAS KICKS AIID BUBBLE RISE TO SURFACE
Most blowous and many other drilling problems, zuch as lost circulation, differential stickingand liner lap leala, occur when formations containing gas are drilled. The severity of thedrilling operational problems are influenced by: thickness of the formation containing gils;permeability; the presence or lack of fracurres; and the amount of mud-overbalance increase thatdevelops when driling the hydrocarbon section.
Rule 1: Choose a conftctor that has well trained and motivated people-no matter how muchmore the day rate costs. Remember a blowout cost millions of dollars and a thirty-daydrilling program thm gas and hydrocarbons would only cost $150,000 if the dayworkrate was $5000/day higher than another rig without the best trained people. Look atpeople when making a rig selection. Remember the kick tolerance for a 3O-barrel kickwould be far less than a lGbanel kick. Crew awareness and knowledge could be thedifference between a costly underground blowout (lost circulation) and a routine kickproblem.
Now let's look at each red flag separately.
MONITOR TRENDS OF:
r Pump Pressure/Pr.rmp Strokeso DraB Up & Drag Downo Torqueo Flowline Temperatureo Total Mud the Hole ReErires on each Trip
Out and Mud Gained when Pipe is Run Inand Compare the Actual vs. TheoreticalTrend of these Numbers with Previous Trips.
Rig-up equipment to: easily detect kicks and be able to start fluid in the annulus if lostcirculation occurs. A rig's circulating and zurface system must: have goodsupervision; have excellent discipline in reference to pit measurements and volumebuilding or jetting; have sensitivity to volume changes; contain a safe working volume;and have adequate mechanical equipment to catch a loss or gain in volume.Remember, however, that mechanical pit monitoring equipment will not replace agood pit supervisor.
24zL
Rule 2:
-|
qIofiI/. G.A,S KICKS AIYD BUBBLE RISE TO SLJRFACE (cont.) I
HOW ST'RFACE AREA ATTECTS PIT VOLI.JME
For maximum pit-volume change use minimum surface area
3 in = l0 bbl of volume gain3 in = 30 bbl of volume gain with 3 pitsBut...the pit-volume totalizer movesthe same disunce
A TRIP TANK WTTH DMENSIONS OF 5.8 FTBY 5.8 FT AND t.O FT IN HEIGHT WOULD GIVE:
. TOTAL VOLUME - 48 BBL (269 CU FT)
. SENSITTVITY - 0.5 BBL/IN- 2.O IN/3BL
IITdIIIC;
!IaIatTCIa;
IaIaaIaa!a!t!!a!Jt,ala
It h
I
CAUSES OF KICKS
TO ALLOW AKICK
BY NOT FOLLOWING A PROPERFILL IJP PROCEDIJRE
CAN ONLY BE CLASSIFIEDAS
NEGLECT
Reduction of hydrostatic pressure through lossof drilling fluid o formation-lost circulation
A:2
l'.?
FFppPFppFFFrppftftppFIttfrtDDrt!)!tDrtDDrtrtI'rtrtrtDtt
*rr. "*
KI"o or- "
Rule 3: When drilling a formation containing gas expect gas-cut mud. Porosity gas, from drilledchips, will cause gas cut mud. Gas cut mud does not Decessarily require mud weightincreases because the expension of gas (and cutting of mudweight) will occtu regardlessof hydrostatic pressure. If a driller observes the well to be flowing, and shuts the wellin, and has a measurable drillpipe pressure, he should then calculate a new mud weightand make a kill plan. Many operations only reguire a change in drilling practices not acbange in mud weight. Operations that drill shallow gas may need to: reduce the rate-of-penetration; reduce the hole size; or a combination of the above.
Formulas:
PrV, = PrV,
P,V,v^=-.P ,
Pan,r = N x 2.3 xLogP,
Ap = AVx#*
N=Wo - lvIW")
Pr=-ATM
lvf\il"
DepthxlvfWox0.052
Where:
15
: Formation pressure, psi
: Initial pit gain (assumed* to be equal to originalvolume of intruding gas Oarrels).
*Note: When drilling with oil mud this assumption isnot valid because some gas is dissolved and thepit gain can be misleading.
: Hydrostatic pressure at any depth in the wellbore, psi
: Expanded volume at pressure (P), barrels. P, may beamospheric pressure 1a.7 psi (15)
: Reduction of hydrostatic pressure in atuospheres (oneATM = 15 psi)
: Ratio of gas to mud
Pr
vr
P2
v2
Pot"
NA:3
(Murchison lhilling Schmls. Inc.
,,i
)OilIr. GAS KICKS AIfD BIJBBLE RISE TO SIJRFACE (cont.)
Rule 3: (cont.)
MWo : Original mud weight, (uncut in ppg)
MW" : Gas cut mud weight at zurface, ppg
Log P, : Log of hydrostatic pressure on bottom, amospheres
Depth : True vertical depth in feet
AP : Hydrostatic pressure reduction on bottom, psi
AV : Change in pit volume in barrels
GM : Mud gradient, psilft (MW x .052)
Ann. Vol. : Volume between casing and drillpipe in barrels/ft
Example 1: A formation containiqg gas is being drilled. Calculate the reduction in bottomhole preszure. Given: TVD : 12,000 ft; 9-518" x 5" Ann. Vol. : 0.0459bbVft; Pit gain from porosity gas-cuning = 6.0 barrels; mud weight : 14ppg; gas cut VfW = 7.0 ppg. Estimated porosity g6 @ 8536 psi : 0.44 gal(or 0.01 bbl).
Pz= 12000x14x.052t <L J
= 582 ATM
Prnr = (1)(2.3XIrg 582) = 6.36 ATM
AP = 6.36 ATM x 15 psi/ATM = 96 psi reduction
AP = 6.0 bbl * t1 l,'=T'-9Yl) = e6 psr0.045e obuft)
Therefore: The bottom hole pressure reduction is approximately 96 psi. This wouldprobably be within the trip margin or hydrostatic pressure overbalance.
Examole 2: What is reduction in hydrostatic pres$ue due to gas cutting of the mud? Themud weight is cut from 18 ppg to 9.0 ppg, depth(s): 1,000 ft; 5,000 ft;10,000 ft; and 20,000 ft.
(
II(
(
III(
(
ttttttttttttttIIItIIIIttIItIttI
N_14-7_17
A:4
Murchison Drilline Serhools. IncaaaItI!taaIIIIItIl'
IIIl'
tI'
tttIItIttaIIItItItt
)OilV. GAS KICKS AIID BT BBLE RISE TO SURFACE (cont.)
Examole 2: (cont.)
Prru = (1X2.3XLog 62.q = 4.12 ATM
AP = 4.12 x 15 = 62 pst
20,000 ft. P, =
N_18-9=9
20000x.052x18
= 62.4 ATM
= l?A8 ATM
NORMAL HEAD REDUCED18 poe MUD HEAD
1,000 ft. P, =
p= 18-99
DEPTH
1,000'5,000'10,(x)0'20,000'
1000x0.052x1815
=1
936 psi4,680 psi9,360 psi18,720 psi
15
Par,, = (1X2.3XLog 1248) = 7.12
AP = 7.12 x 15 = 107 psi
HEADREDUCTION
866 psi4,598 psi9,265 psi18,615 psi
60 psi82 psi95 psi105 psi
Rule 4: In an open annulus (circulating or drilling), without backpressure being held, thegeneral gas law applies. Basicdly it states if the pressure is cut in half the volumeof gas will double (PrVr = PzV). Most of the doubling (gas expansion) takesplace near the zurface. In oil muds the gas will expand nearer the zurface. HtSgas is also more soluble and expands nearer the zurface han sweet gas.
VduE -+
v" = Prv,"P ,
Where:
Allowing gas to rise in a conuolled expansionkeeps bofiom hole oressure consant, reducespressure+ffective gradients at casing shoe,and reduces strain on surface equipment.
= expanded volume at pressure Pu (bbD= initial pit gain (assumed to be equal to
original vol. of intruding gasXbbl)= formation pressure, (psi): hydrostatic pressure at any depth in
the wellbore, (psi)
v2vr
PrP2
24:5
)OilV. GAS KICKS AI\D BIJBBLE RISE TO SIjRFACE (cont.)
Rule 4: (cont.)
Example 1: What is the approximate volume of expanded gas? Given:Formation pressure : 6050 psi; mud weight = L2 ppg; 9-5/8, 43.5lb/ft casing and 5 inch drillpipe; tnre vertical depth : 10,000 feet.
Case 1: 0.25 bbl at 5000 ft and at zurface
(6050x0.2s)vrr* o = = 0.50 bbl
(5000x12x.O52)
Rule 5:
v^ = (@--l:-''-t = 100 bbl (Approx. e:rpanded volume of gas)' 2 , , r d l J
z \ ' r r r r v ' v r s v
Case 2: 1.0 bbl at 5000 ft and at zurface
v, *=. (6o5ox1'o) =1.q4bbl,r@ r. (5000 x 12 x .052)
v^ - (6059X1'0) = 4o3 bbl (Approx. expanded volume of gas)'2d IJ
! \"rrrv^'
When a gas kick is closed in assume percolation can take place. Bottomhole preszure must be maintained constant by correct monitoring andbleeding to allow the gas bubble to expand. Percolation is fastest in salt(brine) water and slowest in oil muds.
ApunPerC- = -
IS GM
V-od = \ x Ann. Vol.
Where:Perc" -- Estimated percolation rate in feet per hour
APde : heszure increase ondrillpipe (psi per hour). The drillpipe(SIDPP) pressure is monitored for about 10 to 15 minutesand this pressure equated to one hour; i.e., 100 psiincrease in 10 minutes would be 600 psi/br.
GM = Mud gradient, psi/ft
GM
2426
Murchison llrillins Schools. Inc.,DappftpttpttpppDPpI|rtDlDprtDEDDDDDrtrttrttIr'rtrtrtrttrtDrt
Ifrw. GAS KICKS AND BUBBLE RISE TO SURFACE (cont.)
Rule 5: (cont.)
V-d : Volume of mud in barrels that must be bled to maintainconstant bottom hole pressure with a gas bubblepercolating (risine).
& : Incremental pres$ue stepG) that the casing pressure willbe allowed to increase (psi).
Ann. Vol. : Annular volume betrveen drillpipe and casing (or dp/OH)in barrels per foot.
Example 1: Wbat is the estimated rate of percolation and how would bottom holepressure be mainained constant? Given: SIDPP = 583 psi; SICP = 1150psi; TVD : 13,500 ft; Fp = t0,762 psi; pit gain : 30 bbl; length ofinflux : 854 feet; Ann. Vol. = 0.0489 bbuft (8.681" x 5n annulus);pressure increase per hour : 500 psi; lvfW = 14.5 ppg. Bit nqt plugged.
Perc*= ' -H-=663fee t /horu(14.5 x .052)
Since the bit isn't plugged bottom hole pressure can be maintained duringpercolation by maintaining constant drillpipe pressure. Choose a smallsafety factor; i.e., 50 psi over SIDPP (633 psi) and do not allow thedrillpipe pressure to go over this number. Mud will have to be bled onthe annulus choke to keep pressure at the 633 psi on the drillpipe.
Example 2: If the bit was plugged how many barrels would have to be bled to step thebubble out volumetrically so that bottom hole'preszure is maintainedconstant? How is this done? Same given infornation as Ex. 1. Preszureincrement to calculate bleed volume : 100 psi.
v .=mlxt
(100x0.048e)= 6.49 bbl(14.5 x .052)For each 100 psi increase on casing.
