Drill bit assembly for directional drilling

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; the distal end comprising an asymmetric geometry with a face intersecting a central axis of the shaft, which is adapted to angle the shaft;

wherein the body of the drill bit is adapted to rotate around the shaft.

2. The drill bit assembly of claim 1 , wherein the assembly further comprises an actuator adapted to mow 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 is in communication with a downhole telemetry system.

6. 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.

7. The drill bit assembly of claim 6 , wherein a sleeve is disposed within the chamber and surrounds the shaft.

8. The drill bit assembly of claim 7 , wherein the sleeve is also rotationally isolated from the body portion.

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

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

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

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

13. 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, wherein the body of the drill bit is adapted to rotate around the shaft; the distal end comprising an asymmetric geometry with a face intersecting a central axis of the shaft, which is adapted to angle the shaft;

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.

14. The method of claim 13 , wherein angling the drill bit assembly comprises pushing the drill bit assembly along the desired trajectory by the shaft.

15. The method of claim 13 , wherein angling the drill bit assembly with the shaft comprises angling the shaft.

16. The method of claim 13 , wherein the shaft advances along the desired trajectory before the drill bit assembly.

17. The method of claim 13 , wherein the shaft is disposed within a chamber generally coaxial with a shank portion of the drill bit assembly.

18. The method of claim 13 , 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.

19. The method of claim 13 , wherein the actuator is rotationally isolated from a working portion of the drill bit assembly.

20. The method of claim 13 , wherein the actuator for angling the drill bit assembly is controlled over a downhole network or a downhole tool.