Three-dimensional steering tool for controlled downhole extended-reach directional drilling

• US 6,470,974 B1
• Filed: 04/13/2000
• Issued: 10/29/2002
• Est. Priority Date: 04/14/1999
• Status: Expired due to Term

• Current Assignee: WWT North America Holdings, Inc.
• Original Assignee: Western Oiltools Ltd.
• Inventors: Moore, N. Bruce, Beaufort, Ronald E., Krueger, R. Ernst
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): GAY, JENNIFER HAWKINS
• Application Number:
  US09/549,326
• Time in Patent Office: 929 Days
• Field of Search: 731/524.3, 731/524.5, 731/524.6, 731/525.1, 166/50, 166/65.1, 166/117.5, 166/153, 166/250.01, 166/255.1, 166/255.2, 175/26, 175/40, 175/45, 175/50, 175/73, 175/74, 175/320
• US Class Current: 175/45
• CPC Class Codes: E21B 23/08 Introducing or running tools by fluid pressure, e.g. through-the-flow-line tool systems
• CPC Class Codes: E21B 4/18 Anchoring or feeding in the borehole
• CPC Class Codes: E21B 44/005 Below-ground automatic control systems
• CPC Class Codes: E21B 7/062 the tool shaft rotating inside a non-rotating guide travelling with the shaft E21B7/067 and E21B7/068 take precedence
• CPC Class Codes: E21B 7/068 drilled by a down-hole drilling motor down-hole drives per se E21B4/00, E21B7/067 takes precedence

Abstract

A steering tool for extended-reach directional drilling in three dimensions comprises a mud pulse telemetry section, a rotary section, and a flex section assembled as an integrated system in series along the length of the tool. The flex section comprises a flexible drive shaft and a deflection actuator for applying hydraulic pressure along the length of the shaft for bending the shaft when making inclination angle adjustments during steering. The rotary section comprises a rotator housing coupled to the deflection housing for rotating the deflection housing for making azimuth angle adjustments during steering. The onboard mud pulse telemetry section receives inclination and azimuth angle steering commands together with actual inclination and azimuth angle feedback signals during steering for use in controlling operation of the flex section and rotary section for steering the tool along a desired course. The steering tool can change inclination and azimuth angles either simultaneously or incrementally while rotary drilling.

Claims

1. In a system for drilling a borehole in an underground formation, in which the system includes an elongated conduit extending from the surface through the borehole and a drill bit mounted at a forward end of the conduit for drilling the borehole through the formation, an improvement comprising a three-dimensional steering tool mounted on the conduit near the drill bit, the steering tool comprising an integrated telemetry section, rotary section and flex section aligned axially along the steering tool for separately controlling inclination angle and azimuth angle at the drill bit;

in which the flex section includes an elongated drive shaft coupled to the drill bit and adapted to be rotatably driven for rotating the drill bit, the drive shaft being bendable laterally to define a deflection angle thereof, and a deflection actuator coupled to the drive shaft, the deflection actuator comprising a rotatable deflection housing surrounding the drive shaft and an elongated deflection piston rotatable with the deflection housing and movable in the deflection housing for applying a lateral bending force along the length of the drive shaft for bending the drive shaft for making changes in the deflection angle of the drive shaft which is transmitted to the drill bit as an inclination angle steering adjustment;

in which the rotary section is coupled to the deflection actuator and includes a rotator actuator aligned axially with the deflection housing and surrounding the drive shaft and rotatably coupled to the deflection housing for transmitting a rotational force to the deflection housing, the rotator actuator movable in proportion to a desired change in the azimuth angle to rotate the deflection housing and the deflection piston to thereby change the rotational angle at which the lateral bending force is applied to the drive shaft to transmit to the drill bit an azimuth angle steering adjustment; and

in which the telemetry section includes sensors for measuring the inclination angles and the azimuth angles of the steering tool while drilling, input signals proportional to the desired inclination angle and azimuth angle of the steering tool, and a feedback loop for processing measured and desired inclination angle and azimuth angle command signals, respectively, for controlling operation of the deflection actuator for making inclination angle steering adjustments and for separately controlling operation of the rotary actuator for making azimuth angle steering adjustments.

2. The improvement according to claim 1 in which the conduit is an elongated rotary drill string.

3. The improvement according to claim 1 in which the conduit is a coiled tubing, and in which the drill bit is rotated by a downhole motor.