To maintain constant BHP using the volumetric method:
1. Choose a small safety factor; i.e., 100 psi.
2. Allow casing to rise to 1250 psi (1150 + 100 psisf).
3. When the preszure increases to 1350 psi bleed 6.5 bblwhile maintaining 1350 psi. (Max. overpressure is 200 psi.)
4. Allow the preszure to increase to 1450 psi. Maintain1450 psi while bleeding the 6.5 bbl.
5. Keep repeating this procedure until the gas bubble is atzurface (do not bleed gas without lubricating mud in at surface).
2427
Murchison Drinine Schools. Irc.
)OKIV. GAS KICKS AIID BTJBBLE RISE TO STJRIIACE (CONI.)
J- l
ai;
;
;
I4€
;
CCC;
CIC;
I;
Ja
Rule 5: (cont.)
Example 2: (cont.)
"hijE t' l
1150
Rule 6: Use the ratio tecbnique to estimate: the position of the bubble when kill weight is
at the bit (FCP); and the number of strokes to move the bubble to the casing shoe.
The greatest pressue is applied to the shoe when the bubble is in the.open hole.
The number one associated problem to well control is lost circulation. Inst
circulation is caused by exceeding the murimum allowable pressure based on a leak-
off test at the casing shoe. The calculated maximum allowable pressure applied
when the bubble is in the open hole. Keeps kicks small to avoid reaching
breakdown Pressure.
Formula(s):
Ratio = (Ann. Vol.)
@P cap)
Final circulation presstne = slow circulating pressue x kiu lvfworig. lvIW
ICP : Initial circulating pressure = SIDPP *slow circulation pressure
SIDPP : Shutin drillpipe pressure
/TD\Brop=DB-l**, l
(D- - CSJ DPCAP x RatioSTK$ =
Prbo" = F, - [Hydrostatic pres.sure of all* fluids below Soe]
Poof = F, - [tlydrostatic ltfessure of all* fluids below srrface]
CCCeCCCI!CtttttttttIa
Volume
Unplugged drillpipe
Volume
?At8
)
7tI.Ibbl'l'ADput7tI,!I'ItrtrtI'I'I'ItItI'rtr'ttItrtrtD!)brtDITDtDDI'I'
Murchison Drilline Schools. Inc.
)OKIV. GAS KICKS AwD BUBBLE RISE TO SIIIIFACE (cont.)
Rule 6: (cont.)*Possible Fluids: (1) Original Mud
(2) Influx(3) Sometimes kill weight
AP*, = (L.O.T.M* - N,fWH)0.052 x shoer,t
l P \LIWE=lvf 'Wr* l===='Y I
[0.052 x Shoer,r/
Bubble Pressure Bp = Fp x Kv/(Kv + Bv)
BubbleDepth Bd = TVD- [(Fp-Bpylvtwx0.052]
Where:Bp : Bubble Pressure, Psi
Bd : Bubble depth Om) ft
Fp : Formation pressure, Psi
Bv : Bleed volume, bbl
TVD -- Original TVD, ft
Ratio : The ratio factor (no units) between the annulus and the drillpipe
Ann. Vol. = The annular volume calculated either in dp/OH or dp/csg ObVft)
DP CAP : Drillpipe capacitY ObVft)
Bro, : Estimated bubble top after circulating capaclty of drill string(kill weight at bit or at FCP, ft
DB : The depth of the top of bubble before circulation begins, (FT)
(uzually TD - length of influx)
TD = Total measured depth
sTKh : The strokes to move the influx bubble to,the shoe
CSo : Casing shoe measured dePth, ft
A:9
Murchison Ihilline Schools. Inc.
)OilV. GAS KICKS AIID BLTBBLE RISE TO SURFACE (cont.)
Rule 6: (cont.)
I,1
7
111tl+14A1IIC444JJaJJJJaattIrlItt|l|ltt
P.O. =
P.* =
Prort
FP
woo,,
Shoe*o
Hydrostatic Preszureof all fluids : Each fluid is calcutated individually
tHP - kn fluid x lvfW(ppg) x .052I
MWE = Mud weight equivalent at casing shoe, calculated fromshut in casing pressure and the mud weight in the hole(shoe to zurface), ppg
AP-, = Maximum allowable zurface pressure on casing when theinflux bubble is in the open hole. It is based on aleakoff test below the shoe.
L.O.T.n*r = The equivalent mud weight calculated from an appliedpressure on the surface to the point the formationtook fluid (leaked-off).
Pump Output (banels per sEoke)
Pressure being applied to casing shoe with a kick inthe hole, psi
Casing prcssure at surface with a kick in the hole, psi
Formation pressure, psi
Mud weight in the hole, ppg
The tnre vertical depth of the casing shoe where leak-offtest was nrn.
Calculate ratio. Estimate the strokes to move the bubble to the shoeand calculate the estimated position of the bubble when the killweight is circulated to the bit (FCP). Calculate mardmum allowablepressure and the equivalent mud weigbt applied to the shoe wheninitially shut-in and after circulating the bubble to the shoe. Given:Depth (MD and TVD) = 13,500 ft; SIDPP = 583 psi; SICP : 1150psi; Fp = 10,762 psi; mud weight : 14.5 ppg; length of influx =854 ft; Influx = 30 bbl; Dp = 13,500 - 854 = L2,646 ft; annularvolume = 0.M59 bbl/ft; drillpipe capaclty : 0.0170 bbl/ft; p,'mpoutput : 0.095 bbUstk; leakoff test mud weight : L7.7 ppg @10,000 feet (casing shoe MD and TVD) shoe; kill weight = 15.33PPg; Mg = 0.7540; Fg : 0.7972.
Example:
242L0
Mnrrlrisnn Drillino Schrnk^ f ncaaaIaaaa)
tttattttttDtttttttttttt)
)
)
t)
)
t)
)
)
)
IOilV. GAS KICKS AlrlD BUBBLE RISE TO SURFACE (cont.)
Rule 6: (cont.)
Ratio=ffi =2.7
STK* = (12,&6 -10,000) 0.0170 x 2.7 = 1278 strokes
To move bubble to casing shoe0.095 bbvsTK
Brop = 12,646 - fryl = 1646 ft.\2 .7 )
Therefore the bubble would be up in casingbefore kill weight leaves the drill string.
AP,,, = (L7.7 - 14.5)0.052x 10,000ft: 1664psi
lvfwE = Gnitially) = 145.aoffi = 16.7r WgThe equivalent mud weightapplied to the shoe when thewell is closed in initidly.'
v. (at shoe) - (10'762 psiX3O) = 42.82 bbl' - (14.5 x .O52 x 10,000 ft)
L htshoe) - 42'82 bbl = 933 ft'I - 0.0459 bbvft
Psho" = 10,762 - t(933 x 0.1) + (3,500 - 933) 14.5 x 0.0521: 8733 psi
lvfW" =
orPru.r ==
MW, =
Note:
9733 psi = 16.79 ppg0.052 x 10,000
t0,762 - (933 x 0.1) + (13,500 - 933)14.5 x .052I1193 psi
r4.5 +f 11e3 \\0.052 "'
lqoooj = r6'7e ws
There was only a slight increase in preszure applied toshoe comparing initial condition with bubble @ shoe.
Z.zll
Murchison Dri[ins Schools. Inc.
.a
F
IXw. cAS KICKS AI\[D BITBBLE RISE TO SURFACE (cont.)
Rule 7: The estimated maximum surface casing pressure, with the bubble expanded atzurface, should be calculated before implementing kill plan. There are caseswhere burst is the limiting factor, particularly if casing wear has taken place dueto long rotating hours.
Formulas:
Method 1 (Ouick Estimate)
?FFFFFFaFaaaaa]saFrtaaFa)f)aaeFOF-
1=
t-
E-
-
-
EFeee
P".r..r* = '* (PxVx lv fW* r
v. _ofp*v*c)ot'ga|n DaL l l\d\ilK )
Method 2 (More Accurate)
v*"-o. = GJmlI
Where:
^ f(ffi)c',-',r-qxo'r)l^-L 2 j
: Approximate maximun casing pressure resulting from circulatinga kick out using the wait and weight (constant bottom-holepressure) method, psi.
P : Formation pressure in thousands of psi (F, x 10r).
V : Pit gain (volume of gas at bottom of hole), barrels.
MWk : Mud weight required to balance formation pressure (kill wt), ppg
C : Annular capacity at surface (DP/csg annulus) in barrels per1000 feet.
(Fr)N(-0.194) + (4.16)
P."r,o"*
Por.."*.
24:L2
-
-
-
.t-
t)tt.)
-
tta-
a-
ttaaaa!)aa!tIttatta)
ttt)
tttI)
)
,
: Annular capacity at surface @p/csg annulus) in barrels per foot.= Mud gradient original mud psi/ft.
: kngth of influx when well is initially closed in. (calcurated frompit gain and annular volume around drill collars or ariu collarsand drillpipe.)
%* "* : yffiffi *l"fiil t:,n:*ffi##lH,x:j'i:$, oH1,Example: Use the given data under Rule 6 example. Calculate the maximum casingpressure and maximum volume gain when circulating the gas bubble to. zurface. Compare Method I to Mettrod 2.
Method 1:
(cont.)
Where: (cont.)
Fp : Formation pressure, psi (hydrostatic pressure + slDpp)
Fs = Formation pressure gradient, psi/ft (formation pressure/TVD)
LN = Natural log
DS Vol. - Drill string total volume, barrels.
Ann. Vol.
P".r.."* = 200 t0 .762x30x15.3
t'(t
l"
= 2012 psi
D _ ^ (10.762 x 30 x 4g.9^ g a r a m a r - - l -
\ 15.33= 128 bbl
rMethod 2:
^ - [ffi e'7s72-o'7s4)-(Bs4ro.rl-=
[ 1= s6'2+
Po,."*]:.r:f f:-'t4)2+t(to,"r(#)<o.tstz,t(10,762)tN(-0.3e4)+(4.16)r": 1683 psi
A:13
Murchison Drillinq Selools. Inc-
)Oil\r. GAS KICKS AND BITBBLE RISE TO SURFACE (cont.)
Method 2: (cont.)
Vg"io.r* _ (10,762)(30X(10,762)tN( -0.394) +(4. 15)I1683
= 96.3 barrels
Note: Method I calculated a higher casing pressure and more expanded gasvolume than Method 2. Therefore, Method 1 would be considered moreconservative (if casing and wellhead is safe with higher pressure theoperation should be safe).
Rule 8: A lubricating techniEte can be used to lower zurface pressure if gas is at zurface.An example might be no plpe in hole or a ptugged bit but gas at zurface. Alubricating schedule is calculated and mud is pumped in below the ram(s) whilepressure is reduced by bteeding gas off. This is done so that another operation,such as stripping, can be performed. The breakover from snubbing to strippingnrle is that it reErires approximately I foot of drillpipe for each psi of surfacepressue; however, 1 stand (90 ft) of drill collars will counterbalanceapproximately 250 psi (0.35 fl/psi). If gas is at zurface lubricating can be doneto reduce zurface pressure and consequently avoid having to snub.
Formulas:
Fa"=Lo"xDCo l
Ad" = @CODF 0.7854
-sF
h=lvfwl x .052
P,=F*"A*
!CtttttIaCTT;
CCCTCCCTCttt!tttt!tr!tt:
I!tt!ttItrt,
csg
P - P - )rr - 1^ csg
I,IID h
Incremental Vol. =
Where:Fd"
Lo"
Incteme,ntal Press.
h
The force created by one stand of drill collars, lb.
