Rotary Steerable Systems
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Transcript of Rotary Steerable Systems
byTommy Warren
AMOCO Expl. & Prod. Technology Group
Rotary SteerableDirectional Drilling Systems:
The Way of the Future
Directional DrillingTechnology Evolution
Mud Motor &Bent Sub
1960 1970 1980 1990
WirelineSteering Tool
MWD
SteerableMotor
2000
Rotary SteerableSystems
0
10000
20000
30000
40000
1945 1955 1965 1975 1985 1995
Y ear
Cu
m.
Dir
. W
ells
Gulf of Mexico Directional Wells
1200 wells / year
After Stolle
Amoco Incentive for More Efficient Directional System
• Amoco spends $600 - 700MM per year drilling new wells
• 12- 15% of the wells directional but they use 35-40% ofdrilling budget
• 500,000 ft drilled with steerable motors, cost $60MM (excluding Canada and recompletions)
Steerable MotorsChanging Trajectory (Sliding)
• Drill-string Rotation Stopped
• Bit pointed in desired direction
• Interval drilled without drill-string rotation
Straight Sections (Rotating)
• Drill-string rotated continuously
• Stabilization may provide inclination
“Sliding” “Rotating”
control
Steerable Motor Directional System
Accepted PracticesCompromised well plan
Non-optimal bit selection
Reaming doglegs
Circulating and short tripping
Adding lubricants to mud
65% timeRotating
35% timeSliding
Steerable Motor Directional System
Rotating
Common ProblemsSliding DifficultyMaintaining orientationPoor hole cleaningLimited bit selectionLow effective ROPHigh tortuosityBuild rate formation sensitiveECD fluctuationsDifferential StickingBuckling and lock up
65% timeRotating
35% timeSliding
Common ProblemsVibrations Motor failures MWD FailuresAccelerated Bit WearPoor hole quality for logsPoor performance in air
Steerable Motor Directional System
65% timeRotating
35% timeSliding
Sliding ROP < Rotating ROP4100
4300
4500
4700
4900
5100
0 20 40 60 80 100 120 140
Penetration Rate, ft/h r
Dep
th, f
t
SlidingRotating
RotatingSliding
6000 7000 8000 9000
Depth, mBRT
0
4
8
12
16
Pen
etra
tion
Rat
e, m
/hr
20
Sliding May Become ImpracticalIn Some Wells
after Cocking, et al
7.00 hr - Drill, rotating and sliding to 12350 Attempted to slide 20 ft @ 12,316, Experienced wt. stacking problems. Got only 3 ft slide.
8.50 hr - Cont’d drill to 12,626. Experiencing much difficulty sliding. Unable to counteract assembly build rate of approximately 1o/100’. Cannot tolerate further build.
1.50 hr - Circ and prepare for trip. (18.5 hrs on bit.)
7.50 hr - POOH to change bit. PDC to roller cone. At report time pulling assembly.
On Bottom: Pick-up 400 klbs, Slack-off 260 klbs Torque 20 - 24 kft-lb (Average Daily cost $62,500)
Excerpt from Mornin g Report
6-1/2” hole PDC bit 456 M into horizontal hole
“4769 - 4770m Rotate. 4770 - 4774 Orient 0. String sticking. 4774-4775 Rotate. 4775-4776 Orient 0. String sticking. Work stringconstantly while orienting. Pipe sticking off bottom. Unable to applyWOB. Unable to stay on bottom long enough to generate tool face.Progress made by rotating and spudding bit without tool face.Impossible to steer any more in this hole section.”
Spotted Cement plug and re-drilled horizontal section.
Excerpt from Morning Report
System Interactions Cause Sliding Difficulty
• Drill-string friction
• Motor torque output
• Bit Torque/WOB relationship
Example
Peak Drag = 67,000 lb
Drag after breakback = 50,000 lb
Minimum WOB Increment = 17,000 lb
Minimum Sliding WOB Increment
Dra
g F
orce
Time
Dynamic Friction
Static Friction
25%
Drill String
Drag
0
1000
2000
3000
4000
5000
0 10 20 30 40
Weight-on-Bit, 1000 lb
Tor
que,
ft-lb
Larger WOB Operating Windowfor Roller Cone Bits than PDC Bits
Differential Pressure
RP
M
& T
orqu
e
Torque
Full LoadRated Pressure
Speed
Roller Cone
PD
C
Penetration Rate forPDC bit would bemuch higher than forroller cone bit
Differential Pressure
RP
M
& T
orqu
e
Torque
Full LoadRated Pressure
Speed
0
50
100
150
200
0 10 20 30 40
W eigh t-on-B it, 1000 lb
RO
P,
ft/h
r
0
1000
2000
3000
4000
5000
0 10 20 30 40
To
rqu
e,
ft-l
b
Roller Cone
PD
C
• Directional Driller always picks bit for steerable motor that allows him to slide, otherwise there would be no need to run the steerable motor.
