Repetitive Pulsed Electric Discharge Apparatuses and Methods of Use

• US 20160017663A1
• Filed: 06/18/2015
• Published: 01/21/2016
• Est. Priority Date: 06/29/2006
• Status: Active Grant

• Current Assignee: SDG, LLC
• Original Assignee: SDG, LLC
• Inventors: Moeny, William M.
• Granted Patent: US 10,060,195 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: E21B 17/003 with electrically conducting or insulating means E21B17/028 and E21B17/023 take precedence
• CPC Class Codes: E21B 7/15 of electrically generated heat

Abstract

Electrocrushing drills and methods for operating electrocrushing drills. Electrocrushing drill bits comprise one or more high voltage electrodes surrounded by a ground or current return structure, which can be a ring or a comprise rod shaped electrodes. Openings in the rim of the current return structure facilitate removal of drilling debris and bubbles created by the electrocrushing process out from the bottom face of the bit and up the wellbore. The high voltage electrodes can be arranged in a circle. The current return structure may partially cover the bottom face of the drill bit, thereby enclosing the high voltage electrodes in openings that may be sector shaped. Also a method and apparatus for interrupting communications between downhole data acquisition systems and a surface controller system during each drill pulse, thereby reducing noise. A direct connection between the two systems enables high speed communications, thereby improving safety by providing the operator with more advance warning of a possible blowout. Also a method and apparatus for dividing a flow of drilling fluid both to sweep drilling debris and bubbles out of the drill bit and hole and to cool high power electrical components.

Claims

1. An electrocrushing drill bit comprising one or more high voltage electrodes surrounded by a current return structure comprising a plurality of circumferential openings for facilitating removal of drilling debris from said drill bit.

2. The drill bit of claim 1 comprising a plurality of rod shaped high voltage electrodes arranged in at least a portion of a circle.

3. The drill bit of claim 2 wherein said high voltage electrodes surround one or more rod shaped central current return electrodes.

4. The drill bit of claim 3 comprising a plurality of central current return electrodes are arranged in at least a portion of a circle concentric with said high voltage electrodes.

5. The drill bit of claim 1 wherein said current return structure comprises a current return ring.

6. The drill bit of claim 5 wherein said current return ring is sufficiently strong to structurally support a drill string.

7. The drill bit of claim 1 wherein said current return structure comprises a plurality of rod shaped circumferential current return electrodes located at an outer rim of said drill bit and said circumferential openings comprise spaces between said circumferential current return electrodes.

8. The drill bit of claim 7 wherein said circumferential current return electrodes are concentric with a plurality of high voltage electrodes arranged in at least a portion of a circle.

9. The drill bit of claim 8 further comprising a central current return electrode located approximately at a center of said circle.

10. The drill bit of claim 7 further comprising a wall connecting said circumferential current return electrodes, said wall thinner than a diameter of each said circumferential current return electrode and disposed so that said wall extends radially outwardly as far as or beyond said circumferential current return electrode, thereby longitudinally extending an outer wall of the drill bit, but does not extend radially inwardly past said circumferential current return electrodes.

11. The drill bit of claim 10 wherein a height of said wall is shorter than a length of said circumferential current return electrodes.

12. The drill bit of claim 10 wherein said wall and said circumferential current return electrodes are manufactured together to form a single structure.

13. The drill bit of claim 10 wherein said wall comprises a plurality of additional openings to facilitate removal of drilling debris from the drill bit.

14. The drill bit of claim 7 wherein said circumferential current return electrodes comprise a cross-sectional shape selected from the group consisting of circle, ellipse, wedge, and airfoil.

15. The drill bit of claim 7 comprising a single high voltage electrode surrounded by a plurality of circumferential current return electrodes.

16. The drill bit of claim 1 comprising a plurality of channels running longitudinally along an outer surface of said drill bit to facilitate transport of drilling debris up and out of a drilling hole.

17. The drill bit of claim 1 wherein said current return structure partially covers a bottom face of said drill bit, said current return structure comprising one or more bottom openings along said bottom face, wherein one or more of said high voltage electrodes is disposed within each said bottom opening.

18. The drill bit of claim 17 further comprising an channel at approximately a center of said bottom face for flowing drilling fluid into said bit.

19. The drill bit of claim 18 wherein said current return structure comprises a solid portion disposed near said channel, thereby forcing at least some of the flowing drilling fluid to flow radially from said channel toward and around each said high voltage electrode.

20. The drill bit of claim 18 wherein the flowing drilling fluid sweeps drilling debris and bubbles in said fluid created by operation of said electrodes out of said drill bit.

21. The drill bit of claim 17 wherein said high voltage electrodes are rod shaped.

22. The drill bit of claim 21 wherein the high voltage electrodes are arranged to form at least a portion of a circle centered on a center of said bottom face.

23. The drill bit of claim 17 wherein each said high voltage electrode is compressible and/or extends out from said bottom face.

24. The drill bit of claim 17 wherein two or more of said high voltage electrodes are electrically connected to form one or more sets of connected electrodes, each set powered by a separate pulsed power system.

25. The drill bit of claim 24 wherein preferred operation of one or more of said sets over one or more other of said sets results in directional control of said drill bit.

26. The drill bit of claim 24 wherein electrodes in each set are mechanically linked to move together.

27. The drill bit of claim 17 wherein each said bottom opening is sector-shaped or substantially triangular.

28. The drill bit of claim 27 wherein said high voltage electrodes are substantially triangular or sector shaped and are circumferentially arranged around a center of said bottom face, each high voltage electrode oriented so that one of its vertices is pointing toward said center.

29. The drill bit of claim 1 connected to a bottom hole assembly via a rotational joint and a motor for nutating said drill bit.

30. The drill bit of claim 29 wherein nutation of said drill bit results in more uniform drilling despite non-uniform electric field distributions produced by said high voltage electrodes.