Ir4gth of one stand of drill collars, ft.?A:L4
,
-Murchison lhilline Schools. Int
- EKn/. cAs KrcKs A|ID BT BBLE RrsE To suRFAcE (cont.)-
- Rule 8: (cont')
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-,
t)a-
tl-,
t,-
-
DC* = Drill collar weight, lb/ft.
A" : Drill collar area based on drill collar outside diameter.Note: A float (backpreszure) valve would have to be used;conseErently, the total area is considered, in sq. in.
DCOD = Drill collar outside diameter, in inches.
PL : The safe pressure to begin stripping operation with, psi.
SF = Safety factor below balancing pressure, psi.
[c : hbricating factor, pressure per barrel of mud (psVbbl).
MWL = hbricating mud weight (ppg). The best lubricating mudis a low gel strenglh salt sanrrated mud. The worstmud to lubricate with is an oil mud.
Vac = Volume of casing, bbvft.
V,uo : The total lubricating volume to reduce the surfacepressure to the desired stripping prcssure, barels.
P.., = Initial pressure on casing, psi (before lubrication).
Incremental Vol. : Incremental volume for pressure increment, barrels.
Incremental Press. : lncremental pressure, psi (chosen for convenience -
usually 50 to 100 psi).
Example: Make a lubricating schedule. Given: pressure on casing = 500psi (gas at zurface); mud weight to lubricate with 17 ppg; casing= 7",35 lb/ft; volume : 0.035 Obl/ft); drill collars = 4-314" x2" x 50 lb/ft x 90 fl/std; SF reErired = 100 psi; incrementalpressure : 100 psi. Make stripping schedule. No pipe in hole(Gas Preszure below Blind Rams).
Fo. : 90 ft x 50 lb/ft = 4500 lbs
A" : (4.75)2 0.7854 = 17.72 sq. rn
D 4'500 lbE1 : - - 100 psi = 254 psi-100 Psi = 15a psi
" 17.72 qitGevl5!-p$)
24ztS
Mwchison Drtlline Schmls. Inc.
)trIV. GAS KICKS AND BUBBLE RISE TO SURFACE (cont.)
, _ (17 x .09_z)psj/t = 25.26 psi/bblT - (oor:)bu/n
(weight of gas ignced because SF is being used)
17 (500 - 150)psvft _ r.Vh,b=ff i=13.86bbl
Total volume to lnbnicate pressue down to f50 psi.
Incre,mental Vol = ==t9 *,t': = 3.96 bbVlO0 psi25.26 psflft
Volume @bl) Pressure (Casing)
0 500 psi
3.96 400 psi
7.92 300 psi
11.88 200 psi
13.9 150 psi
lnhial Cordition
Gas is very compressible at zurface. Pump in sas
each increment of mud slowly and surface prcssureshouldn't change much. Give time for gas tou-nrbe or break tbrough the mud. Bleed gas offand lower prcssure in incremental amounts untildesired pressure is reached. Use an exact tank to measure the mud increments.After lubricating pressure down to desired level strip in drilpipe. After a fewstands a constant bottom pressure circulatiag method can be used to clean upsurface and this will make it easier to measure stripping volume Gtripping volume= DP capacity + DP metal displacement).
i.e., 3-112",13.3 lb/ft, IF, 'En, Adjust DP : l4lblftcapacrty : 0.007386 bbl/ftmetal disp = 1412748: 0.0051 bbufttotal : 0.0125 bbUfttotal for 94 fl/std = 1.17 bbl
?:f E@.,l L, *** nL_i
IIIIIIItttttttItttttttItIIttIIIIIItII
I
!
I
I
I
I
Final Condition
Snppng Schedule
Stands (DP) Casing Press Volume
0I23
etc
150150150150CIc
0l . l7t . t7t . t7Etc
?A:L6
Murchison Drillins Schools. Inc
I\dW")
lvfW*)
(2r.66
aaaaaaaaaaaaaaaaaatItaaarlaaaaaaatataaaaa,
a,
,
IO(V: MtiD VOLUME BUILDING FORMULA(S)
A pencil should be put to materid and volume requirements before the volume building processstarts. This will ascertain that volume requiremenfs are met and the materials are on hand.
Rule 1: To build volume from water to some final mud weight, the following procedureshould be implemented: lst calculate the starting clay base mud (V); 2nd calculatethe sarting water volume (V*); 3rd calcrrlate the required clay (clay req., pounds);4th calculate the required barite (barite req., pounds); and 5th calculate the materialbalance (volume check). The formulas are based on high densrty solids having aspecific gravity of 4.2 and the low density solids having a specific gravity of 2.6. ThereErired known information is: final mud weight (MWp); mud weight of water-claymix (base mud) (MT[); and the final reErired volume of mud (V").
Formulas:
[(rs _ ]fwF)lV =V- l 'vc-" [€s-IvrqL) l
u*=u"I' I et.aa
ClayReq.
BariteReq. = Y"
_ \7 [910(MW" - IvfW*)l
" [ (2166 - Ivrw.) I
Vol. Check
Where:%
vF
_ v * (Clay Req.) . (garite neq.)w \e lo / \1470)
MwF
MW"
v*
Volume of clay base mud, barrels.
Final volu-r required, barrels.
Final mud weight, ppg.
Clay base mud weight, ppg.
Volume of starting water, barrels.
IVeight of water, ppg.MW* :
25zL
-
Mmchison lhitting Schools. Inc. I
Clay Req.
I
a
I
aaaaaaaaaaaaaaaaaaat
J
al
aJ
J
J
aaaaaaaaaaa-
(3s - 13.s)= 814 barrels of clay-based mud.(35 - 8.O
E(V: MUD VOLIIMB BIILDING FIORMIJLA(SI (cont.)
Rule 1: (cont.)
v" = looo
Clay Req. =fPg
(13.5 ppe)Final Vol. d finishcd mrd
= Clay required to build weight (and viscosity)to desired level, (lbs.)
Barite Req. : Barite required to reach final mud weight, (lbs).
Vol. Check = Volume check to assure material balance (also checksarithmetic because if the number isn't close to V,a mis123s was made), barrels.
Example: Calculate the material and volume requirements. Given: desiredmud weight : 13.5 ppg; final volume reErired = 1000 barrels;estimated claybase mud weight based on experience = g.6 ppg;weight of starting water = 8.33 ppg.
V* = g1a -2q : 8'q = 798 bbl of starting water.
910(8.6 - 8.33)
ffi=15'ol2 lbs
of clay (or bentonite)
Badte Req. = ar+ t4?,1!13_'sr'.ai'6) = 272,7@ Lbsof barite required to raiseweigbt from 8.6 to 13.5 ppg.
Vol. Check = 798 + 15912 - 272,709 = 1.000 bbl910 LATO
\=v,tffi]092 (MWF - lvfW
I t 'o- |w(8'6 ss1
Vol. OayBe Mrd
I rsr* |;-F._l
E.': \Afl'.':.!
€3pe1Vol. d Staning W.tet
ffil'ryy)
Rule 2: Add water with barite to maintain good mud properties (Av, pv, yp and gels),if raising the mud weight of a fietd mud laden with drill solids.
2522
Req. Barite = V,Q6 - tvfwF)
.o-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
a-
a-
-
a-
a4-
-
-
-
-
-
-
t,t-
ta,)
-
ADJIJD
D
Murchison DriUine Scbools. Inr
IOil/: MIJD VOLIJME BIILDING FORMULA($ (cont.)
Rule 2: (cont.)
IVhere:
Example: A kick was taken at 13,000 feet requiring mud weight to be raised from 13.5ppg to 15 ppg. The solids are on the high side. Water is needed with bariteto keep mud properties in reasonable shape. Calculate the starting volume,barite, and water to build 15 ppg volumes, final volume is required to be1000 barrels.
v*. = v" = [**'.,F* * v-lr+v" | - l47Ol
r, _ Req. Baritenr=ff+Vqo*Vs
V, : Starting volume before barite and water are started, barrels.
Vrrro : Volume water, barrels.
VF : Final volume, barrels.
LIWF = Pinal mud weight, ppg.
Iv[Wr : Initial MW, ppg.
V, = 1000 l9#.:l = SgO UUt start with this volume ro end up withl,<za - l3-5)J required final volume (1000 bbi).
Req. Barite = 880 ftogz-(ts :-tg'sl = nr.ooo tt. Mix this much bariteL (ro - rr) J (along with water).
vrlo = 1000 - [f titt#) .880] = 30.86 bbl Addthiswaterwithbarite..2"
L\ r47O ) J
V" = f t?!ry) + (30.80 + (880) = 1000 bbl Finalvolumeof l5ppgmrd
" \ l47O ) ---- '
required.
Rule 3: The general procedure for mixing and pilot testing oil muds is listed in steps on Page25:4. The formulas and calculator progams for oil (and water base) muds can bepurchased, as part of Rig File Progran for HP48, Qater will have on PC) fromMurchison Drilling Schools, P.O. Box 14577, AlbuErerque, New Mexico 87L91.
25:3
Murrhison Drillins Schools. Inc.
)OtV: MUD VOLUME BUILDING FORMULA($ (cont.)
Rule 3: (cont.)
OIL MDtrNG PROCEDIJREGENEML)
Step 1 Put oil in clean mixing t^nk.
Step 2 Add emulsifier, wetting agents and mix thoroughly.
Step 3 Add lime - mix well.
Step 4 Mix brine wat€r (CaCl, or NaCl) in separate tank. Mix well.
Step 5 Blend brine water with oil mix and agitate thoroughly.
Step 6 Add necessary chemicals to give tight emulsion (stability test).
Step 7 Add weight material and mix thoroughly.
PILOT TEST GTJIDES
VISCOSITY
A. Insufficient1. Improper OiVWater Ratio
a. Add waterb. Add necessary chemicals
2. New Mud-Normal Thinninga. Add lime and necessary chemicalsb. Add necessary chemicals
3. Water West Solidsa. Add necessary chemicalsb. Decrease salt content
1) Adjust water fraction above sahuation point of salt2) Add new mud
4. Rapid Salt Increasea. Adjust water fraclion above saturation point of saltb. Necessary chemicalsc. VG-69 and/or basic package if additional viscosity is needed
5. Chemical Undertreamenta. Add basic packageb. Add necessary chemicals
6. Gas Strippinga. Increase density of fluidb. Add barit€ with necessary chemicals
F!!!!!!!!!!F;
!aaat!!tat!rtt!It,
It!!!!!!!!!IIIJ
2524
u-
-
-
-
-
-
-
-
-
-
-
.D
.D'Dtt-)
.Da-
-
.t
.)
aD.)
aaf)
J)
aaaaaaaaaattaa
Murchison Drillins Schools. Inc
)Oil: MUD VOLIJME BIJILDING FORMULA($ (cont.)
VISCOSITY (cont.)
B. Excessive Viscosity1. Fine and/or Excessive Volume of Solids
a. Displacement with new mudb. Dilution
2. Water-Wet Solidsa. Add necessary chemicalsb. Disptace with some new mud
3. Improper Oil to Water Ratio @xcessive Water)a. Diqplace with some new mudb. Treat with necessary chemicals
4. Acid Gas (Cq and Hrs)a. Add lime (Mp greater rhan 5.0 cc of 0.1 N H2SO4)
5. High Boftom Hole Temperaturea. Displacement with some new mudb. Add lime and necessary chemicals
EMIII^SION STABILITY
A. Decreased Electrical Stabiliry1. Decreased OilAMater Ratio (Volume Water Gain)
a. Diqplacement with some new mudb. Chemical treament as necessary
2. Insufficient Treahenba. Add necessary chemicalsb. Add lime
3. Salt Increasea. Add some waterb. Treat with necessary chemicals
4. Periods of Mud Inactivity
B. Increased Electrical Stability1. Increased Oil/Water Ratio (Volume Water Fraction Decrease)
a. Addition of diesel or crude intrusion1) Add necessary chemicals2) Add necessary chemicals
b. Evaporation of water1) Add water2) Add necessary chemicals
2. Normal Stabilization of Oil Mudsa. Improved stabilization of oil mudsb. Chemical treament
25:5
Murciison Ihitlins Schools. Inc.
