07 directional drilling

8/10/2019 07 Directional Drilling

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DIRECTIONAL DRILLING

The well bore is deliberately deviated from the verticalalong a predetermined course to a target reservoirOBJECTIVES:

• Multi wells from Single Structureand/or location

• Shoreline drilling• Fault control• Inaccessible location• Stratigraphic traps (Salt dome)

• Relief well control• Sidetracking off the

obstruction (fish)• Deviate well course to more

promising target (s)



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Type I Type II Type III



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DIRECTIONAL DRILLING TOOLS

JETTING BIT

1. One nozzle is fully blanked (big Boy), the rest

are plugged or restricted

2. Orient the blank nozzle to designed direction3. Jetting the formation with hydraulic and with

none rotating pipe

4. Once the deviated hole pattern have been

formed, rotating pipe to make a new hole

5. Repeat the jetting/rotating sequence until

inclination is achieved

6. Good for soft and unconsolidated formations

7. Good for anti-collision purpose

Steps



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DOWNHOLE MOTOR WITH BENT SUB

BENT SUB was used in earlyStage when Down hole Motor

had first been introduced.

It was presently an obsoletetool in directional drilling dueto the limitation of rotating thepipe combine with an advancedTechnology on down hole Motorsof which extensively high efficiencyand more steerable friendly.




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DOWNHOLE MOTOR (STEERABLE)


BENT HOUSING SUB) FIXED ON THE BODY



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Flow

Rotation

DownholeTurbodrill

Turbine motors are used both for directional drilling and straight-hole drilling.

A turbine-type motor

Driven by the drilling fluid

- like the PDMMulti-stage blade-type

stator and rotor sections

A thrust bearing section

A drive shaft



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Top Sub

Turbine Section

Bearing Section

Stator/Rotor-

One Stage

Rotor (Rotating)

Stator (Stationary)

Turbine Section

Typical

turbine

design.

PDC or Diamond Bit



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DownholeTurbodrill

Number of rotor/stator sections

may vary from ~25 to 250

Stator remains stationary - itsmain function is to deflect the

mud to the rotor blades

The rotor blades are connectedto the drive shaft, which is

connected to the bit



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MAIN COMPONENTS (Top to Bottom)

•Top Stabilizer (optional)•Bypass Vale•Flexible Bent Sub (optional)•Rotor/Stator Housing (power sub)•Flexible Bent Sub (Standard)•U-joint Housing

•Bearing Assembly Housing (outsideBody is Near Bit Stabilizer)

•Bit Box

MWD



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INSIDE

OUTSIDE



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Building

Hole Angle



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Holding

Hole Angle



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MONITORINGDIRECTIONAL DRILLING

PRESENT TECHNOLOGY

FOR ROTARY ASSY.



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LATEST TECHNOLGY

FOR DIRECTIONAL DRILLING

An advanced BHA that steers itself During continuous drill string.

Electronic control 3-pad Stabilizer onthe sleeve which is programmed wellPath controlling.More smooth in well bore than drillwith Motor.

Product Propaganda

“Auto Trak” - Baker Hughes

“Power Drive” – Schlumberger

“Geo-Pilot” – Sperry Sun, Halliburton

ROTARY STEERABLE SYSTEM



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LATEST TECHNOLGY

FOR DIRECTIONAL DRILLING



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Tool Face Angle



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Inclination Angle

q a

, I

Direction Angle

f e

, A



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N18E

N55WS20W

S23E Azimuth

Angle



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Directional Drilling Measurements

• The trajectory of a wellbore is

determined by the measurement of:

inclination q, a, I

direction f, e, A

measured depth DMD, DL, L



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• A tool-face measurement is

required to orient:

A whipstock

The large nozzle on a jetting bit

A bent sub or bent housing



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• Tools available

Single-shot magnetic or gyroscopicMulti-shot magnetic or gyroscopic

Magnetometers, accelerometers,

MWD tools



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Survey Methods

• Single-Shot



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• Steering Tools

Survey Methods



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Steering Tools:

• When a mud motor with a bent sub isused, it may be more economical torun a steering tool than tocontinuously run magnetic singleshot surveys.

• An instrument probe is lowered by awireline unit and is seated in themule-shoe orienting sleeve.



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Steering Tools - cont’d

• The wireline can be passed through acirculating head mounted on thedrillpipe. Every 90 ft the tool is

retrieved so another stand of pipe maybe added.

• Alternatively, a side entry sub may beused for the wire. A stuffing box thatprevents fluid leakage is built into theside of the sub.



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• Most steering tools continuouslysense

– inclination– direction

– tool-face angle



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• The steering tool takes the guess-workout of correcting the tool-face angle forreverse torque.

• A steering tool is one of the mosteconomical means of making a trajectory

change when a mud motor and bent subare used for drilling, especially when rigcosts are high.



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MWD(Measurement While Drilling)

• While drilling it is possible to transmit tothe surface downhole information on:

inclination temperature

direction weight on bit

tool-face angle torque on bit

gamma ray sonic velocity

resistivity



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MWD - cont’d

• Inclination, direction, and tool-face angle areof particular interest in directional drilling. Alower cost MWD tool can be used if onlydirectional drilling information is required.

