Claims
- 1. A method for controlling rotational oscillations of a drill bit while drilling, said drill bit being mounted to a drilling string, said drilling string comprising a plurality of interconnected tubulars, comprising:
installing a rotational control assembly in said drilling string between a lower tubular of said drilling string and an upper tubular of said drilling string; selectively transferring torque between said upper tubular portion of said drilling string and said lower tubular of said drilling string during a drilling operation; and selectively permitting rotational slippage between said upper tubular of said drilling string and said lower tubular of said drilling string during said drilling operation in a manner which dampens or stops said rotational oscillations; and subsequently transferring torque between said upper tubular portion of said drilling string and said lower tubular of said drilling string for continuing said drilling operation.
- 2. The method of claim 1, further comprising activating said rotational control assembly to permit said rotational slippage in response to a selected acceleration of said drill bit.
- 3. The method of claim 2, further comprising hydraulicly releasing a rotational locking mechanism for a selected predetermined time period and then subsequently locking said rotational locking mechanism.
- 4. The method of claim 1, further comprising providing an electronic control for activating said rotational control assembly to permit said rotational slippage.
- 5. The method of claim 4, further comprising programming said electronic control for a selectable amount of said rotational slippage.
- 6. The method of claim 1, further comprising controlling movement of one or more hydraulic pistons.
- 7. The method of claim 2, further comprising activating said rotational control when a rotational speed of said lower tubular portion of said drilling string is less than a driving speed of said drilling operation.
- 8. An assembly for permitting rotational slippage between a lower portion of a drill string and an upper tubular of said drill string while drilling with a drill bit to thereby release torsional energy from said drill string, said assembly comprising:
a tubular housing for connecting between said lower portion of said drill string and said upper portion of said drill string; one or more moveable members within said tubular housing for controlling torque transfer between said lower portion of said drill string and said upper portion of said drill string; and a control for controlling said one or more moveable members.
- 9. The downhole apparatus of claim 8, further comprising one or more sensors for sensing a selected type of movement of said drill bit.
- 10. The downhole apparatus of claim 9, wherein said one or more sensors are sensitive to an amount of acceleration movement of said drill bit.
- 11. The downhole apparatus of claim 9, wherein said control is operable for a cycle of unlocking to permit relatively free rotation between said lower portion of said drill string and said upper portion of said drill string, and then locking to prevent rotation between said lower portion of said drill string and said upper portion of said drill string within a time period of from about fifty milliseconds to less than one second.
- 12. The downhole apparatus of claim 8, wherein said one or more moveable members comprise one or more pistons.
- 13. The downhole apparatus of claim 8, wherein said one or more moveable members comprise hydraulic pistons and one or more valves for controlling movement of said hydraulic pistons.
- 15. A method for a computer simulation of the effect of activating a rotational control mounted in a drilling string, said rotational control being operable for selectively transferring torque between tubulars in said drilling string, said method comprising:
providing parameter inputs for inputting drill string parameters describing said drilling string; providing one or more rotational control activation parameter for inputting conditions under which said rotational control is activated; and providing one or more outputs related to torsional oscillations of a drill bit of said drilling string.
- 16. The method of claim 15, further comprising plotting drill bit movement versus time wherein said rotational control is activated to permit slippage between said tubulars in said drilling string to dampen said torsional oscillations.
- 17. The method of claim 15, further comprising changing said parameter inputs to determine changes to said torsional oscillations.
- 18. The method of claim 15, wherein said drill string parameters relate to a size or length of said drilling string.
- 19. The method of claim 15, further comprising inputting parameters related to torque load changes.
- 20. The method of claim 19, further comprising monitoring said outputs to determine if said torque load changes result in torsional oscillations.
- 21. The method of claim 19, further comprising altering said torque changes to determine any resulting change in torque load oscillations.
- 22. A method for controlling drill bit oscillations of a drill bit while drilling, said drill bit being mounted to a drilling string, said drilling string comprising a plurality of interconnected tubulars, comprising:
installing a clutch assembly in said drilling string between a lower tubular of said drilling string and an upper tubular of said drilling string; selectively engaging said clutch to transfer torque between said lower tubular portion of said drilling string and said upper tubular of said drilling string during a drilling operation; and selectively disengaging said clutch to permit slippage between said upper tubular of said drilling string and said lower tubular of said drilling string during said drilling operation to thereby dampen said drill bit oscillations.
- 23. The method of claim 22, further comprising sensing movement of said drill bit which indicates said drill bit oscillations are likely to occur.
- 24. The method of claim 14, further comprising performing said step of selectively disengaging in response to said sensing.
- 25. The method of claim 24, wherein said step of engaging or disengaging further comprises selectively partially disengaging or selectively partially engaging said clutch to permit some slippage and also to transfer some torque but not all torque.
- 26. The method of claim 23, wherein said sensing movement further comprises sensing acceleration.
- 27. The method of claim 23, wherein said sensing movement further comprises sensing rotational velocity.
- 28. The method of claim 23, wherein said sensing movement further comprises sensing rotational velocity and acceleration.
- 29. The method of claim 26, further comprising sensing a selected acceleration and disengaging before a selected rotational velocity is reached.
- 30. An assembly for permitting short periods of rotational slippage between a lower portion of a drill string and an upper tubular of said drill string while drilling with a drill bit, said assembly comprising:
a tubular housing for connecting between said lower portion of said drill string and said upper portion of said drill string; one or more moveable members within said tubular housing for controlling torque transfer between said lower portion of said drill string and said upper portion of said drill string; and a control for controlling said one or more moveable members, wherein said control is operable for a cycle of unlocking for permitting rotation between said lower portion of said drill string and said upper portion of said drill string and then locking for preventing rotation between said lower portion of said drill string and said upper portion of said drill string within a time period of from about fifty milliseconds to less than one second.
- 31. The downhole apparatus of claim 30, further comprising one or more sensors for sensing a selected type of movement of said drill bit.
- 32. The downhole apparatus of claim 31, wherein said one or more sensors are sensitive to a selected acceleration of said drill bit.
- 33. The downhole apparatus of claim 30, wherein said one or more moveable members comprise one or more pistons.
- 34. The downhole apparatus of claim 30, wherein said one or more moveable members comprise hydraulic pistons and one or more valves for controlling movement of said hydraulic pistons.
Parent Case Info
[0001] The benefit of U.S. Provisional Patent Application No. 60/474,355, filed May 30, 2003, and U.S. Provisional Patent Application No. 60/485,333, filed Jul. 7, 2003, are hereby claimed, and are hereby incorporated by reference.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60474355 |
May 2003 |
US |
|
60485333 |
Jul 2003 |
US |