theory slides 2
DESCRIPTION
dress aidTRANSCRIPT
1
KICK WARNING SIGNSKICK WARNING SIGNS
2
WHAT IS A KICK WARNING SIGN?
A WARNING SIGN TELLS YOU:-
THE WELL MAY BE GOING
“UNDERBALANCED”
OR
YOUR SAFETY MARGIN IS GETTING LESS.
3
Formation Pressure 9.0ppg
Mud Weight 10.0 ppg
What is happening?Drilling normally pressured shaleOverbalance
Warning Signs
4
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
Warning SignsWhat is happening?As the formation pressure gets closer to the mud weight, we will observe changes in;
ROPHole conditionGas levelsCuttings propertiesMud properties
5
Warning Signs
GEOLOGRAPH CHART
IncreasingDrill Rate
(ROP)
9850’
9855’
9860’
9.00
9.15
9.30
Increased drilling rateMud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
6
Warning Signs
BIT
Increased drill string torque and drag
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
7
Warning SignsCuttings size & shape
Drilled cuttings
Cavings
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
8
Warning SignsFlowline temperature
NormalPressure
AbnormalPressure
Temperature Increase
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
9
Warning SignsShale density
NormalPressure
Increasing Formation Fluid
Pressure
Increasing Shale Density
9500’
9700’
9900’
10100’
9600’
9800’
10000’
10200’
Normal Trend Line
Shale
Shale
Shale
Sand
Sand
Sand
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
10
Warning SignsBackground & connection gas
5% 10%15%
1.002.003.004.005.006.00
Hours
1.002.003.004.005.006.00
Hours BACKGROUND GAS
CONNECTION GAS
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
11
Pressure Losses
Where does Pump Pressure come from??
12
Total Pump Pressure
PSI
= Surface Line friction
PSI
= Drillstring friction
PSI
= Bit (jet nozzle) friction
PSI
= Annulus friction
PSI
Total Pump Pressure
13
What Affects Pressure Loss
PSIPSI30 SPM 50 SPM
14
What Affects Pressure Loss
PSIPSI30 SPM 30 SPM
10 ppg 15 ppg
15
What Affects Pressure Loss
PSIPSI
Low Vis. High Vis.
16
What Affects Pressure Loss
PSIPSI50 SPM 50 SPM
Large nozzle Smell nozzle
17
What Affects Pressure Loss
PSIPSI
Hole size
18
Annulus Pressure Loss
30 SPMPSI
• Annulus pressure loss can be quite small.
• 50 -300 psi• This pressure acts on
hole wall and bottom• Increases with depth,
pump speed, hole size and pipe size.
19
Effect on Bottom Hole Pressure
90 SPMPSI
• If Annulus friction = 150 psi.• Mud Weight = 11 ppg• TVD = 8700 ft• What is the pressure on the
bottom of the hole?
= (11 x .052 x 8700) + 150
= 5126 psi
20
• Gas at choke line, wellbore
fluids as shown on drawing.
• Using APL = 75psi, calculate
the circulating BHP.
• What is about to happen to the
casing pressure?
Bottom Hole Circulating Pressure
800psi
667psi
600psi
RKB 0
1800 ft10.8 ppg
mud
2000 ft12.0 ppg kill mud
3500 ft 10.0 ppg
mud
Subsea BOP
CL FL 200psi
(dynamic)
APL75 psi
BHP 5000 psiPf = 5000 psi
RKB 2500
RKB 1800’
RKB 6000’
RKB 8000’
00
21
Bottom Hole Pressure
Static Dynamic
22
Connection Gas
PSI
3000 psi
BHP=7114 psi
11 ppgmud
Formation Pressure = 7000 psi12000’
AnnulusPressure Loss
= 250 psi
Mud CirculatingFormation Under Control
23
Connection Gas
BHP=6864 psi
Formation Pressure = 7000 psi12000’
Circulation StoppedFormation Not Under Control
PSI
AnnulusPressure Loss
= 0 psi
11 ppgmud
24
Connection Gas
PSI
3000 psi
BHP=7114 psi
Formation Pressure = 7000 psi
AnnulusPressure Loss
= 250 psi
Mud CirculatingFormation Under Control
25
Connection GasPSI
3000 psi
BHP=7114 psi
Formation Pressure = 7000 psi
AnnulusPressure Loss
= 250 psi Action to take•Increase mud weight.
•Control drilling.
•Minimize the connection time.
26
Warning SignsBackground & connection gas
5% 10%15%
1.002.003.004.005.006.00
Hours
1.002.003.004.005.006.00
Hours BACKGROUND GAS
CONNECTION GAS
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
27
Warning SignsWarning signsTell you overbalance
Major warning signs are:• Increasing ROP• Increasing torque/drag• Increased quantity/size of cuttings• Increased background gas• Connection gas• Increasing temperature• Decreasing shale density
What if we ignore them?
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
28
Warning SignsWhat is happening?• The formation pressure
is increasing and may lead to Underbalance
What will happen?
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
Formation Pressure 10.1ppg
29
Warning Signs
• Underbalance
• Permeable formation
Kick
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
Formation Pressure 10.1ppg
30
Warning SignsWhat happens?• Underbalance• Stuck• As shale has very low
permeability, the well cannot flow so the hole will collapse and we will get stuck.
