Downhole steering
View Patent ↗In one aspect of the present invention, a drill string has a drill bit with a body intermediate a shank and a working face. The working face has at least one cutting element. A jack element is disposed within the drill bit body and has a distal end substantially protruding from the working face. The distal end has a primary deflecting surface having an angle relative to a central axis of the jack element of 15 to 75 degrees.
1. A drill string comprising:
a drill bit with a body intermediate a shank and a working face, the working face comprising at least one cutting element;
a jack element disposed within the drill bit body and comprising a distal end substantially protruding from the working face;
and the distal end comprising a primary deflecting surface having an angle relative to a central axis of the jack element of 15 to 75 degrees;
wherein the jack element is rotationally isolated from the drill string.
2. The drill string of claim 1 , wherein the primary deflecting surface comprises an angle relative to the central axis of 40 to 50 degrees.
3. The drill string of claim 1 , wherein the primary deflecting surface comprises a surface area of 0.5 to 4 square inches.
4. The drill string of claim 1 , wherein a tip of the distal end to the central axis of the jack element comprises a distance of 0.10 to 0.20 inch.
5. The drill string of claim 1 , wherein the primary deflecting surface and a secondary deflecting surface of the distal end form a right angle.
6. The drill string of claim 5 , wherein the secondary deflecting surface comprises a radius of curvature of 0.25 to 0.75 inch.
7. The drill string of claim 1 , wherein the primary deflecting surface comprises a radius of curvature of 0.75 to 1.25 inches.
8. The drill string of claim 1 , wherein the primary deflecting surface comprises a substantially flat portion.
9. The drill string of claim 1 , wherein the primary deflecting surface comprises a substantially circular, rectangular, elliptical, or triangular geometry.
10. The drill string of claim 1 , wherein the jack element comprises a length of 6 to 20 inches.
11. The drill string of claim 1 , wherein the jack element is supported by a bushing.
12. The drill string of claim 1 , wherein the jack element comprises carbide.
13. The drill string of claim 1 , wherein the jack element is adapted for attachment to a motor.
14. The drill string of claim 1 , wherein the distal end of the jack element comprises rounded edges.
15. The drill string of claim 1 , wherein an end of the jack element opposite the distal end has a diameter larger than a diameter of the jack element proximal the distal end.
16. The drill string of claim 1 , wherein a tip of the jack element comprises a 0.250 to 0.650 inch radius.
17. A method for steering a drill string, comprising the steps of:
providing a drill bit with a body intermediate a shank and a working face, the working face comprising at least one cutting element;
providing a rotationally isolated jack element disposed within the drill bit body and comprising a biased distal end substantially protruding from the working face;
deploying the drill bit when connected to a drill string into a borehole;
engaging the formation with the distal end of the jack element;
and steering the drill string with the jack element along a desired trajectory.
18. The method of claim 17 , wherein the distal end comprises a primary deflecting surface.
19. The method of claim 17 , wherein the drill bit comprises a build rate of 6 to 20 degrees per 100 feet drilled.