Copyright of Shell Exploration & Production Business Value of Stick-Slip Mitigation: Rejuvenation of Soft Torque Technology Mark Dykstra Rob Grauwmans July 2010 1 IADC Stick-Slip Mitigation Workshop Shell Projects & Technology Drilling Efficiency Optimization
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Copyright of Shell Exploration & Production
Business Value of Stick-Slip Mitigation: Rejuvenation of Soft Torque Technology
Mitigation of Stick-Slip using Soft Torque Rotary Systems
STRS description
Historic issues and recent improvements
Business Value: Case studies
Summary
July 2010 2IADC Stick-Slip Mitigation Workshop
Copyright of Shell Exploration & Production
Recap: The Science of Stick-Slip Conclusions
Torsional drillstring behavior includes torsional oscillations and stick-slip (periodic bit stalls)
Stick-slip is detrimental to drill bits and can be damaging to MWD tools
Stick-slip is relatively well understood, can be modeled, and can be recognized downhole and on surface
Stick-slip can be mitigated manually, automatically, and via downhole subs
Removing torsional oscillations increases the likelihood of MWD failure due to lateral vibrations
July 2010 3IADC Stick-Slip Mitigation Workshop
200 250
600
400
200
0
0
10
20
30
50
100
150
kN.m
kN
RPM
Reverse Rotation
Very High Bit RPM
Low WOB
Severe Torque Cycles
Stick-slippresent
Stick-slipNOT present
Copyright of Shell Exploration & Production
Economic Implications
High RPM accelerates wear
Reverse rotation and high RPM cause chipping and breakage
Blunt cutters drill poorly!
July 2010 4IADC Stick-Slip Mitigation Workshop
FootageTimeTripTimeDrillingRateRigCostBit
FootCost )(
Fewer bit runs
Longer bit runs
Faster bit runs Fewer trips
wfc TFvf
dtdH ,,
Wear rate RPM WOB Temperature
Abrasive Wear
Impact Damage
Glowka, D.: “Implications of Thermal Wear Phenomena for PDC Bit Design and Operation,” SPE 14222
Lower spread rate
Copyright of Shell Exploration & Production
Drilling Efficiency: New Versus Dull
The key to efficient drilling is to keep bits as sharp as possible, as long as possible
Both abrasive wear and impact damage must be controlled
Mitigating stick-slip is critical
July 2010 5IADC Stick-Slip Mitigation Workshop
J.V. Kenner, R. Waughman and T. Windham, “Alliance Yields New Understanding of Bit Wear - Drilling Performance Relationship,” ETCE98-4545, 1998 ASME Energy Sources Technology Conference & Exhibition
5
T1 Dull
New T1 Dull
New
Carthage Marble
Presenter
Presentation Notes
New vs. Dull: PDC Example The data shown in the right figures are for the light set PDC bit shown in the left photo drilling Carthage marble, which has a confined compressive strength of approximately 25 ksi. The solid black line represents the bit in new condition. As WOB increases the cutting mode transitions from grinding to shearing and the slope of the ROP versus WOB line increases as the MSE decreases. The peak efficiency at 20 klb is approximately 30%. Unlike the mill tooth bit in shale, The T1 dull condition required significantly more WOB – nearly twice as much -- for a given ROP in this hard rock. Accordingly, the MSE at a given WOB has also doubled. Further dulling would cause the slope of the ROP versus WOB to continue to decrease, as projected in the lighter dotted line.
Increased ROP by 10%July 2010 11IADC Stick-Slip Mitigation Workshop
STR
S O
FFS
TRS
ON
Detailed time zoom:Downhole stick-slip measurement:
Step change in stick-slip severity
Copyright of Shell Exploration & Production
Hans Deul Record Run
Well K15-FK-106, 12¼'' section drilled in 1 bit run from 1466 m to 5001m AHRT
Steering required at beginning (42º-55º) and end (55º-50º)
High WOB used in Rogenstein (30 MT vs. 22MT), lower RPM to reduce shocks due to whirl
STRS prevented onset of stick-slip at lower speed140 rpm
Average ROP = 30.2 m/hr
11.8 days ahead of base plan, 21.9 days ahead of AFE50/50
Saved millions of €July 2010 12IADC Stick-Slip Mitigation Workshop
Presenter
Presentation Notes
Additional points: First ever shoe to shoe run over this range of formations Rogenstein often drilled with impreg Keys for the success: give modern PDC bits and cutters good drilling conditions STRS keeps bit in shape PDC cutters survive hard/abrasive sands Rotary steerable BHA -> little (but some) BHA whirl
Copyright of Shell Exploration & Production
Results: Roger Lewis
Offshore Qatar
Batch drilling 8 ½” sections for >2 yr
Electroproject STRS installed for NP2-7, NP2-3 was previous best
42% ROP improvement since STRS
Keeping bits sharper, longer
July 2010 13IADC Stick-Slip Mitigation Workshop
No STRS With STRS0 100 200 300 400 500
11.5
12
12.5
13
13.5
14
MD
[100
0 *
ft]
ROP [ft/hr]
NP2-7 (With STRS)NP2-3
Copyright of Shell Exploration & Production
Results: Nabors F34
Northwest Louisiana
12 ¼” section, PDC, very hard rock (Hosston/Travis Peak)
Canrig STRS
Previous best performance with down hole motors
F34 drilled with rotary
STRS eliminates stick-slip
STRS + rotary matches performance with motor
Reduces spread rate
July 2010 14IADC Stick-Slip Mitigation Workshop
0 100 200
8300
8350
8400
8450
8500
8550
8600
ROP [ft / hr]
MD
[ft]
0 10 20
8300
8350
8400
8450
8500
8550
8600
TQ [k ft*lb]0 100 200
8300
8350
8400
8450
8500
8550
8600
SS [%]
Comparison Magnolia F34 vs. F20
0 50 100
8300
8350
8400
8450
8500
8550
8600
RPM0 50
8300
8350
8400
8450
8500
8550
8600
WOB [k*lbs]
F20. Motor. No STRS F34. ROTARY. CANRIG STRS
Copyright of Shell Exploration & Production
Summary
Stick-Slip is Expensive
Increased bit cost due to number of runs, repair/replacement charges
Increased hourly cost due to motor usage
Increased drilling time due to accelerated dulling (low ROP)
Increased trip time due to number of runs
Increased costs associated with downhole tool damage (MWD, LWD)
Mitigation of Stick-Slip using STRS Saves Money
STRS effective when properly implemented and commissioned
Proven ROP increases from 10-70%
Improved steerable system performance (reduced failures)