Improved weight on bit

Geologic

Weight Bit Sensor

Geologic

Drilling geologically maximizes drain hole exposure to the reservoir.

GeoSteering Tool

The GeoSteering* tool incorporates drilling and evaluation measurements into a standard Schlumberger mud-lubricated steerable motor. The GeoSteering tool provides the directional driller real-time, near-bit measurements to keep the wellbore within the reservoir. The results are maximum pay zone footage, improved production per foot drilled and lower completion costs.

The primary components of the GeoSteering tool include the reliable PowerPak steerable motor and an instrumented motor housing which contains gamma ray, resistivity and inclination sensors. A wireless telemetry system elec-tromagnetically transmits drilling and evaluation data to the measurement while drilling (MWD) system above.

The motor specifications include an instrumented fixed bend housing integrated between the motor bearing section and the surface-adjustable bent housing. The fixed bend is located at a distance of 5 ft from the bit face and is currently available in angles of 0.75, 1.25, and 1.5 degrees.

The near-bit measurement sub located above the fixed bent housing contains the measurement sensors. The various sensors provide a laterolog bit resistivity, azimuthal electrode resistivity, azimuthal gamma ray, inclination, toolface and motor revolutions per minute (RPM). The near-bit measurements are made at a distance from 2.5 ft to 8 ft from the actual rock being drilled.

With each start-up of the pumping cycle, complimentary survey data (inclination, gravity tool face, total gravitational field, and battery voltage) is transmitted to the MWD tool to be pulsed to surface. The tool then automatically enters drilling mode where it transmits bit and azimuthal resistivity, azimuthal gamma ray and RPM data. The laterolog bit resistivity measurement is capable of operating in all types of mud whereas the azimuthal resistivity is accurate only in conductive environments. Unlike 2-MHz resistivity measurements at high angle, geosteering resistivities are relatively insensitive to anisotropy which simplifies steering decisions.

The GeoSteering tool offers formation logging capability in an azimuthal referencing mode. Measurement sensors are oriented with respect to tool face to provide up/down resistivity and gamma ray data for geosteer-ing purposes. The near-bit inclination measurement enhances trajectory control by providing immediate information about bit direction and BHA tendency. These features make the GeoSteering tool the one of choice on world-record breaking extended reach projects and challenging wells with trajectories within a few feet of an oil-water contact.

On surface, a real-time GeoSteering Screen enables the drilling team to determine the location of the bit in the reservoir by comparing real-time geological measurements made at the bit with the reservoir model. Reservoir data is modeled on the INFORM* Integrated Formation Modeling package to help interpret complicated formations such as faults, folds, domes, etc. The real-time data can be plotted and analyzed at the wellsite and transmitted to client offices around the world.

The GeoSteering tool incorporates drilling and evaluation measurements into a standard Schlumberger mud-lubricated, steerable motor.

Steerable Motor
Inlcination, RPM

GeoSteering Tool Specifications

Measurement Performance Specifications

General Specifications

Bit Inclination

Nominal diameter

63/4 in.

Range

0 to 125°

Maximum diameter

7/2 in.

Accuracy

±0.2 at 2 sigma

Total length

30.4 ft (4:5 motor)

Distance from bit box

8.6 ft

Hole size

83/8 in. to 97/8 in.

Maximum external Pressure

15,000 psi

Tool Face

Maximum temperature

302° F (150° C )

Range

-180 to 180

Accuracy (at 2 sigma)

±2.0° at 5° inclination ±1.0° at 10° inclination

Mechanical Specifications

Bent Housing and Stabilizer

±0.5° at 20° inclination

Lower fixed bent-housing

0.75°, 1.25°, or 1.5°

Upper surface adjust. bent-housing

0° to 3°

RPM Measurement

Range Accuracy

0 to 512 rpm ±1 rpm

Dogleg Severity

Rotary mode

Bit offset less than 2.2 in.