4. The improvement according to claim 1 in which the rotator actuator includes a rotator piston movable in proportion to the desired change in the azimuth angle and a helical gear arrangement on the deflection housing coupled to the rotator piston and rotatable in response to rotator piston travel to rotate the deflection housing and thereby rotate the deflection piston to change the azimuth angle at the drill bit.

5. The improvement according to claim 1 in which the lateral bending force is applied by a hydraulically powered bending force applied to the deflection piston by drilling mud taken from an annulus between the conduit and the borehole.

6. The improvement according to claim 1 in which the deflection actuator applies the bending force to the drive shaft while the rotator actuator applies the rotational force to the drive shaft for making simultaneous adjustments to the inclination angles and the azimuth angles.

7. The improvement according to claim 1 in which the feedback loop comprises a closed loop controller including a comparator for receiving the measured and desired inclination angle and azimuth angle command signals for producing inclination and azimuth error signals for making the steering adjustments.

8. The improvement according to claim 1 in which the telemetry section comprises an onboard mud pulse telemetry section for receiving the desired inclination and azimuth angle input signals and utilizing mud pulse controls for operating the deflection actuator and the rotator actuator from drilling mud taken from an annulus between the conduit and the borehole.

9. The improvement according to claim 8 in which the mud pulse telemetry section provides open loop control to the deflection actuator and the rotator actuator, and in which electrical controls provide closed loop control to the actuators.

10. The improvement according to claim 1 in which opposite ends of the drive shaft are supported by axially spaced-apart end bearings mounted adjacent opposite ends of the deflection housing, and the deflection piston applies the lateral bending force to the drive shaft between the end bearings to bend and thereby deflect the drive shaft into the deflection housing while the end bearings constrain the opposite ends of the drive shaft.

11. Apparatus according to claim 1 in which the deflection piston contained in the deflection housing is positioned on one side of the drive shaft and the drive shaft has a longitudinal axis aligned with a longitudinal axis of the deflection housing, and the lateral bending force is applied by the piston as a unitary force which physically bends the drive shaft to deflect its longitudinal axis away from the axis of the deflection housing.

12. A three-dimensional steering tool for use in drilling a borehole in an underground formation in which an elongated conduit extends from the surface through the borehole and in which the steering tool is mounted on the conduit near a drill bit for drilling the borehole, the steering tool comprising an integrated telemetry section, rotary section and flex section aligned axially along the steering tool for separately controlling inclination and azimuth angles at the drill bit;

in which the steering tool includes an elongated drive shaft coupled between the conduit and the drill bit, the drive shaft adapted to be rotatably driven for rotating the drill bit;

in which the flex section includes a deflection actuator for applying a lateral bending force to the drive shaft for bending the drive shaft to produce a drive shaft deflection angle for making corresponding inclination angle adjustments at the drill bit;

in which the deflection actuator comprises a rotatable deflection housing surrounding the drive shaft and an elongated deflection piston rotatable with the deflection housing and movable in the deflection housing for applying the lateral bending force to the drive shaft;

in which the rotary section includes a rotator actuator coupled to the deflection actuator for applying a rotational force to the deflection actuator for changing the rotational angle at which the lateral bending force is applied to the drive shaft for making corresponding azimuth angle adjustments at the drill bit;

in which the rotator actuator is aligned axially with the deflection housing and rotatably coupled to the deflection housing for transmitting a rotational force to the deflection housing, the rotator actuator movable in proportion to a desired change in the azimuth angle to rotate the deflection housing and the deflection piston for changing the angle at which the lateral bending force is applied; and

in which the telemetry section measures the inclination angle and the azimuth angle during drilling and compares them with desired inclination and azimuth angle information to produce inclination control signals for operating the deflection actuator to make steering adjustments in the inclination angle and for separately producing azimuth control signals for operating the rotator actuator for making steering adjustments in the azimuth angle.

13. Apparatus according to claim 12 in which the conduit is an elongated rotary drill string.

14. Apparatus according to claim 12 in which the conduit is a coiled tubing, and in which the drill bit is rotated by a downhole motor.