)Oil/: MUD VOLIIME BUILDING FIIRMIJLA($ (cont.)
HIGH PRESSIJRE IIIGH TEMPERATIJRE FILTRATION
Excessive Oil1. Improper OilAilater Ratio (Water Fraction Too Inw)
a. Add waterb. Treat with necessary chemicals
2. Insufficient Chemical Treatmenta. Add necessary chemicals and limeb. Add necessary chemicals
3. New Muda. Shear and heat through the hole will decrease filtrationb. Chemical treament with necessary chemicals and lime
Water in Filtrate @oor Emulsion)1. Insuff,rcient Shear During Make-up
a. Add limeb. Add necessary chemicalsc. Add basic chemicals if necessary
A.
I
ttt-
ltt
f
J
J
J
-
B.
-
J-
J-
aaaaa€
to€
tttttttetttteIt!rItIt!a
2526
-
-
- )o(vT. ESTIMATING PRoDUcTIoN RATE tnPD)-
^ Rule: Use a five gallon bucket and measure the seconds reguired to fill the bucket with welltt '
fluid. Divide the seconds into 10,285 to get production rate in barrels per day.-
Murchison Ihilline Schools. Ifi
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
ta
BpD=ry=ro3bbVday100
Formula:
BPD = 10285(Seconds to fill 5 gal.buckeQ
Where: BPD : Barrels per day
Example: Cdculate the production rate in BPD. The time to fill the 5-gallon bucketwas 100 seconds.
26:t
laa Murchison llrilline Schools. Inc
la )oflflr. ESTTMATING GAS WELL FLOW RATES (MCFp)
? Rde: The approximate flow rate of a gas well through a blowdownline choke can be estimateda by muir.lplyng24 hours/day times the nrbing pressure plus 15 times the square of thel, choke size in inches.
rlJa
Formula:
1a Q=24x(Pr,*15)x(DJ2laf,
Where:
la a :Flowrate,MCFD
a PL : Pressttre upstream of choke, psi
a.
D.h = Choke size, inches
a Example: Calculate the estimated flowrate of this gas well.
a Given: tubing pressure 3500 psi; choke size : 1/4 inch.
t n ^ r - - / a , : r r t \ | r ! \ - - 11 t r \ 7
I Q=24 x(3500 + 15) x (L l4)z
l = 5,273MCFD
tIataIatItaIaaaaaItaaa 27zlaa
-
-
- I0ilfltr: ESTIMATED HORSEPTOWER REOUIRED TO COMPRESS GAS
2 Rde: The estimated horsepower to compress nanral gas can be calcularcd by multiplyng 22a times the volume of gas (MMCF) times the ratio of discharge pr"i*r. to suction1)
-
a-
L
-
-
-
-
-
J.
-
]aJ.
]a-
-
la]aIa]atataaaaataaaaatt,
pressure.
Forrrula:
HP = (22 xvohrme of gas MMCD . t
Where:HP : Horsepower
Volume of Gas : MMCF
PD : Discharge pressure, psi
R : Suction preszure, psi
Example: Calculate es "nated horsepower to compress 4 MMCF of natural gas. Given:zuction pressure 300 psi; discharge pressure : 1400 psi.
HP = Q2 x.)f#l = 411' ' \300r
28zt I
u-
- )o(x. TIrE TEMPERATURE pROp ACROSS A pRESSt RE REGULATOR
CAN BE ESTIMATEI)-
- Rule: Calculate the temperanue drop for each 15 psi pressure drop (1 ATM) across a pressure
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
regulator by multiplying the amospheres pressure drop times lolATM.
Formula:
T . = @o-P" )Pu ix I " /ATMr&oP
rs psVena ^ r 'n'
Where:Td,oe = The temperahrre &op, degrees
Ph : Gas pressure before the regulator, psi
PL : Gas pressure after the regulator, psi
ATM _ 1 ATM is equivalent to 14.7(15)/psi
Example:Calculate temperature drop if the gas pressure is reduced from 1000 psi to 500psi across a regulator
r, _ (1000 - 500)ATM _t&op= 15
x1" /ATM
= 33 ATM x lolATM
= 33o temperanue drop
29:l
-
-
-
-
-
-
-
-
'D-
-
-
-
,
r-
-
-
-
-
-
-
-
ta-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Since the wel bas more temperanue than the air above ground, an elongation would always take
place.
Rule: By knowing the temperatr[e at the time the plpe was tallied and also knowing the average
rcmperange of the well the elongation rao be estirnated. Pipe wilt elongate about 0'83
inch per 100 feet of length p"r iOO decree increase in temperature. Note: elongation
Gtretch) is also caused by hanglag weight of pipe'
Formula(s):
BHT = ( 1"F. * d"Pth) + lvfYr oF(1oo ft )
T"= BIIT + lvfYT
AT = T" - TallY TemP.
Ah = 12 ultftx o.ooooo69 ry5 t L x AT"F
AI*= L. r , lJ=x0.83--r 1oo ft loo'F
Where:BHT = Bottom hole temPerature, oF
Depth = True vertical dePth, ft
MYT : Means yearly temperahrre, oF
T" = Average temPerahrre, oF
AT : Change in average temperature, oF
At{ : Elongation in, inches
L = Irngth of PiPe, feet
30:1
t{mhion Drillino Snhrnl<- fnc^
)OG.A. ELONGATION DUE TO TEIVIPERATITRE (cont.)
Example: Calculate the estimated elongation of this string of tubing. Given: tally: 12,000 feet, measured at 4fF; MYT = 65oF, use 1oF/100 ft toestimate BHT.
I
IJ
J
t,-
tt-
f
f
-
tf
)
-
f
I/
/
(
fJfJa?aaOOt1,
trt!IEEEI!!
!
1)
Blrr = f , l=t= ltt 2,wft) + (65"F) = 185'F\ 100 ft/-
T_185+65=125"F'^-T'
AT=L25 'F-4OoF=85oF
Ah = 12 x 0.0000069 x 12,000 x 85oF
: 84.5 inches (7 ft)
or
AI -= 12 '000x 85 'F x0.83' 100 ft 100"F
= 84.6 inches (7 ft)
Difference in leneth due to thermal elongation.
30:2
Murchison Dritline Schools. Inr2-
-
-
at,t)t)-
ttt)t,t)t)t)ttt)a;
;
sa4-
aqaQ
aaaADa)ADa)JD,
aQaADf,
-
)O(X.B. ELONGATION DTIE TO STRETCII AI{D TIIE PISTON BUOYANCY-)
The weight of prpe creates a tensile force and a resulting hrbular stretch. The modulus ofelasticity is a term used to describe the stiffness or stretchiness of a zubstance. A rubber hoseacts differently then a steel urbe of the same diameter because it has a different modulus ofelasticity. Steel's modulus of elasticity is 30,000,000 tb/sq.in. The grade of the pipe does noteffect the stretch. For a given prpe size (same cross sectional area) and with the same force(or weight) applied, J-55 and P-110 will have the same amount of elastic stretch as long as theelastic limit of the weaker prpe has not beeD exceeded.
II
ss- lI
-- P-ilo
J-55
^ts'Ji"%;I'?*
Rule 1: When calculating length change, due to stretch, use air weight and calculate eachweight-section (different cross sectional area) separat€ly. Use average weight of eachsection. Note: Buoyancy is handled as a piston effect (and negates some of stretcheffect) and does not effect the stretch caused by pipe weight. Temperature stretchand piston effects should be considered separately and accumulative. A rough rulefor strerch is 0.75 ft per 1000 ft of prpe.
Formula(s):
W""g* =
StresslKbs/Sq inl
W,* * W*o*
2
AL- = L x'w""'' ErA
*Note: For each weight section of prpe starting at bottom.
4*=(Poor -PDt0 .7854
Total L, = ALr, * AL+ + ALn, etc.
Where:
AL'
wo,
E
Qhange in length due to stretch, ft.
Average
Modulus of elasticity, constant 30 x 1ff, lb/sq.in.
30:3
_l
(cont.)
A"
W"p
Poo
PD
Toal I
AL, =
W*or :
Cross-sectional area of each pipe section, sq.in.
Th_e air weig[t (acc'mulated) at the top of each pipe section, rb.Note: start ar bottom and calculate tie ait *.igf,ioi*.nsection.
The air weight (accumulated) of each section of prpe, lb. (startat bonom of string and calculate each sectioo, -oui"g io topl.
Pipe outside diamefgs, in. (tube)
Pipe inside diameter, in. (tube)
The accumulated length cbange due to stretch, ft [when there ismore than one prpe weight (x-sect area) being consideredl.
Stretch, Section 1 (bottom), ft
IIIttttttttttttet;
taFItItItIFItIt!!!!!rrrI!IrI
ra
ALo = Strerch, Section, erc. ft
Example: calculate elongation, due to stretch, for the fo[owing casing string.
Given: 12,000 ft of 9_5/g casing:Section I (bottom), 3000 ft, 9-5lg, 53.5, lb/ft, ID : g.535Section 2 (middle), 7000 ft, 9_5/9, 43.S,lb/ft; ID = g.755Section 3 (top), 2000 ft, g_S/g, 47.0:lbm.,ID = g.6gl
Section I (Bottom):
W* Joint = 3000 x 53_ll2 = 160,500
160,500 + 0 (bott.)
ALu = Stretch, Section 2, ft
W=avg = 80250 lb
4 : Q.6252 - 8.53f) 0.7854: 15.55 sq. in.
AqA x 80250)
30:4
Arr =30,000,000 x 15.55
= O.52 ft
Mrrrchicnn Drillino Snhnalc- f n,-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
a44a1a-
-
-
asaat-
af,
t)'D
_ (7000 x 312,750) = s Rl fr30,000,0(n x 12.56
ru7mft43.s eer
III
TI
3@ft Iss.s pef
It
W*Ioint = (2,000 x 47) + 465,000 = 559,000 lb
w"", = 559'ooo + 465'ooo = 512,ooo lb2
4 = (9.6252 - 8.6E121 O.teS+ = 13.57 sq.in.
AL. = -(2ooo x 512'ooo) = 2.51 ft.B 30,000,000 x 13.57
Summary:
Total I+ = 0.52 + 5.81 + 2.51 = 8.8 ft
Therefore: The total elongation due to stretch is about 8.8 ft.
)OCX.B. ELONGATION DTJE TO STRETCII AIID THE PISTON GUOYANCY-)(cont.)
Section 2 (Middle):
V/*Joint = (7,000 x 43.5) + 160,500 = 465,000 lb
w-..- = 465'ooo 1 16o,5oo = 32l,7so lb" lvg 2
J-" tJv Lv
,W
4 = p.6252 - 8.7552'1 O.leS+ = 12.56 sq. in.