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
Formation Pressure 10.1ppg
31
Warning SignsWarning signsTell you overbalance
Major warning signs are:• Increasing ROP• Increasing torque/drag• Increased quantity/size of cuttings• Increased background gas• Connection gas• Increasing chlorides• Increasing temperature• Decreasing shale density
What should we do?
Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
32
Warning Signs
What should we do?Mud Weight 10.0 ppg
Formation Pressure 10.0ppg
Formation Pressure 9.0ppg
Pressure
and
Porosity
Increasing
Flow Check
Circulate Bottoms Up
Raise Mud Weight
33
KICK INDICATORSKICK INDICATORS
34
PADDLE
GAUGEon
Driller’sConsole
Kick Indicators
35
PADDLE
GAUGEon
Driller’sConsole
Kick Indicators
36
Kick Indicators
GAUGEon
Driller’sConsole
37
GAUGEon
Driller’sConsole
Kick Indicators
38
Trip Tank
TRIP TANKPUMP
Normal Drop in LevelTrip
Tan
k Le
vel
Stands Pulled
Drop in Trip Tank Level
39
Kick Indicators
What are the indicators that the well is flowing?
• Increase in Flow Rate
• Increase in Pit Level
• Drop in pump pressure withan increase in spm
What Action Should Be Taken?
Check to see if well is flowing with the pump off.
40
KICK DETECTION IN OIL BASE MUD
•OIL AND GAS ARE HYDROCARBONS.
•GAS IS SOLUBLE IN OIL BASE MUD.
•GAS IS NOT SOLUBLE IN WATER BASE MUD.
•GAS IN SOLUTION DOES NOT EXPAND UNTIL NEAR SURFACE.
DRILLER WILL SEE PIT GAIN IN WBM EASIER
THAN OBM WITH THE SAME KICK SIZE.
41
KICK DETECTION IN OIL BASE MUD
42
Top hole drilling
43
The diverter system includes:
• Diverter - a low pressure annular preventer used to seal the wellbore from the flowline.
• Vent lines - large diameter piping used to flow the fluids downwind of the rig (port and starboard).
• Vent line valves - full opening valves used to select and isolate the desired vent line.
• Hydraulic control system - functions the diverter and automatically opens the selected vent line valve. Drive Pipe or
Conductor casingVent lines
FlowlineBell Nipple
Vent line Valves
Diverter
Large diameter drive or conductor pipe is usually installed below the mud line for spudding in an offshore location and a casing string is set and cemented at shallow depth for land locations. This pipe provides a seal capable of supporting the hydrostatic of the mud column from the base of the casing to the flow nipple outlet. The diverter system is installed on the drive or conductor casing.
The working pressure of the diverter and vent lines is not of prime importance, rather they are sized to permit high flow rate diversion of wellbore fluids while minimizing wellbore back pressure.
44Shallow Gas Blowout in the Gulf of Mexico
45
Problems• Shallow gas
– Can cause loss of rig due to explosion or capsizing.• Weak Formation• Losing the hole
– Might require re-spudding in a slightly different location
• Charged Formations
• Is it series problem???
Top hole drilling
46
SHALLOW GAS INCEDENT
47
SHALLOW GAS INCEDENT
48
49
What will happen as the formation is penetrated?
Shallow Gas
50
Shallow Gas
51
52
53
Top hole kick prevention• Drill pilot hole• Be careful when hole opening• Control drilling• Keep hole clean• Keep mud weights low to prevent losses• Pump out of hole
Shallow gas
54
Shut in procedures
55
Lined up with remote choke closed
Pick upShut down pumpsCheck flow - if flowing;
1-Close BOP2-Open HCR (hydraulic stack
valve)3. Record pressure
Hard shut in while drilling
56
Lined up with remote choke openPick upShut down pumpsCheck flow - if flowing;
1. Open HCR 2. Close BOP*3. Close remote choke4. Record pressure
Soft shut in while drilling
57
What is different?– String is open
• Valves and crossover required
• Safety valves– Full opening safety valve– Non return valve
Kicks while tripping
58
Full opening safety valve
TIW SMF
Kelly cock
59
Non return valve
Gray valveIBOP
60
Lined up with remote choke closed1. Install FOSV2. Close FOSV3. Close BOP*3. Open HCR6. Record pressure
Hard shut in while tripping
61
Lined up with remote choke open
1. Install FOSV2. Close FOSV3. Open HCR4. Close BOP*5. Close remote choke 6. Record pressure* API soft shut in states BOP (either Ram or Annular )
Soft shut in while tripping
62
Should only be considered on top hole where formation is weak.
1. Stop drilling (keep pumping)2. Activate Diverter With One Button- this will:
- Open vent line- Close flowline/shaker valve- Close diverter
3. Increase pump speed to maximum4. Pump mud 5. If well is still flowing after mud is pumped, line up and
pump water.
Diverting
63
SHUT IN PRACTICES
THINGS THAT DELAY SHUT IN.
• FLOW/PIT ALARMS NOT SET OR WORKING
• DRILL TOO FAR AFTER DRILLING BREAK
• LACK OF ‘SHUT IN’ TRAINING
• LACK OF MAINTENANCE + TESTING
• WAITING FOR INSTRUCTIONS
• ACCUMULATOR UNIT NOT WORKING
• NOT MONITORING TRIPS