byTommy Warren

AMOCO Expl. & Prod. Technology Group

Rotary SteerableDirectional Drilling Systems:

The Way of the Future

Why Drill Directionally?

Production Enhancement

Offshore Development Environmental Sensitivity

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)

Drilling With Steerable Motor

Mud Motor

Stabilizer

BentHousing

Bit

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

Entire String Does NotMove Uniformly

Drill StringFriction

Normal Force

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

Sliding Inhibits Hole Cleaning

Drill String

Drill StringSliding

Rotating

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

Types of Rotary Steerable Systems

Bit Tilt without Side Force

Direct Side Force

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

Signal Port

e R = L2 / 2e

Blades

FlexibleJoint

EccentricSleeve

L

Mechanical RS Tool

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.