• The overall result is that the best bit for the motor is selected rather than the best bit for the formation.
Bit Constraints Limit Performance for Both Rotating and Sliding
Problem with drilling straightwith “bent” motor
Bit and Hole Axis AlignedBit Axis Tilted relative
to Hole Axis
Rotating
Not allcutters touchthe rock.Sliding
Ledges
Aggressive Build Rate
• Reduces amount of sliding
• But increases tortuosity
Survey Station
Survey Station
DLS = 4o /100 ft
DLS = 16o/100 ft
Slides
DLS = 16o /100 ft
DLS =
16o /1
00 ft
Rotating/Sliding Produces Tortuous Hole
SteerSteerSteer Drill
Drill
12:00 14:00 16:00 18:00 20:00 22:00 24:00
Time, hrs
13.99
13.83
13.66
13.49
13.33
13.16
PW
D E
MW
, ppg
Poor Hole Cleaning While Steering
SOBM 12-1/4” Section
StringRotation
Pres. WhileDrilling
Cuttings
Curtsey Sperry-Sun
• We routinely accept inefficient practices as a necessary cost of drilling directional wells!
• We design wells to accommodate steerable motor limitations.
• Understanding the fundamental cause of directional drilling inefficiencies points to developing a new directional drilling method.
Bottom Line
• Provides continuous pipe rotation while drilling
• Does not require a mud motor
• Bit steered by mechanism immediately above bit
• May use automated orientation or may be manually oriented like a motor
Rotary SteerableDirectional Drilling Systems
Bit Side Force Trajectory
ActuatorDeviationDirection
StaticControlValve
Static Bit Force(BHI Autotrak)
Dynamic Bit Force(Camco SRD)
Non-rotatingSleeve
Rotating
Shaft
High Side
DeviationDirection
Rotating Housing
Automated Bit Tilt Systems
Deflected Drive Shaft (CDA)
Contra-Nutating System (3D)
Non-Rotating Housing
Rotating Housing
Angulation Joint
Shaft Deflector
Top End Shaft Orienter
Rotary Steerable System Benefits• Reduces axial stick/slip problems• Better hole cleaning and lower ECD when pipe is rotated• Smoother holes, less reaming required• More controllable build rates• May use better bit for formation• Better bit life• Can place sensors closer to the bit
Wytch Farm Extended Reach Wells
6 km
8 km
10 km
Poole Harbor
TD LocatorsWell Sites
M11M05
M09
M03
M02
1000
20009-5/8” 7”
1098765432113-3/8”0
TV
D, m
M11 Trajectory
Lateral Displacement, KM
Camco RS
2 2
1 0
7 .5
1 2
6
1 0 .9
0
5
1 0
1 5
2 0
2 5
E ffectiveR O P
N o . o fT r ips
N o . o fda ys
AutoTrak Case Histor y - Norwa y
4 last offsetsAutoTrak
Deutag Rotar y Steerable S ystem900
925
950
975
1000
1025
0 100 200 300Displacement, m
True
Ver
tical
Dep
th, m 40 m rad.
132 ft rad.
18 ft Target0.8o dip
Argentina Well Total elapsed time : 4-1/2 days
-300
-200
-100
0
0 100 200 300E ast, m
Sout
h, m
TargetAz. 110o
• They can reduce the cost of wells we currently drill by improving the efficiency of the directional drilling process.
• They enable things we could not otherwise do, ie longer reach wells and more complex well paths with reduced risk.
Why Rotary Steerable DirectionalSystems Will Take Over
System Selection
ReliabilityCapabilityAvailability
Cost
SystemA
SystemB
• Anadrill• Baker Hughes INTEQ• Camco• Camb. Drl. Automation
• Deutag / IDR• Dir. Drilling Dynamics (3D)• 3D Stabilizers
• Maersk • Sperry Sun • Tucker Energy• Others
Rotary Steerable Market Expansion
Conventional Steerable Motor Directional and Horizontal
Drilling Market
19992000
20012002
2003
RS Marke
t Growth
Current Rotary Steerable Market
New Market
Summary
• Steerable motor systems introduce many inefficiencies into a drilling operation which are accepted as cost of doing business.
Summary
• Steerable motor systems introduce many inefficiencies into a drilling operation which are accepted as cost of doing business.
• Rotary Steerable systems potentially are much more efficient, and may take over most of the directional market within the next few years.
Summary
• Steerable motor systems introduce many inefficiencies into a drilling operation which are accepted as cost of doing business.
• Rotary Steerable systems potentially are much more efficient, and may take over most of the directional market within the next few years.
• Systems under development are aimed at both the high tech and low tech ends of the market.