• Information is typically transmitted throughthe mud column by:

• + ve or - ve pressure pulses, or• pressure pulse modulation



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Basic types of mud pulsers

~ 3-5 minutes per update



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Basic types of mud pulsers

Mud Siren - 0’s and 1’s



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In the BUILD

Section

Dx = r (1 - cos I)

D

y = r sin I

DL = r Irad

degIr 180

=L ÷÷

÷÷÷

÷ pD

BUR*

000,18r

p

=

Dx

Dy

I

I

r

r DL



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42131 xr r andxr



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CLOSURE

LEAD ANGLE

(HORIZONTAL) DEPARTURE



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• Average Angle

• Balanced Tangential

• Minimum Curvature• Radius of Curvature

• Tangential

Wellbore Surveying Methods



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Example - Wellbore Survey Calculations

• Point C has coordinates:

• x = 1,000 (ft) positive towards the east

• y = 1,000 (ft) positive towards the north• z = 3,500 (ft) TVD, positive downwards

Dz

E (x)

N (y)C

DDz

N

D

C

Dy

Dx



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Example - Wellbore Survey Calculations+

• I. Calculate the x, y, and z coordinatesof points D using:

• (i) The Average Angle method• (ii) The Balanced Tangential method

• (iii) The Minimum Curvature method

• (iv) The Radius of Curvature method• (v) The Tangential method



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Find the coordinates of point D using

the Average Angle Method

At point C, x = 1,000 ft

y = 1,000 ft

z = 3,500 ft

80 A 24I

20 A 14I

DD

CC

=

=

ft400MDD,toCfromdepthMeasured =

The Average Angle Method



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80A 24

20A 14I

ft400MDD,toCfromdepth

D

CC

==

==

=D

D I

Measured

Dz

E (x)

N (y)

C

DDz

N

D

C

Dy

Dx



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This method utilizes the averageof I1 and I2 as an inclination,the average of A1 and A2 as adirection, and assumes the

entire survey interval (DMD)to be tangent to the averageangle.

2

III 21AVG

=

2AAA 21

AVG =

AVGAVG AsinIsinMDEast D

AVGIcosMDVert D

AVGAVG AcosIsinMDNorth D




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AVGIcos400Vert =

cos19400z =

AVGAVG AcosIsinMDNorth D

ft84y =D

50cossin19400y =

ft 378z =D




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• At Point D,

• x = 1,000 + 100 = 1,100 ft

• y = 1,000 + 84 = 1,084 ft

• z = 3,500 + 378 = 3,878 ft




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The Balanced Tangential Method

This method treats half the measureddistance (DMD/2) as being tangent toI1 and A1 and the remainder of the

measured distance (DMD/2) as beingtangent to I2 and A2.

2211 AsinIsinAsinIsin2

MDEast =

2211 AcosIsinAcosIsin2MDNorth =

12 IcosIcos

2

MDVert =



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DDCC AsinIsinAsinIsin2

MDEast =

oooo 80sin24sin20sin14sin2

400

ft x 97=D



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DDCC AcosIsinAcosIsin2

MDNorth =

oooo 80cos24sin20cos14sin2

400

ft y 60=D



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CD IcosIcos2

MDVert

=

oo 14cos24cos2

400

ft z 377=D



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• At Point D,

• x = 1,000 + 97 = 1,097 ft

• y = 1,000 + 60 = 1,060 ft

• z = 3,500 + 377 = 3,877 ft



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Minimum Curvature Method



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)2080cos(124sin14sin1424cos o00ooo

)AAcos(1IsinIsinIIcoscos CDDCCD

cos b = 0.9356

b = 20.67o

= 0.3608 radians

The Dogleg Angle, b, is given by:




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RFAsinIsinAsinIsin2

MDEast DDCC =

0110.180sin24sin20sin14sin2

400 oooo

ft x 98=D

ft 98011.1*66.96 ==



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RFAcosIsinAcosIsin2

MDNorth DDCC =

ft y 60=D

ft 60011.1*59.59 ==

0110.180cos24sin20cos14sin2

400 oooo



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RFIcosIcos2

MDVert CD =

0110.114cos24cos2

400 oo

ft z 381=D

ft 3810110.1*77.376 ==



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• At Point D,

• x = 1,000 + 98 = 1,098 ft

• y = 1,000 + 60 = 1,060 ft

• z = 3,500 + 381 = 3,881 ft



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The Radius of Curvature Method

2

CDCD

CDDC 180

)AA()II(

)AsinA(sin)IcosI(cosMDNorth

p

=

2180

)2080)(1424(

)20sin80)(sin24cos400(cos14

p

=

ft80y =D



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p

=

180

II

)IsinI(sinMDVert

CD

CD

ft783z =D

p

=

180

1424

)14sin24(sin400 oo



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• At Point D,

• x = 1,000 + 95 = 1,095 ft

• y = 1,000 + 80 = 1,080 ft

• z = 3,500 + 378 = 3,878 ft



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The Tangential Method

ft400MDD,toCfromdepthMeasured =

80 A 24I

20 A 14I

DD

CC

=

=

80sinsin24400=

DD AsinIsinMDEast D

ft160x =D



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24cos400=

ft365z =D

ft28=D y

oo 80cos24sin400



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Summary of Results (to the nearest ft)

• x y z

• Average Angle 1,100 1,084 3,878• Balanced Tangential 1,097 1,060 3,877• Minimum Curvature 1,098 1,060 3,881• Radius of Curvature 1,095 1,080 3,878• Tangential Method 1,160 1,028 3,865

Q i



Question

Plan a build and hold trajectory where thekick-off depth is at 2000’, and thetarget bull’s-eye is 5500’ from thesurface location at a TVD of 8100’. Usea build-up rate of 2 deg/100’. Your planshould include maximum inclination

angle, measured depth to the end of thebuild and to the target depth andhorizontal departure to the end of the

07 directional drilling

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