Ir r . I*'l_IIIII
ALo
Section 3 (Top):
Rule 2: The piston effect is caused by pressure, either hydrostatic or applied (with pump).This pressure (outside and inside) acts on the particular area and causes a force (upor down). The differences in these forces either €use a string to shorten (most ofthe time) or lengthen depending on which force (inside vs. outside) is the greatest.A conservative estimate of length change (a little more than actually occurs) can bemade with the following formulas.
30:5
Murchison Ihitline Schools. Inc. F-t!
!EFFTF!FFFFFFFsFFFOFFtFFFF,
tllI!!IITIIIIT;
N(x.B. ELONGATION DTJE TO STRETCII AI'[D THE PISTON GUOYANCN(cont.)
Formula(s):
AL- = LxForce
" E*4
Force = Fo-Fr
F, = (nside Area)(Hydrostatic or Total Preszure), lb.
Fo : (Outside Area)(Hydrostatic or Total Preszure), lb
E : Modulus of elasticity (30,000,000 lb/sq. in.)
,\ : Cross sectional area calculated in section with smallestcross-section (lowest weight plpe), sq. in.
Area : @ipe ID or OD)2 0.7854, sq. in.
F. : Pressure outside x area, lb
Fr = Pressure inside x area, lb
,\ : (Casing OD2 - Casing IDP) 0.7854
Inside Area : Taken near bottom; i.e., casing ID bonom joinJ
Outside Area : Taken near bottom; i.e., casing shoe OD bottom joint
Example: Calculate ths sfosrtening of string due to the piston effect. Given:12,000 ft of 9-5l8u casing as follows:
Section 1 Oottom), 3000 ft, 9-518, 53.5, lb/ft, ID : 8.535Section 2 (middle), 7000 ft, 9-518, 43.5,Ib/ft, ID = 8.755Section 3 (top), 2000 ft, 9-518, 47 .o,Ibift, ID : 8.681
Mud : L2.5 ppg (Inside and outside of casing)
Hydrostatic Press = L2.5 x .052 x 12000 = 7,8@
Area Inside
F l
= (8.535)2 0.7854 : 57.21sq. in.
: 57.21x 7800 : 446.265lb
30:6
-
-
- )O(X.B. ELONGATION Dt E TO STRETCH AI\D TTIE PISTON fBUOYAr.iCn
- (cont')
- Example: (cont.)-
- Area Outside = (9.625)2 0.7854 :72.16 sq in.
- F" t = 72.76x Tgoo : 567,528 rb-
- Forcef =562,528-M,265:121,263
t aI. r2.0ffi x 12r.263-
- = 30,000,0@ x (9.6252 - 8.5352) 0.7854
-
- = 3.12ft . I
- Summarizing: The change in length for this 9-518" casing string (12,000')- examples in Chapter )OO(.
-
- Hffi** = l:8i-ff#ii- Piston : 3.9t (Shorter)-
- Net Change in lrneth : L2.7 [ Innger
- Or approximately 1 ft per thousand feet when- all three changes are taken into consideration.
-
- Rure 3: m##'"lfiili.i:tr ",frTiililTf,:;T:;';'.f;,H'.':'and the set)
-
-
-)
-,
-
-
-)
-
)
-
-
s-
-
-
.D
Murchison Ihilline Sc[ools,In!
Examples: Using the same casing string discussed in Chapters )OO((12,000 ft of 9-518"). The drillpipe is 11,500 ft, 5", 19.5 lb/ft, )GI,'S', Approx. weight of DP is22.5lb/ft (DC = 500 ft,9-112" x 3" x216lblft = 108,000 lb).
Air weight : (11,500 x22.5) + 108,000= 258,750 + 108,000= 366,750
The hole was drilled to 12,000 ft (stretch not considered). The 11,500ft of drillpipe was tallied on the surface as the hole was being drilled.The set down weight on the bit was 30,000 lbs when the hole wasTD'd. How deep is the hole when stretch is considered?
30:7
Murchison lhilline Scbools. Inc. !
LxW-A L - : - - w g
" E*4
L x Force' E*4
DP Strerch:
!t!!t!Tt!!!F!!!;
FtFrtartoIttItItItIr!I!IIrII!Irtt
ALr30,000,000 lb/sq.in x 5.2746 sq.in.
: 17.25 ft I (longer due to plpe weight)
DP Set Down Wt:
ALs11,500 x 30,000
30,000,000 x 5.2746
:2.18 ft I shorter
Therefore: The tnre depth of hole is (12,000 ft. + L7.25) - '
2.18 : 12,015 feet
From the previous problem the 12,000 ft of casingstetched 8.8 ft (12,008.80 ft). The casing wouldbottom out about 7 feet deeper than expected. Pistonand temperabre on both string would probably beclose to a wash and therefore onlv stretch wasconsidered.
11,500 ft x 366,750 + 108,000
30:8
2a.lataaaeaaa,.Daaa)1DaaaIaaa1)
)
)
aea)
)
t)
)
!)
)
)
t)
)
)
I
IOfr.C. IEMPERATT]RE COI\TVERSION
Temperanues can be corrected from Fahrenheit fD to Celsius (C) or from oC 1e op using thefollowing rules.
Rule 1: If converting to Celsius ("C) from Fahrenheit (T), add 40 to oF number and divideby 1.8. Subtract 40 from the rezult of dividing by 1.g.
Formula:
oF to .C = fJ€mP 'F + 40\
rff)-&
Example: Convert 100"F to Celsius (C).
oc =(#) -40 =38oc
Rule 2: If converting to Fahrenheit ("F) from Celsius (oC), and 40 to Celsius (oC) number andmultiply by 1.8. Subtract 40 from the result of multiplying by l.g.
Formula:
oC to op = (femp. oC + 40) l.g _ 40
Example: Convert 10C to "F.
"F2 (lo + 40) l.g - 40 = 50oF
I
FAHRENHEIT DEGREES
CENNGMDEDEGREES
30:9
A schedule of depreciation can be developed by calc,lating the percent of total depreciation forany one year.
Formula:
%Dn =2ool=1[n(1 + a1J
Where: %Dn. = percentage depreciation for the year
n : Total estimated life, years
E" : Equipment age, years
Example: wbat percentage depreciation can be taken the lst and 5th year of a piece ofequipment tbat has an estimated life of ten years.
%Dn.,=2ootffif = re.o'
%Dn,=2ootffil=uz
ttt|!t|!ttFFtFIT!sFFFt,FFtFFF:
;
:
r!I!III!r!r!J
30:10
)
tat)t)-
'Dt)t)t,tt'Dtaa,'Dtat)-
JaJ'
t)f)
ttrlD,,
tttttIttIt)
t,
)
t)
t
)OOil. APPEI\DX ACROSS REFERENCE
A
Abnormal Pnessure, Iost CirculationAccumulatorsAccumulated WeightActivity, OsmosisAdjusted WeigbtAir WeightAngle DriftAngle of ReposeAnnular VelocityAnnular Velocity, OptimumAnnular Volume, Open HoleAnnular Volume with Two lnner StriagsAnnulus, Starting Fluid, Iost CircApparent ViscosityArea I(nowledgeAvailable Pressure & HorsepowerAverage AngleAverage DirectionAzimuth Direction
BBack-OffBalanced ActivityBalancing GradientBalancing Mud Weight, [.ost CirculationBalanced PlugBarrels Per Day (BPD)Barrels Per FootBase Mud For I-CMBedding PlanesBentonetic Content (Bentonite Shale)Bentonite (Drill SolidslBentonite Ratio)BHP MaximumBHP Mud Weight EquivalentBit BallingBit PluggingBit Preszure DropBit Selection, LogsBlind DrillingBOP AccumulatorBottom Hole Assembly
Chapter XVIIChapter )OtrCbapter ruCIChapter XVIChepter, m, A-3Chapter )OOIChapter XD(Chapter XVIChapter [V, D; Chapter XVICbapter VII, HChapter VI, B, EChapter VI, FChapter XVIIChapter XVII; Chapter II, DChapter XVIChapter VII, BChapter XD(Chapter XD(Chapter XD(
Chapter )O(Chapter XVIChapter XVIIChapter XVIIChapter IV, GChapter )O(VIChapter m, A-3Qhapter XVIIChapter XVIChapter XVIChapter II, D4Chapter )CVChapter ){IVChapter XVIIIChapter XVIIChapter XVItrChapter X)iltrChapter XVIIChapter )CtrChapter XXII
A:1
Mu$:hison Drtllinq Sctrools. Inc. F
B (cont.)
Bottom Hole Presnre ReductionBoyle's General Gas I-awBreaking In BitBridgesBridging, Lost CirculationBubble GasBuild AngleBuilding Mud VolumeBuilding-The-NestBuoyancy FactorBuoyancy @iston) Effect
cCapacityCapacity of PipeCapillary ActionCasingCasing SeatCellophane Flake I-CMCementingCement MixCement PadCement PlugCement Required, I.C PIWCement TopCentrifugal PumpChange in AngleCirculating, Minimum RateCirculating Off Bottom PracticesCirculating Out Kick,Circulating Rate, Time & VolumeClosureCollapse Resistance CorrectionColloidal ContentCompaction TrendsCompletion Zone, L.C.Compress GasCompressibility VolumeConcentric Strings, CapacrtyConstant BHPContact TimeContamination, AvoidingConversion, TemperatureCorrelation, Logs
Az2
Cbapter X)ilVChapter )OOVChapter XVItrChapter Itr, A-5; Chapter XVIChapter XVIIChapter )OilVChaprer )OCIChapter )O(VChapter XVIIIChapter X)flI; Chapter XVIIChapter )OO(.B
Chapter VIChapter VI, DChapter XVIChapter IVChapter ry, BChapter X\flIChapter tVChapter VChapter VChapter IV, EChapter fV, IChapter IV, EChapter XtrChapter )(IXChapter XVIIChapter XVIChapter XVIIChapter fV, AChapter KXChapter )OOChapter XVIChapter XVIQhapter XVIIChapter XXVIIChapter fV, EChapter VI, EChapter X)(tVChapter fV, DQhapter IV, HQhapter X)fi.CChapter )Oiltr
FFFFFFFFFFaFFFFaFFaO;
FFaFF(F!It!!!IE!FFF!!!!
Murchison Drilline Schools, lne--
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
ta-
-
-
-
I
FBFFFFft.)
tt,.lt)tat)fatatt
C (cont.)
Course DeviationCoune kngthCritical VelocityCross-flowCross-sectional AreaCylindrical Taok Volume
DDensityDepreciation of E4ripmentDepth of Fluid LevelDepth to Top of CementDetection, KickDeviationDewater (Compaction) TrendsDiagram of FishDiamond BitsDifferential Preszure Across PackerDifferential Stuck PipeDifferential Test of LinerDirectional DrillingDirection, ProposedDispersionDisplacement RateDoglegDrag TrendDrift AngleDrift DiameterDrillabilityDritlability, From LogsDrill Collar Annular VolumeDrill Collar DesignDrilling JarsDrill Off Test -Drill Pipe DesignDrill Pipe PressureDrill Stem Testing (DST)Drill String DesignDrop AngleDry Pipe
EECDEconomic Disaster
Chapter KXChapter XD(Chapter XVI; Chapter MIChapter XVItrChapter )OilIChapter VI, C
Chapter tr, FChapter )OO(.DChapter XVIIChapter fV, EChapter )OCVChapter XD(Chapter XVIChapter )O(Chapter XVItrChapter )OilChapter XXChapter fV, JQhapter )ilXChapter )ilXChapter [, HChapter [V, DChapter )gXChapter IV, AChapter )OXChapter XVItrCbapter VII, AChapter )OilIIChapter KVChapter X)CIChapter X)ilIChapter XVItrChapter X)ilIChapter XVIIChapter X)ilChapter )OilIChapter X)OIChapter m, A-2
Chapter A,,A-2;Chapter VU, GChapter XX
A:3
Munchison Ihiltins Schools. Inc.