Sliding mode

16°/100 ft

Gamma Ray Measurement

Scintillation 0 to 250 API

Connections

Range

Sensitivity

Upper connection

41/2 in. Reg, HC-50, XH, or H90

1 cps - 4.5 API units

Lower (bit box)

4/2 in. Reg or 65/8 in. Reg

Accuracy

10%

Resolution

5% for 100 API at 100 ft/hr

Axial Load

Delta Pressure Across Bit

Distance from bit box

7.9 ft

500 psi 1000 psi

1500 psi

Recommended WOB

15,000 lbf 21,500 lbf

28,000 lbf

Bit Resistivity in Water-Base Muds

Maximum WOB Maximum pull (back ream) Working over-pull Absolute over-pull

65,000 lbf 71,500 lbf 35,000 lbf 28,500 lbf 75,000 lbf 255,000 lbf

78,000 lbf 22,000 lbf

Range Accuracy

Vertical resolution

0.2 to 2000 ohm-m ±5% for resistivity < 200 ohm-m ±10% for resistivity > 200 ohm-m Typically 4.5 ft

Drilling Performance Parameters

4/5 section (4.8 or 7 stages)

7/8 section (3 stages)

Depth of investigation Distance from bit box

Typically 2.0 ft

Flow rate Bit speed Torque

300 to 500 gpm 105 to 210 rpm 3,360 ft-lbf

300 to 600 gpm 62 to 118 rpm 3,830 ft-lbf

Azimuthal Resistivity in Water-Base Muds

Range 0.2 to 200 ohm-m

Pressure drop

691 psi

488 psi

Accuracy

±10%

Vertical resolution

Typically 4 in.

Depth of investigation

12 in.

Distance from bit box

4.0 ft

GeoSteering Tool Specifications

General Specifications

Nominal diameter

8.31 in.

Maximum diameter

9/2 in.

Total length

26 ft (4:B motor)

Hole size

10% in. to 16% in.

Maximum external Pressure

18,000 psi

Maximum temperature

302° F (1B0° C )

Mechanical Specifications

Bent Housing and Stabilizer

Lower fixed bent-housing

0.7B°, 1.2B°, or 1.B°

Upper surface adjust. bent-housing

0° to 3°

Dogleg Severity

Rotary mode

Bit offset less than 2.2 in.

Sliding mode

16°/100 ft

Connections

Upper connection

6% in. Reg Box

Lower (bit box)

6% in. Reg Box

Axial Load

Measurement Performance Specifications Bit Inclination

Range Accuracy

Distance from bit face

Tool Face

Range Accuracy (at 2 sigma)

-180 to 180 ±2.0° at inclination ±1.0° at 10° inclination ±05° at 20° inclination

Gamma Ray Measurement

Detector type

Range

Sensitivity

Accuracy

Resolution

Distance from bit box

Scintillation

0 to 2B0 API

for 100 API at 100 ft/hr

Bit Resistivity in Water-Base Muds

Range Accuracy

0.2 to 2000 ohm-m

Range Accuracy

0.2 to 2000 ohm-m

Maximum WOB without flow

6B,000 lbf

71,B00 lbf

78,000 lbf

±10% for resistivity > 200 ohm-m

Maximum WOB with flow

6B,000 lbf

71,B00 lbf

78,000 lbf

Vertical resolution

Typically 132 in.

Maximum jarring load

3B,000 lbf

28,B00 lbf

22,000 lbf

Depth of investigation

36 in.

Maximum torque (pin yield)

6B,000 lbf

71,B00 lbf

78,000 lbf

Distance from measurement

Maximum rotary torque

6B,000 lbf

71,B00 lbf

78,000 lbf

point to bit face

65 in. ft

Ring Resistivity in Water-Base Muds

Drilling Performance Parameters

Flow rate

Bit speed

Torque

Pressure drop

300 to 900 gpm

7B to 22B rpm

4100 ft-lbf

37B psi

7/8 section (3 stages)

300 to 900 gpm

48 to 14B rpm

4B00 ft-lbf

370 psi

7/8 section (4.0 stages)

300 to 900 gpm

48 to 14B rpm

9B00 ft-lbf

B0B psi

Ring Resistivity in Water-Base Muds

Range Accuracy

0.2 to 2000 ohm-m ±5% for resistivity <2000 ohm-m ±20% for resistivity between 2000 and 20,000 ohm-m

Features and Benefits

  • Continuous drillstring rotation while steering for reduced undulations
  • Directional control without reactive torque restrictions on toolface
  • Surface controlled directional programming for variable build/turn rates in real time
  • Superior hole cleaning due to rotation reduces the risk of stuck pipe
  • Variable WOB and rotary speed provide maximum ROP's while building/turning
  • Directional control with any bit type
  • Greater reach capabilities provide a means for fewer wells and fewer platforms

PowerDrive Rotary Steerable System

The Schlumberger PowerDrive tool provides three-dimensional control of wellbore deviation while continually rotating the drillpipe. This unique tool uses mud actuated pads to deviate the direction of drilling by applying directed pressure against the rock as the drillstring is rotated. The tool can be run as a stand-alone unit or in combination with MWD and LWD tools with real-time communication to surface.