15. Apparatus according to claim 12 in which the deflection actuator comprises an elongated deflection housing surrounding the drive shaft, and an elongated hydraulically operated piston in the deflection housing for applying the bending force distributed lengthwise along the drive shaft for flexing the drive shaft laterally to produce said deflection angle thereof to thereby change the inclination angle at the drill bit.

16. Apparatus according to claim 15 in which the rotator actuator is coupled to the deflection housing and includes a rotator piston movable in proportion to a desired change in the azimuth angle and a helical gear arrangement on the deflection housing coupled to the rotator piston and rotatable in response to piston travel to rotate the deflection housing to change the azimuth angle at the drill bit.

17. Apparatus according to claim 15 in which the hydraulically powered bending force is applied to the deflection piston by drilling mud taken from an annulus between the conduit and the borehole.

18. Apparatus according to claim 12 in which the deflection actuator applies the bending force to the drive shaft while the rotary actuator applies the rotational force to the deflection actuator for making simultaneous adjustments in the inclination angles and the azimuth angles.

19. Apparatus according to claim 12 in which the feedback loop comprises a closed loop controller including a comparator for receiving the measured and desired inclination angle and azimuth angle command signals for producing inclination and azimuth error signals for making the steering adjustments.

20. Apparatus according to claim 12 in which the telemetry section comprises an onboard mud pulse telemetry section for receiving the desired inclination and azimuth angle input signals and utilizing mud pulse controls for operating the deflection actuator and the rotator actuator from drilling mud taken from an annulus between the conduit and the borehole.

21. The apparatus according to claim 20 in which the mud pulse telemetry section provides open loop control to the deflection actuator and the rotator actuator, and in which electrical controls provide closed loop control to the actuators.

22. Apparatus according to claim 12 in which the deflection actuator includes axially spaced-apart end bearings for mounting the drive shaft along a longitudinal axis of the steering tool, and a deflection piston for applying the lateral bending force to the drive shaft between the end bearings to bend the drive shaft while the end bearings constrain the drive shaft on opposite sides of the deflection piston.

23. Apparatus according to claim 12 in which the deflection piston contained in the deflection housing is positioned on one side of the drive shaft and the drive shaft has a longitudinal axis aligned with a longitudinal axis of the deflection housing, and the lateral bending force is applied by the piston as a unitary force which physically bends the drive shaft to deflect its longitudinal axis away from the axis of the deflection housing.

24. A three-dimensional steering tool for use in drilling a borehole in an underground formation in which a rotary drill string extends from the surface through the borehole, and the steering tool is coupled to the rotary drill string at one end and to a drill bit at the other end for drilling the borehole, the steering tool comprising an integrated telemetry section, rotary section and flex section aligned axially along the steering tool for separately controlling inclination and azimuth angles at the drill bit;

in which the steering tool includes an elongated drive shaft coupled between the drill string and the drill bit for rotating with the rotation of the rotary drill string when drilling the borehole;

in which the flex section comprises a deflection actuator which includes a rotatable deflection housing surrounding the drive shaft and an elongated deflection piston rotatable with the deflection housing and movable in the deflection housing for applying a lateral bending force along a length of the drive shaft during the rotation of the drill string for changing a deflection angle of the drive shaft to thereby make inclination angle steering adjustments at the drill bit;

the rotary section including a rotator housing aligned axially with the deflection housing and surrounding the drive shaft and rotatably coupled to the deflection housing, and a rotator piston contained in the rotary housing, the rotator piston movable in proportion to a desired change in the azimuth angle, for applying a rotational force to the deflection housing to rotate the deflection housing and the deflection piston to change a rotational angle at which the deflection piston applies the lateral bending force to the drive shaft during rotation of the drill string to thereby make azimuth angle steering adjustments at the drill bit;

the telemetry section measuring present inclination angles and azimuth angles during drilling and comparing them with desired inclination and azimuth angle information to separately produce inclination control signals for operating the deflection piston and azimuth control signals for operating the rotator piston to make steering adjustments in azimuth.

25. Apparatus according to claim 24 in which the rotator actuator is coupled to the deflection housing and includes a rotator piston movable in proportion to a desired change in the azimuth angle and a helical gear arrangement on the deflection housing coupled to the rotator piston and rotatable in response to piston travel to rotate the deflection housing to change the azimuth angle at the drill bit.

26. Apparatus according to claim 25 in which the hydraulically powered bending force is applied to the deflection piston by drilling mud taken from an annulus between the conduit and the borehole.