E (conr.)
Effective Collapse ResistanceEffect of Bit Weight & RPMElongation, Due to StrerchElongation, Due to TemperatureEncapzulationEquipmentEquivalent MWEqtrivalent MW at ShoeErosion of ShaleEstimating Gas Well Flow RateEstimating HP to Compress GasEstimating Production RateEstimated Snrck Point (ESP)Estimating Volume, Strokes, AnnulusExpozure Time
FFibers, I.CMField Mud, Building VolumeFinal Shut-In TimeFish & FishingFishing Days, Mudmum NumberFishing, EconomicsFlow ProfileFlowrateFluid l-evelFluid InssFluid to Fill HoleForce, Preszure Against AreaForce, Pump OffFormation TestFormulas, HydraulicFracture, Lost CirculationFractured ShaleFree PipeFulcrum (Irver)Funnel Viscosity
GGamma Ray I.ogGas Cut MudGas Expansion
A:4
Chapter )OOChapter )OilIChapter )OO(.8Chapter )OO(.AChapter XVIChapter X)ilVCbapter )OfiVChapter )CVChapter XVIChapter )O(UIChapter )OilfitrChaprer )O(VIChapter )O(Chapter )oOVChapter XVI
Chapter XVIIChapter )O(VCbapter ruCVChapter )O(Chapter )O(Chapter XXChapter XVIChapter VII, A, BChapter XVIIChapter tr, CChapter XVIIChapter )O(IVChapter XVIIIChapter )OilCbapter VII, BChapter XVIIChapter XVIChapter )O(Chapter )()CIChapter XVII; Chapter tr, C
;
sI;
;
;
F
Chapter )OilIChapter )OCVChapter X)ilV
;
;
s;
;
;
?sF;
;
a;
?;
s?ataQ
;
;
Fss;
;
7F;
TTIIa
Murchlson Drillinq Sclools. Inr.-
-
-
-
-
-
-
-
-
-
-
-
-
-
t)-
-
-
-
-
-
-
-)
-
-)
-D-atat)rlt.)
.)
-
f,
aarltat)t)'Dta
G (cont.)Gas FlowrateGas KickGas I-awGeneral Gas I:wGradientGradient, BalancingGradient, DifferenceGravel, Cement MixGuidelines, Hydraulic
Hllnmmel EffectHeaving ShaleHevi-Wate Drill PipeHold AngleHole CleaningHole RestrictionHoop StressHorsepower, Compress GasHorsepower, Compress GasHorsepower, SurfaceHydrationHydraulicsHydraulic, GuidelinesHydraulic, Mud Weight EffectHydraulics, OptimumHydrogen Sulfide (HrS)Hydrostatically, BalanceHydrostatic EquilibriumHydrostatic Pressure
IInitial FlowInitial Shut-In PeriodInner Strings, Annular Volume
JJar TensionJet HorsepowerJet SizesJet Velocity
KKCLKick Off PlugKick Tolerance
QheFter )OnmChapter )O(IVChapter )OilVChapter )O(IVChapter m, A4Chapter XVIIChapter IV-EChapter VChapter VII-B
Chapter XVCbapter XVIChapter )OtrIChaprcr )OflIChapter VII-DChapter XVIChapter XXtrChapter XXVItrChapter VII-BChapter VII-CChapter II-H; Chapter XVIChapter VIIChapter VII-BChapter Itr-FChapter VII-AChapter )OOChapter XVIChapter XVIIChapter VItr
Chapter X)flChapter X)ilChapter M-F
Chapter )OOICbapter VII-BChapter VII-BChapter VII-A, B
Chapter X\flChapter [V-G, HChapter IV-B; Qhnpter )ilV
A:5
rlurchison Drilling Schools. Inc. tL
Ianding Plug PreszurercMI.CM Baselrak-off Testkngth Qhangekngth, Drill Collar, Drill PiPekngth of InfluxIrngth Water for Testing LinerLiner TestingLocate Loss Zonelogs, Bit SelectionLoggtngIngs, Mud ProgramIosses, TotalInst CirculationLost Circulation, Cement PlugLost Circulation, No. 1 RuleIow Pressure OverbalanceIrrbricating Tecbnique
MMake-Up LossMargin-of-OverPullMarl, SEreezingMaterial BalanceMatting, Lost CirculationMaximum Allowable PresnueMaximum Equivdent Mud WeightMaximum Surface PreszureMaxinum Volume GainMBTMeasurcd Depth (MD)Mechanical Stick PiPeMetal DisplacementMica, LCMMinimum Circulating RateMinimum Discharge PreszureMinimum Effective Hole DiameterMinimum Yield StrengthMix RateMixing SubMix Water, CementMonel Drill CollarMonitoring Equipment
A:6
t
Cbaprcr II-C-?Chaprcr XVIIChapter II-C-?Cbapter )OVCbapter )OO(.A; Chapter )OO(.BChapter )OilICbapter )(IVChapter IV-JChapter IV-JChapter XVIICbapter )OilUChaprcr )OfltrChapter )OgtrChapter XVIIChapter XVIIChapter IV-lChapter )OruCbapter Itr-A-sCbapter )OilV
Cbapter )OChapter )OflICbapter XVIChapter )OffChapter XVIIChapter )ilVChapter )ffIChaprcr )OilVChapter )OgVChapter XVIChapter XD(Chapter )O(Chapter m-A-3Chapter XVIIChapter XVIIChapter )iltrChapter )OgICbapter )OO; Chapter )OgIChapter w-DChapter XVIIChapter tV-CChapter )OAIChapter )oilV
!ttttttt?ttt?!C;
Ittf;
tt?ttttIteeItI
tItItt
Murchisnn f)rillins Sclrnok- fnc.-q
-
-
-
-
-
-
-
.a-
'Dta-
-
'D-
-
-
-
-
-
-
-)
.)
-,
a.)
.)
,,
t)a,tlf)
1)If,fl
Ia,a.
'D-
M (cont.)Motor, MudMud Balance, Tnr WateMud, Gas CutMud MotorMud Programs, I-ogsMud Weight, BalancingMud Weight QhengeMud Weight EquivalentMud Weight, Slug Mud WeightMud Volume Building
NNegative Side ForceNeunal PointNitrogen PrechargeNon-magnetic Drill Collar
o
Oil Base Mud CompressibilityOil MudOil Mud, Building Volume, Pilot TestsOpen Hole VolumeOperational PlanOperating Practices, Directional WellOperational SuccessOptimizing, LogsOsmotic HydrationOverbalanceOverburden Pressure
PPendulum BHAPendulum ForcePercent Preszure at BitPercolation of GasPipe CapacityPipe Make-Up LossPipe Size, HydraulicsPipe, StrerchPipe, SnrckPiston, Buoyancy EffectPlastic Shale
Chapter IV-EChapuir XVICbapter )OffChapter VI-AChapter XXChapter )fiXChapter XXChapter )OtrtrChapter XVIChapter Itr-A-5; Chapter II-A-1Cbapter XVI
Cbapter )OCIChapter )OilIChapter VII-BChapter )O(IVChapter VI-DChapter )OChapter VII-EChapter )O(Chapter )O(Chapter )OO(.BChapter XVI
Chapter )OilIChapter XVIIChapter )O(IVCbaprcr )OflIChapter )OCnChapter XVIIChapter IV-BChapter )O(IVChapter m-A-lChapter )OW
Chapter )OilIChapter )OilIChapter )fltrChapter X)CI
L:7
P (cont.)Plastic ViscosityPlugging, Bia with I,CMPIug, CementPlugging FracorresPlug SeningPolycrystalline Diamond CuuersPolymer MudPorosity GasPorosity IngsPotassium ChloridePre Flush SpacerPressure AllowablePreszure at Bit (Planning & Actual)Pressure, AvailablePreszure Difference (AP) to Ifld PlugPressure Differential Across PackerPressure DropPressure Loss, Effecxt of MW & PVPreszure, Effect of Pipe SizePressure, HydraulicPressure, HydrostaticPressure LossPressure, Maximlm SurfacePreszure, OverburdenPreszure Reduction with IrrbricationPressure Regular, Temperature DropPressure, Stroke RelationshipPreszure, Surge & SwabPreszure to Land Cement PlugPreszurized Mid BalanceProduction, Estimating RatePulling-out-of-HolePulling Test Tools OutPump Off AreaPunp Off ForcePump Ouput
aQ, FlowrateQ, MinimumQuadrant Direction
RRadial FlowRatioactive SourceRate of Percolation
A:8
QheFter tr-B; Chapter VII-FChapter XVIIChapter tV-EChapter XVICheFter IVChapter XVItrChapter XVIChapter )OOVChapter )OiltrChapter XVIChapter IV-DChapter )ilIIChapter VII-BChapter VII-BChapter IV-E, HChapter )OCChapter XVItrChapter VIII-FChapter m-ECbapter VIIChapter MtrChapter tr-A; Chapter Itr-A-2Chapter )OCVChapter XVIChapter )OCVChapter )O(D(Chapter VII-DChapter m-81Chapter IV-Echapter xvIIChapter )O(D(Chapter Itr-Achapter )oflCbapter XVItrChapter XVIUChapter [V-E
Chaprer VII-BChapter XVItrChapter XD(
Chapter XVItrChapter )OiltrChapter )OilV
!I!T:
!!F!!FFFF;
FFFtFF!It
Ft(tttI!!!!rr!
rrI
I
J
Murchison Ihillins Sctrools- Inta'D-
-
ta'Dt)t,-
-
-
-
ta-
)
)
.ltta.)
II
rtrtt)t)rll|
ttrttfla),)
f)
ft
R (cont.)Ratio, SIVSTRatio TechniEteRectangular, CoordinatesResistivity LogRestriction, HoleReverse Test for LinerRope StrenglhRoughneck FormulaR.P.M., EffectRunning Test Tools
sSafe Exposure TimeSafety FactorSafe S/ater SpacerSalinity, OsmosisSand, Cement MixSealing, Lost CirculationSection DifferencesSetting the PackerSet Down Weight, Irngth QhangeShaleShale HydrationShale Percent from LogShale Transition TnnesShoe, CasingShoe PressureShut-in Casing Pressure (SICP)Shut-in FinalSlip CntshingSlipping of PackerSloughing ShaleSlug Mud WeightSnubbing/StrippingSolidsSolids Control, Lost CirculationSonic I-ogSpacer WaterSPMSqueezing MarlStabitity ShaleStabilize, Diamond BitStabilizing, HoleStarting Fluid in AnnulusSteel Cable
Chapter )OtrIChapter )OilVChapter XD(Cbapter )OiltrChapter XVIChapter IV-ICbapter XChapter VII-DChapter )OfiIChapter )OO
Chapter XVIChapter )OilIChapter IV-GChapter XVIChapter VChapter )ffIIChapter XD(Chapter )OilChapter )Ofi.BChapter XVIChapter tr-HChapter )O(ItrChapter XVIChapter fV-BChapter )OOV; Chapter XIVChapter )OVChapter )OilCbapter )OOIChapter )OilChapter XVIChapter m-A-1Chapter ru(IVCbapter tr-EChapter XVIIChapter )O(IUChapter IV-D, GChapter MI-D; Chapter XVICbapter XVIChapter XVIChapter XVItrChapter IV-AChapter XVIIChapter D(
A:9
Murchison Drillins Schools. Inc. t
S (cont.)Stiffiness RatioStrength of RopeStrength of Steel CableStretch, ElongationStrerch of PipeStripping/SnubbingStrokes to Bump PlugStrokes to Move Bubble to ShoeStrong Surface BlowSilck PipeSuppress TirbulenceSurface HydrationSurface LocationSurface PressureSurface SystemSurge, Operational PracticeSurge PressrueSwab Pressure
TTapered StringTarget IocationTemperature ConversionTemperature DropTemperanue ElongationTen'D" RuleTensile StressTension on PipeTest, DrilloffTesting LinerTester ValveTime ExposureTime, Suck PipeTolerance, KickTop Hole Iost CirculationTop of CementTotal l,ossesTransition ZoneTrends, Directional WellsTrip MarginTrippingTrue Vertical DepthTrue Weight on BitTru-Wate Mud Balance
Chapter )OilICbapter XChapter IXQhaFter )OO(.BChapter )O(Cbapter )OilVChapter IV-EChapter )OilVChapter )O(IChapter )O(Chapter XVIChapter XVIChapter XD(Chapter fV-HChapter )OilVChapter XVIIChapter m-B-1Chapter m-B-1
Chapter XXChapter XD(Chapter X)O(.CChapter )OOXChapter nO(.AChapter VII-CChapter )OilIChapter )O(IChapter XVItrChapter tV-Ichapter XXIChapter XVIChapter XXChapter )ilVChapter XVIIChapter IV-EChapter XVIIChapter XVICbapter )OXChapter tr-A- 1 ; Chapter Itr-A-4Chapter Itr; Chapter XVIChapter XD(Chapter XVItrChapter XVII
I!