The PowerDrive rotary steerable technology addresses the challenges of extreme directional drilling conditions found in horizontal and extended-reach well designs. Torque, drag and hole cleaning issues limit standard drilling methods using steerable downhole motors. PowerDrive's capability to continuously rotate the drillstring while steering produces a faster, more controllable drilling system resulting in a smoother, cleaner, longer wellbore.

The PowerDrive design is a simple, reliable system contained in a short, 12'/2 ft (3.8 m) near-bit assembly that easily accommodates most MWD and LWD components. The tool is comprised of two principal components:

  • The Bias Unit - Applies a lateral force to the bit while rotating at bit speed.
  • The Control Unit - A roll-stabilized platform located within a nonmagnetic collar above the bias unit. It contains self-powered electronics and sensors that set the direction and magnitude of the force vector applied to the bit.

The bias unit is directly connected to the drill bit. Three exterior pads are kept in constant contact with the formation by internal, mud-powered actuators. A three-way disc valve controls the flow of mud and the associated pressure applied to the actuators. When deviation is required, each actuator is extended in sequence against the side of the hole opposite the intended bias direction. The pads are in constant contact with the wellbore, extending and retracting in a smooth, continuous motion, guiding the bit along the intended well path. When no deviation is required, the PowerDrive system is put in neutral mode by simply rotating the disc valve stator relative to the high side. This causes the pads to push in every direction and effectively cancel each other to allow the bit to continue on its trajectory.

The control unit is mechanically linked to the bias unit and sets the direction and deviation. Sensor and control electronics are contained within a cylindrical pressure housing mounted on bearings within the drill collar. The bearings allow the control unit to rotate or remain stationary, independent of drillstring rotation. Power is generated through two turbine impellers that support the control unit's sensors and electronics.

PowerDrive directional programming can be surface controlled during the drilling operation using a sequence of mud pulses. Two-way communication is available with the use of electromagnetic transmission between the Schlumberger MWD system and PowerDrive. The communication provides near-bit inclination and azimuth information in addition to confirmation that downlinked commands were properly received.

The advanced technology of PowerDrive rotary steerable services extends wellbore construction capabilities, lowers drilling cost, and increases productivity. Improved reach with improved control allow for more effective reservoir development. PowerDrive's agile inclination and azimuth control keep the bit in narrow pay zones and makes distant objectives a reality in extended-reach operations. As a result, reservoir coverage and drainage are improved while capital expenditures are reduced.

Bias Unit Sub

Control unit

Bias unit

Control unit

Bias unit

Pad out

Pad in

Pad out

Pad in

Schlumberger Bias UnitSchlumberger Powerdrive Rotational Check

PowerDrives rotating actuator provides directed pressure for precise directional control.

PowerDrive Specifications

General Specifications

PowerDrive675

PowerDrive900

Nominal diameter

6% in.

9 in.

Hole size

8/2 in., 8% in., 9/2 in., 97/8 in.,

121/4 in.

System operating prinicpal

Bias, "Push the bit"

Bias, "Push the bit"

Build up rate

0 to 8°/100 ft

0 to 8°/100 ft

Maximum pass through

Sliding

15°/100ft

12°/100ft

Rotating

8°/100ft

67100ft

Total Length

Without stabilizer

12.4 ft

15 ft

Total Weight

Without stabilizer

1716 lbm

2610 lbm

Power source

Turbine alternator

Turbine alternator

Mechanical Specification PowerDrive675 PowerDrive900

Axial Load

Maximum WOB

55,000 lbf

80,000 lbf

Maximum torque

30,000 lbf

50,000 lbf

Hydraulics

Flow rate

300 gpm to 650 gpm

500 gpm to 1000 gpm

Pressure rating

18,000 psi

18,000 psi

Maximum temperature

120°C

120°C

Max sand content

0.50%

0.50%

LCM content

50 lbm/bbl medium

50 lbm/bbl medium

Real time data link

Yes

Yes

Downlink

Mud flow variation

Mud flow variation

Closed loop programming

No (planned for Q1 2000)

No (planned for Q1 2000)

RPM range

40 to 220 rpm

40 to 220 rpm

Measurement Specifications

Measurement Specifications

At PowerPulse startup Inclination, Azimuth, Steering Setting,

Gravitational and Magnetic Field, Tool Status

Real time Inclination, Azimuth, Steering Setting

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