27. Apparatus according to claim 24 in which the deflection actuator applies the bending force to the drive shaft while the rotator actuator applies the rotational force to the drive shaft for making simultaneous adjustments to the inclination angles and the azimuth angles.

28. Apparatus according to claim 24 in which the feedback loop comprises a closed loop controller including a comparator for receiving the measured and desired inclination angle and azimuth angle command signals for producing inclination and azimuth error signals for making the steering adjustments.

29. Apparatus according to claim 24 in which the telemetry section comprises an onboard mud pulse telemetry section for receiving the desired inclination and azimuth angle signals from the surface and utilizing mud pulse controls for operating the deflection actuator and rotator actuator from drilling mud taken from an annulus between the conduit and the borehole.

30. Apparatus according to claim 29 in which the mud pulse telemetry section provides open loop control to the deflection actuator and the rotator actuator, and in which electrical controls provide closed loop control to the actuators.

31. Apparatus according to claim 24 in which opposite ends of the drive shaft are supported by axially spaced-apart end bearings mounted adjacent opposite ends of the deflection housing, and the deflection piston applies the lateral bending force to the drive shaft between the end bearings to bend and thereby deflect the drive shaft into the deflection housing while the end bearings constrain the opposite ends of the drive shaft.

32. Apparatus according to claim 24 in which the deflection piston contained in the deflection housing is positioned on one side of the drive shaft and the drive shaft has a longitudinal axis aligned with a longitudinal axis of the deflection housing, and the lateral bending force is applied by the piston as a unitary force which physically bends the drive shaft to deflect its longitudinal axis away from the axis of the deflection housing.

33. A 3D steering tool adapted for steering a well drilling apparatus when drilling a borehole in an underground formation, comprising:

an elongated drive shaft coupled to a drill bit and adapted to be rotatably driven for rotating the drill bit, the drive shaft being bendable laterally to define a deflection angle thereof;

a deflection actuator for applying a lateral bending force along the length of the drive shaft for bending the drive shaft for making changes in the deflection angle to thereby transmit an inclination angle adjustment to the drill bit;

the deflection actuator comprising a rotatable deflection housing surrounding the drive shaft and an elongated deflection piston rotatable with the deflection housing and movable in the deflection housing for applying a lateral bending force to the drive shaft;

a rotator actuator coupled to the deflection actuator for transmitting a rotational force to the deflection actuator to thereby change the rotational angle at which the lateral bending force is applied to the drive shaft to thereby transmit an azimuth angle adjustment to the drill bit;

in which the rotator actuator is aligned axially with the deflection housing and rotatably coupled to the deflection housing for transmitting a rotational force to the deflection housing, the rotator actuator movable in proportion to a desired change in the azimuth angle to rotate the deflection housing and the deflection piston to thereby change the rotational angle at which the lateral bending force is applied to the drive shaft to transmit to the drill bit an azimuth angle steering adjustment; and

a telemetry system contained on the steering tool for separately controlling the lateral bending force and the rotational force for steering the drill bit along a predetermined course.

34. Apparatus according to claim 33 in which the deflection actuator comprises an elongated deflection housing surrounding the drive shaft, and an elongated deflection piston in the deflection housing for applying the bending force distributed lengthwise along the drive shaft for flexing the drive shaft laterally to produce said deflection angle.

35. Apparatus according to claim 34 in which the rotator actuator is coupled to the deflection housing and includes a rotator piston movable in proportion to a desired change in azimuth angle and in which the rotator piston is coupled to the deflection housing which responds to piston travel to rotate the deflection housing to change the azimuth angle at the drill bit.

36. Apparatus according to claim 33 in which the deflection actuator includes axially spaced-apart end bearings for mounting the drive shaft along a longitudinal axis of the steering tool, and a deflection piston for applying the lateral bending force to the drive shaft between the end bearings to bend the drive shaft while the end bearings constrain the drive shaft on opposite sides of the deflection piston.

37. Apparatus according to claim 33 in which the deflection piston contained in the deflection housing is positioned on one side of the drive shaft and the drive shaft has a longitudinal axis aligned with a longitudinal axis of the deflection housing, and the lateral bending force is applied by the piston as a unitary force which physically bends the drive shaft to deflect its longitudinal axis away from the axis of the deflection housing.