TttttFFt!FF!!Jt!tJFttattItJIt!
!
!(!
!
!
I
I
I
!
I
II
A:10
Murchison Drillins Schools. Inc)
-
-
-
-
-
-
-
-
'D)
ta)
t-
ttatpFFFFl-
r-
BFFFrltrD.l-
tD.la-^
a-
-
a
UUnseating PackerU-Tube Presnue
vVelocity, JetVertical SectionViscous Mud, I-CM BaseVolumeVolume, AnnularVolume, BuildingVolume Cement for LC PlugVolume, CompressibilityVolume, Concentric StringsVolume, Cylindrical TankVolume, Maximum from Circ Gas BubbleVolume of Mud to letVolume, Open HoleVolume, PipeVolume Sizing of AccumulatorsVolume to Bump PlugVolume to llbricateVolumetric Method
w
Walk, Right &I'eft HandIValnut HullsWater Base vs. Oil Base CompressibilityWater Hammer EffectWater LossWater, MixWater Spacer, SafeWeak Surface BlowWeight, Air & BuoyancyWeighted MudWeight on Bit, DC DesignWeight on Bit, TrueWeigbt per Foot, DPWet PipeWorking Strengttr
Chapter VII-A-BChapter )OXChapter XVIIChapter VIChapter VI-BChaprer )Oil/Chapter IV-IChapter IV-FChapter VI-EChapter VI€Cbapter )OflVChapter XVIICbapter VI-AChapter VI-DChapter )fitrChapter IV-EChapter )O(IVChapter )OCV
Cbapter )OOCbapter IV-H
Chapter )Oil'Chapter XVIIChapter IV-FChapter XVChapter tr-GChapter IV-CChapter IV-GChapter X)oCbapter )OilIChapter II-E-?Chapter )O(IIChapter XVIIICbapter )O(IChapter m-A-2Chapter )ofiI
Chapt€r tr-AYield Point
A:11
)
t,'Daaaaaaa-
ta1,aaftL
ataaaaItaaaaaItaI|
ItIIaaataaa
AV
B
BF
BPD
B.O.P.
ccc
GPM
cps
d
DCIP
Dh
DP
De
ds
ds/b
DST
DV
e
ECD
E.S.P.
F
FC
FCP
ft
FSI
FV
FVo,n
G
GM
Gri,,
ffi. APPENDIX BABBREVIATIONS
-- Average Viscosity
: Bit Diameter, inches
: Buoyancy Factor
= Barrels per Day
= Blowout Prevention (Equipment)
= Coarse Solids, ppg, > 1 micron
: Cubic Centimeter
= Gallons per Minute
= Centipoise
: Hole Diameter, ins
: Dual Closed-In Preszure (Tool)
= Diameter of Hole, ins
= Drillprpe
: Diameter of Pipe, ins
= Drill Solids, ppb
: Drill Solids/Bentonite Ratio
= Drill Stem Testing
= DV Cementing Collar
= SEetch, inches
: Equivalent Circulating Pressure, ppg
: Esinated Stuck Point
= Fine Solids, ppb, ( 1 micron
= Float Collar
= Final Circulating Pressure, psi
: Feet or Foot
= Final Shut-In
: Funnel Viscosity, sec/qt
= Minimum Funnel Viscosity
= gpm, Gallons per Minute
: Mud Gradient, psi/ft
: Minimum G
B:1
IMurchison lhitline Schools. Inc.
HIIP
HIIP/in2
hr
HrO
vcICP
in(s)
JT
J"
L
lb(s)
L.C.
LCM
LCMb.r"
kn
L.O.T.
M
t@T
MD
M.O.P.
MW
Mwb.l
MW"
MwE
MwF
Wfo-."qui".
Mwh
wno,"
MWo
Mwr
MWu
NP
OPT
Hydraulic Horsepower
Hydraulic Horsepower per Square Inch
Hour
Water
Stiffness Factor
Initial Circulating Pressure, psi
Inch(es)
far Tension
Jet Velocity, fl/sec
Pipe I-ength, ft
Pound(s)
Inst Circulation
Lost Circulation Material
Base LCM Mud
I-ength, ft
Irak Off Test (At Casingshoe)
Mud
Methylene Blue Test
Meazured Depth, ft
Margin of Overpull
Mud Weight, ppg
Mud Weight to Balance Formation Pressure, ppg
Cut Mud Weight, ppg
Mud Weight Equivalent, ppg
Mudweight of Feed, ppg
Equivalent Mud Weight of Formation Pressure
Mud Weight in Hole, ppg
Mud Weight in Use Prior to Running I-ast Casing
Uncut, Original Mud Weight, ppg
Trip Mud Weight, ppg
Underflow Mud Weight, ppg
Neutral Point
Optimum
I
-
I
J
f
J
af
taJ
J
J
J
J
I,
J
IJIFF,
,
F€
ttttItFIE
EE]uEFIE(E
t
B:2
I)
t P : Overpull
, PrP, : First, Second Gas pressures
) P_o : pressure Loss in Annulus, psi
) poo = pressure Ioss Across Bit, psi) AD r-^--^-+^r / \ - -^- t -^r- -^- - - - - - ,
) Apob : Incremental Overbalance pressure, psi
, POH = pull Out of Hole
) ppf = Pounds per Foot or lb/ft
) ppg = Pounds (Weigh0 per Gallon (US)
) PSI : Hydrostatic pressure, psi
) P*,r = pump preszure, psi)
) Prrr* : All heszure Losses
I PV = plastic Viscosity
) PVn*n : Maximum plastic Viscosity
) W,o* : Minimum Plastic Viscosity
) qt : euarr (US)
) RIH = Run in Hole) ROp = Rate of penetration, ff/hr)
) rpm = Revolutions per Minute
) se" : Second(s)
) SF : Safety Factor
) SIDPP : Shut-In Drill Pipe Preszure, psi) sot : Solids) sptn = Strokes per Minute)
) TS : Total Solids, ppg
I TVD = Tnre Vertical Depth, ft
) v = Annrlar Velocity, ff/sec
) VrVr : First, Second Gas Volumes) V- : Compressibility Volume for an Oil Base Mud) _
) V* = Compressibility Volume for a Water Base Mud
, Vo" : Openhole Volume, bbls
) WH : Wellhead
i _;; =;ffi,T;;_B:3
Murrlison Ihillins Schools. Inc.
Y? : Yield Point, lbs/100 sq. ft.
F/ : Yield Value, lbs/100 sq. ft.
e0300 = Fann Viscometer Reading at 300 rpm
e0600 : Fann yis*-"ter Reading at 600 rpm
1500 : Weight of Barite, ppg
2748 : Weight of Steel, ppg
FFFIFFFFIFaaFaafc(
cdIJlJdJl{
IaI
-
-
-
-
Ir!-
IrIEEI!,
Bz4
Murchison l)rillinp Selools. Inc.
SI METRIC I]NITS
A. SI METRIC CONVERSION FACTORS
x 3.281
x 6.894 757
x 22.62
x 2.54
x 3.785 412
x 1.589 873
x 16 .02
x 1 .198 264
x .00379
x 6.309 020
x 1.489
x 1 .0
x 4.788 026
x 2.853
x .794
x 1 .355 818
x .5216
x 4.448 222
x .445
x 7.460 43
x 1.745 329
fioF-321/1.8
x 9.290 304
x 2.831 685
IaaIaaaaIaaaaaaattItIttDttttttIIDtttItttt)
)
1 . f t
2. psi
3. psi/ft
4. in.
5. gal
6. bbl
7. lbs/cu ft
7. lbm/gal
8. gal/min
8. gal/min
9. rb/ft
. 10 . cp
1 I . lbf/lOOft'z
12. rb/bbl
13. 32 's in
14. ft-tbf
15. bbr/ft
16. tbf
16. tbf
17. hp
18. deg
19 . oF
20. tr
21. ft3
m
kPa
kPa/m
cm
m3
mg
kg/m3
kg/m3
m3/min
m3/s
kg/m
Pa's
.Pa
kg/m3
mm
Torque(M.n)
m3/m
N
daN
kw
rad
ToC
m2
m3
E-Ol =
E+00 =
E+OO =
E-03 =
E-Ol =
E+O2 =
E-05 =
E-03 =
E-01 =
E+OO =
E+00 =
E+00 =
E-01 =
EO2 =
E-Oz =
E-Oz =
C:1
22.
22.
23.
24.
25.
26.
27.
27.
28.
29.
30.
31 .
32.
33.
34.
inz
tn'
lbm
miles
atrn
kip
ton
ton
ftlmin
ftlhr
cuf t
bar
sack
cflsk(yretdl
'Fll 00 ft
E+OO =
E{4 =
E-01 =
E+OO =
E+O2 =
E+03 =
E-ot =
E+02 =
E-03 =
E-05 =
E-O2 :
E+OS =
E-O2 =
E-O2 -
E+01 =
cm2
m2
kg
km
kPa
N
Ms
kg
m/s
m/s
m3
Pa
m3
me/sk
mK/m
6.451 6
6.451 6
4.535 924
1.609 3,f4
t .o t3 250
4.448 222
9.071 847
9.O7r 847
5.080
8.466 667
2.831 685
1 .0
3.1 14854
3. t 14854
1.822689
IIIIIttttIt|l]
;
;
!1S]Faa;
-
F;
I-E
I
i-
-rIIrIrtE
C:2
TABLE OF CONVERSION FACTORS. ENGLISH UNITS TO METRIC UNITSB.
