Drill bit assembly for directional drilling

• US 7,360,610 B2
• Filed: 01/18/2006
• Issued: 04/22/2008
• Est. Priority Date: 11/21/2005
• Status: Expired due to Fees

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: NovaDrill, Inc. (Schlumberger NV)
• Inventors: Hall, David R., Dahlgren, Scott, Lundgreen, David, Leany, Francis E., Wise, Daryl N.
• Primary Examiner(s): DANG, HOANG C
• Application Number:
  US11/306,976
• Publication Number:
  US 20070114068A1
• Time in Patent Office: 825 Days
• Field of Search: 175/73, 175/61, 175/385, 175/399
• US Class Current: 175/61
• CPC Class Codes: E21B 10/62 characterised by parts, e.g. cutting elements, which are detachable or adjustable E21B10/64 takes precedence; for roller bits E21B10/20; for augers E21B10/44
• CPC Class Codes: E21B 7/064 specially adapted drill bits therefor
• CPC Class Codes: E21B 7/067 with means for locking sections of a pipe or of a guide for a shaft in angular relation, e.g. adjustable bent sub

Abstract

In one aspect of the invention a drill bit assembly has a body portion intermediate a shank portion and a working portion, the working portion having at least one cutting element. A shaft is supported by the body portion and extends beyond the working portion. The shaft also has a distal end that is rotationally isolated from the body portion. In another aspect of the invention, a method for steering a downhole tool string has the following steps: providing a drill bit assembly attached to an end of the tool string disposed within a bore hole; providing a shaft extending beyond a working portion of the assembly; engaging a subterranean formation with a distal end of the shaft; and angling the drill bit assembly with the shaft along a desired drilling trajectory.

Claims

1. A drill bit assembly, comprising:

a body portion intermediate a shank portion and a working portion;

the working portion comprising at least one cutting element; and

at least a portion of a shaft is disposed within the body portion and protrudes from the working portion; and

the shaft comprising a distal end rotationally isolated from the body portion;

wherein during a drilling operation, a distal end of the shaft is rotationally stationary with respect to a subterranean formation and the body portion is adapted to rotate around the shaft.

2. The drill bit assembly of claim 1, wherein the assembly further comprises an actuator adapted to move the shaft relative to the working portion.

3. The drill bit assembly of claim 2, wherein the actuator is also rotationally isolated from the body portion.

4. The drill bit assembly of claim 2, wherein the actuator moves the shaft parallel, normal, or diagonally with respect to an axis of the body portion.

5. The drill bit assembly of claim 2, wherein the actuator comprises a latch, hydraulics, a magnetorheological fluid, eletrorheological fluid, a magnet, a piezoelectric material, a magnetostrictive material, a piston, a sleeve, a spring, a solenoid, a ferromagnetic shape memory alloy, swash plate, a collar, a gear, or combinations thereof.

6. The drill bit assembly of claim 2, wherein the actuator is in communication with a downhole telemetry system.

7. The drill bit assembly of claim 1, wherein at least a portion of the shaft is disposed within a chamber formed in the body portion.

8. The drill bit assembly of claim 7, wherein a sleeve is disposed within the chamber and surrounds the shaft.

9. The drill bit assembly of claim 8, wherein the sleeve is also rotationally isolated from the body portion.

10. The drill bit assembly of claim 1, wherein the distal end comprises a superhard material.

11. The drill bit assembly of claim 1, wherein the shank portion is adapted for connection to a downhole tool string component.

12. The drill bit assembly of claim 1, wherein the shaft substantially shares a central axis with the shank portion.

13. The drill bit assembly of claim 1, wherein a brake is disposed within the chamber and is adapted to engage the shaft.

14. The drill bit assembly of claim 1, wherein the distal end of the shaft comprises an asymmetnc geometry.

15. A method for steering a downhole tool string, comprising:

providing a drill bit assembly attached to an end of the tool string disposed within a bore hole;

providing a shaft protruding from a working portion of the drill bit assembly, the working portion comprising at least one cutting element;

engaging the formation with a distal end of the shaft, the shaft being part of the drill bit assembly; and

angling the drill bit assembly with the shaft along a desired trajectory;

wherein during a drilling operation, a distal end of the shall is rotationally stationary with respect to a subterranean formation and the body portion is adapted to rotate around the shaft.

16. The method of claim 15, wherein angling the drill bit assembly comprises pushing the drill bit assembly along the desired trajectory by the shaft.

17. The method of claim 15, wherein angling the drill bit assembly with the shaft comprises angling the shaft.

18. The method of claim 15, wherein the shaft advances along the desired trajectory before the drill bit assembly.

19. The method of claim 15, wherein the shaft is disposed within a chamber generally coaxial with a shank portion of the drill bit assembly.

20. The method of claim 15, wherein the shaft comprises an extending member for pushing against subterranean formation.

21. The method of claim 15, wherein the drill bit assembly comprises an actuator for angling the distal end of the shaft with respect to a shank portion of the assembly.

22. The method of claim 15, wherein the actuator is rotationally isolated from a working portion of the drill bit assembly.

23. The method of claim 15, wherein the shaft is rotationally isolated from the working portion of the drill bit assembly.

24. The method of claim 15, wherein the actuator for angling the drill bit assembly is controlled over a downhole network or a downhole tool.

25. The method of claim 15, wherein the distal end of the shaft comprises a superhard material.