1. Petroleum Engineering 411 Well Drilling
Lesson 28
SMD Well Control

2. Subsea Mudlift Drilling ( SMD ) Note Pump and ReturnLine

3. DESIGN PROJECT
Your PETE 411 Design Project is Due in Dr. J-W’s Office by 5 p.m. on Monday, Dec. 9, Monday, Dec. 2 is set aside for you to get together with your team mates to work on the project during regular class hours.

4. Contents - Review of Conventional Well Control Kick Detection in SMD
Kick containment in SMD
Behavior of Real Gases in SMD Wells
Well Control in SMD

5. Kick Detection & Well Control - Review - Conventional -
Kick Indication (what is a KICK?)
Kick Detection (confirmation)
Kick Containment (stop flow into well)
Circulate Kick out of hole
Increase Mud Weight in hole (if necessary)

6. Circulate Kick out of hole
Conventional Wait and Weight Method
Old Mud
Kick
Kill Mud
BHP = Constant
Keep the BHP constant throughout

7. Gas Kick Behavior - Perfect Gas
Maximum Choke Pressure = 1,000 psia. BHP = 6,000 psia
0.02 deg F/ft
0.00 deg F/ft
0.01 deg F/ft 23

8. Z-Factor - In Shallow Wells
Gas Specific Gravity = (S.G. of air = 1) 23

9. Shallow Gas Kick - Summary
0.02 deg F/ft
Real Gas
Ideal Gas
PV = constant 23

10. Gas Kicks in Deep SMD Wells
MudLine
MudLift
Pump
As expected, most of the expansion occurs in the top 3,000 ft or so 23

11. Gas Kicks in Deep SMD Wells
PV = ZnRT
PV = constant 23

12. Gas Kick Behavior - Z-Factor
Gas Specific Gravity = (S.G. of air = 1)
3.0 30 60
pV=ZnRT
100
150
2.5
200
300
400
2.0
Compressibility (Z-Factor)
Temperature, o F
1.5
1.0
0.5
5,000
10,000
15,000
20,000
25,000
Pressure, psig 23

13. ~SEAWATER HYDROSTATIC PRESSURE
Subsea Mudlift Drilling System
FLOATER
Surface Pump: Constant Rate
Mudlift: Const. Inlet Press.
~SEAWATER HYDROSTATIC PRESSURE
10,000’
SEAFLOOR
BOP
MUDLIFT
30,000’
KICK
What next?? 27

14. Kick Detection and Control28

15. Kick Detection and Control
Influx has stopped and
pressures have stabilized
ATM 28

16. Kick Detection and Control
ATM 28

17. 29

18. SICP
CONVENTIONAL 30

19. 31

20. 32

21. Kick Detection Method Still Valid for SMD?
Pit Gain Still valid
Flow Rate Increase (Returns) Much Better
Well Flows With Rig Pump Off … U-tubing ...
Fluid Fill-up on Trips … More complicated
Increased Hook Load Still Valid
Drop in Standpipe Pressure Better
Drop in BHP - MWD Still Valid
Drilling Break Still valid
Decreased Mud Weight (Gas Cut) Still valid 33

22. Well Control Summary
Most Conventional kick detection methods are still valid
New differential flow rate method - better - use with computer monitoring
Lower standpipe pressure makes kick detection easier and faster
Conventional well control can be adapted with modifications 34

23. Well Control Summary cont’d
Not necessary to shut well in …
Seafloor pump controls the BHP
Surface choke pressure generally does not affect wellbore pressures
Well control training will be essential !! 35

24. General Summary
Subsea Mudlift Drilling is a method that offers potential for lowering drilling costs in very deep waters.
( fewer casing strings, smaller rigs, less time on location, larger hole )
The method utilizes one or more small-diameter return lines from the seafloor to the surface. The drillpipe is not inside a return line. 36

25. Summary - cont’d
A “mudlift” system is used in the return line thereby making a “dual-density” mud system possible.
Wellhead pressure is maintained at seawater hydrostatic, so well is “dead” at all times
Well control is quite similar to that in conventional drilling with a riser There are some real advantages:
higher margins, choke line DP, etc. 37

26. ATM
THE END 38

27. ~SEAWATER HYDROSTATIC PRESSURE
U-Tubing in SMD
ATM
FLOATER
~SEAWATER HYDROSTATIC PRESSURE
STATIC FLUID LEVEL
BOP
MUDLIFT 23

28. ANNULUS AND RETURN LINE SEA WATER HYDROSTATIC PRESSURE
Static Pressures - SMD
ANNULUS AND RETURN LINE
DRILLSTRING PRESSURE
SEAFLOOR
DEPTH
SEA WATER HYDROSTATIC PRESSURE
PRESSURE 18