3A
-
-
-
-
-
-
-
-
-
-
-
-
t,tttt-
-f-
-
.tF|t-
!-
aIf,tIt-
I-
-)
rt-D.tt).tt)faat{
25.4 mm0.3048 m
0.0046 m3
O.OO379 m30 .159 m3
6.895 kPa
0.0046 m3/min0.00379 m3/min0.1590 m3/min
99.78 kg/m31 19.83 kg/m3
2.853 kg/m3
1.489 ks/m
1.057 sA
mPa's
0.4788 Pa
0.4788 P
0.3048 m/min
14.317 MJ
0.445 daN
0 .1589 m3
0.177 m3/m3
1.0
25.4 mm+inch0.3048 m+ft
1 gallon(Canadianl1 gal(U.S.l1 barrel 142.05US gall
0.0046 63-+gal
0.00379 6t-rgal0 .159 mt+bb l
6.895 kPa +lb/in2
I gal(Cdnl -rmin1 gal{US}-rmin1 bbl-+min
0.0046 m3/min+gal/min0.00379 mr/min + gal/min0.1590 m3/min+bbl/min
Density:(mud wt)
1 161Qsln) - palI tb (USl + gal1 lb (USl - bbl
99.78 kg/cu m+lb/gal119.83 kg/cu m+lb/gal2.853 kg/cu m+lb/bbl
1 .489 kg/m: lb/ft
1.057 sec/L+sec/qt
1 mPA/sec+centipoise
1 lb- 100 sq ft 0.4788 Pa+lb/l00 sq ft
1 lb: 100 sq ft 0.4788 Pa+lb/l00 sq ft
0.3048 m/min-rft/min
1 4.317 megajoules + ton-mile
0.445 deca-newtons + lbs
0.1589 cu meters+bbl
l s t dcu f t(gasl+1 bbl oi l
0.454 kg - lb 0.454 kg
Murchison Dri[ins Schools. Inc.
mega (M)kilo (klhecto (h)deca (daldeci (dlcenti (c)milli (ml
eg.1 kilounit x 1OO0
Note: :
: multaply by 1 O0O OO0 (millionl= muhiply by 1 OOO (thousandl= multiply by 100 (hundredl= multiply by 10- multiply by 0.1 (one tenthl= multiply by 0.Ol (one hundrethl= multiply by O.OOI (one thousandth)
= 1 megaunit
Ft:
:
!ttFtIatFTIIrlF!!at!at;
!!!!I!!IIIIII!I!!
ln Metric M means million not 10OO as in English units.ln Metric use k for l OOO
depths must be to nearest one tenth of a metre (mlon casing and tubing convert O.D.'s to nearest one tenth of a millimetre (mmldo not convert nominal sizes
B. (Continued} TABLE OF CONVERSION FACTORS. ENGLISH UNITS TO METRIC UNITS
Metric Unit
1032.04 kg/m3
1032.04 ks/m3
0.00756 m3/min
15 200 kPa
44.19
Metric Unit
139 .7
304.8
Bit Sizes & Bit Jets: Security Rock Bit Metric Conversion Chart - See Section E.
SOLIDS REMOVAL
wt o.F. flb/gaD: 8.6 lb+-gal
Wt U.F..{ lb/sal}: 9.6 l !+ga l
0.00378 m3/min+ gal/min
6.895 kPa+1 lb/sq in
145 f t+min 0.3048 m/min:1 ft/min
PUMP ON HOLE
25.4 mm+inch
25.4 m+inch
Bit Weight: 4O,OO0 lbsNote: In thousands (17.8 daN)
0.445 decaNewtons+ 1 lb
C:4
17,800 daN
MrrrehionDrillinoSnhmle fnrt-.
-
-
-
-
-
-
-
t-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
aII{
ftrt-
.)
.)
t)ttt)tta,tta-
-
)
8. (Continued) TABLE OF CONVERSION FACTORS - ENGLISH UNITS TO METRIC UNITS
Enolish Units
Hydrostatic Pressure (HPl: = Mud Weight (ppgl x 0.052 x Depth lftl
Example: 9.0 lb/gal x 0.052 x 10.000 ftHP = 4680.0 psi g
Metric Units
Hydrostatic Pressure (HPl: = Mud Weight (kg/mrl x Depth (61 + 100= 1078.44 kg/mt x 3048m + lOO = 32870.9 kPa
Note: 32870 kPa = 32.87 MPa
c. Examole of Drillino Data Converted from Enolish to Metric Units
HYDROSTATIC PRESSURE
Total Depth 14009 ft x 0.3048 m+ft 4269.9 m
Progress 41 ft x 0.3048 m+ft 12 .5 m
Mud Weight g.g l ls+gal x 120 kg/m3+lbs/gal 1056.00 kg/m3
Viscosity 59 sec+qt x 1.057 secA+sec/qt 62.00 sA
Waterloss(WL) Remains the same (cubic centimetresl cm3
PH Remains the same
PV 20 centipoise x 1 millipascal sec-l centipoise 20. mPa's
YP 15 lbs+ 1O0 sq ft x 0.4788 pascals+ 1 lb/l00 sq ft 7.2 Pa
Gels 2 lbs/l00 sq ft x 0.4788 pascals+ 1 lb/l00 sq ft 1 .0 Pa
% Solids Remains the same
Chloride Remains the same
Calcium Remains the same
% oil Remains the same
Water Added 1 barrel x 0.1 589 cubic metres+bbls 0.1589 m3
BHTO oc
Solids(lb/bbll 1 5 l b + b b l x 1.853 kg/m3+-lb/bbl 27.795 kg/m3
C:5
Murciison Driltins Sclools. Inc. FFFFFFFFaItF€
F]F€
Ce]FFaOaaaFFtTI!II!IIIIIIII-
I
METRIC CONVERSION TABLEC. (continuedl
Drillino Data
APPLICATION TRADITIONAL CONVERSIONFACTOR
(METRICISI UNIT
METRICSYMBOL
Bit Size inches x 25.4 millimetre mm
Weight on Bit pounds x .445 decaNewton daN
Depths (drilling, casing, etcl feet x .3048 metre m
Nozzle size 32's of an inch x .794 millimetre mm
Annular Velocity feet per minute x .3048 metre/minute m/min
Jet Velocity feet per second x .3048 metre/second m/s
Pumo and Hvdraulics
APPLICATION TRADITIONAL CONVERSIONFACTOR
(METRIC}SI UNIT
METRIcSYMBOL
Liner, Stroke Length& Rod Diameter
inches x 25.4 millimetre mm
Output gal/minute x .00379 cubic metres/min m3/min
Pump pressure lbs/sq inch x 6.894 kilopascal kPa
Mud Volume barrels (US) x .159 cubic metre m3
Mud Weight lbs/gal (USl x 119 .8 kilogram/metre3 kg/m3
Capacities-(Ann, dp, etc.) barrels/ft (US) x .5216 cubic metre/metre m3/m
DensiW lbs/cu ft x 16.02 kilogram/cubic metre kg/m3
Pressure Loss psi/ft x 22.62 kilopascal/metre kPa/m
C:6
-.
-
-o.-
-
-
ta-
tt-
-
-
-
-
-
-
-
-
-
-
.t
.)
-,
-D.taataataftJ'
t,f)
f)
t,
t)
f0ttataa)a
ENGLISH AND AMERICAN UN]TS
VALUE
NAME SYMBOL REIATIVE IN METRIC UNITS
LcngthInch {poucelFoot (piedlYardFathom (brasselMile (statutelMile (nautical)
inftyd
12 in3 f t2vd
1 760 yd2029 vd
(metrel0.02540o.304790.914381.82876
1609.31491853.1232
AreaSquare inchSquare footAcreSquare mile (stat.l
sq insq ft
sq mile
144 sq in4840 sq yd640 acres
(squarc metrel0.000645130.0928997
4046.81259.0 ha
. VolumeCubic inchCubic foot
cu incu f t 1728 cu in
(cubic metre)o.o000163860.02831531
CapacityGallon (USlBarrel of'oil
sal (uslbbl 42 gal (USl
(litrel3 .785
158 .98
MassOuncePound (livrelTon (short tonl
oztb
sh tn16 oz
2000 lbs
(kilogrammel0.0283s0.453593
907.1853
MISCELI.ANEOUS CONSTANTS
0.0764 air density in lb/ft3 at 6OoF and 14.6 psia
14.691 normal atmospheric pressure (76 cm Hgl in psi
32.174 gravity acceleration in fUs2 980,665 cm/s2
550. number of lb ftls in one horse power (hpl
778.2 number of lb in one Btu
62.43 water density in tbf/cu ft at 4oC
8.34s water density in lbf/gal at 4oC
oC + 273.16 oK lKelvinloF + 459.69 oR (Rankine)
C:7
METRIC CONVERSION CHART
BIT S IZE NOZZLE SIZE CASING S IZE
lnches Mil l imeters(mm) Inch'es( 32rs) Mill imeters Inches Mil l imeters
4-3/4
s-7186
6-1 /8
6-1 / r t
6 -112
6-s /8
6-3/q
7-318
7-s l8
7-718
8-3 /8
s - l t2
8-s /8
8-3 /4
9
9-112
9-s /8
9-7 l8
10-s l8
t t
l 2
12-1 I 4
13-112
t 3-3i 4
t4 -3 /4
l5
l5
17-112
t 20 .6
t {9 .2
t 52. rt
15s .5
158 .7
165 .1
168 .3
17 r .4
187 .3
t93 .7
200 .0
212.7
215 . 9
219 .1
222.3
228.6
241 .3
244 .5
250 .8
269 .8
279.4
304 .8
311 .2
342 . 9
3q9 .3
374.7
381
406 . l l
444 .5
7
8
9
10
I t
12
13
ltt
15
l 6
18
20
22
24
26
28
5 .6
6 .4
7 .1
7 .9
8 .7
9 .5
t0 .3
l 1 . t
11 . 9
12.7
14 .3
r5 .917 .5
19 .1
20 . 6
22.2
4-112
5
s- l12
6
6-s/87
7-S l8
8-s/89-s /8
10-3 /4
1 l - 3 /4
r 3-3/8r620
114 .3
127
t39 .7
152 . 4
r68.3177.8
193 .7
219 .1
2rr4.5
273.1
298 .5
339 .7
406 . 4
503
FFFFFFFFFFFFFssFFaaFFaaFFF;
!rI!TIF!TIIIr7
C:8
Mrrrlhicnn Drlllino Sehrnlc- fnc
WHERE METRIC CONTROL DATA APPLIES
BOPE PUMP AND CIRCULATING SYSTEM
SIDPP
Summary OfWeak Links
Rupture
W/Gas = KPa
lV/Mud = KPa
Csg. KPa
@-*Floor
Pump Output x
m3/stk.
Drilling €_spm==
€ sPm= r3/r i r , . =
r3/r i r r . =
€ sPm= r3 / r in . =
Reduce{,0 -m-
M in .
r3/rirr.
KPa
Reduced (A)
Reduced (B)
Reduced (C)
KPaTotal Mud
VolumeB.O .P .
Other
Hvdrostatic €Mud Column
Rupture GradientKPa/m
Formation Intake Pressure
KPa csg. m Grade
Burst
K ICK DATA
SIDPP stcP Pit Gain U, t . lnc.
Mixing Rate Sax/Min. In
New Mud Wt. To Ki l l SIDPP
Trip Margin(Overbalance Safety Margin)_
Wt. Inc . Mixing Rate Sax /Min. I n ._.,ltlin .
Final Mud Weight
lnit ial Circulating
Main Hole Size =
Pressure ,FCP
mm
KPa
Shoe WithKPa
Backpressure with Mudin Casing KPa
Numbers
CaP. =
Cap. = r3 / t
Standard
Ann. Vol .
Volume
Total Depth
r3 / too t
KPa
) r t l l t nq- rn-rlnrir.
Hydrostatic Pressure
Formation Pressure
C:9