Electromagnetic anti-jam telemetry tool
A mud-pulse telemetry tool includes a tool housing, a motor disposed in the tool housing, and a magnetic coupling coupled to the motor and having an inner shaft and an outer shaft. The tool may also include a stator coupled to the tool housing, a restrictor disposed proximate the stator and coupled to the magnetic coupling, so that the restrictor and the stator adapted to generate selected pulses in a drilling fluid when the restrictor is selectively rotated. The tool may also include a first anti-jam magnet coupled to the too housing, and an second anti-jam magnet disposed proximate the first anti-jam magnet and coupled to the inner shaft and/or the outer shaft, wherein at least one of the first anti-jam magnet and the second anti-jam magnet is an electromagnet, and wherein the first anti-jam magnet and the second anti-jam magnet are positioned with adjacent like poles.
1. A mud-pulse telemetry tool, comprising:
a tool housing;
a motor disposed in the tool housing;
a magnetic coupling coupled to the motor and having an inner shaft and an outer shaft;
a stator coupled to the tool housing;
a restrictor disposed proximate the stator and coupled to the magnetic coupling, the restrictor and the stator adapted to generate selected pulses in a drilling fluid when the restrictor is selectively rotated;
a first anti-jam magnet coupled to the tool housing; and
an second anti-jam magnet disposed proximate the first anti-jam magnet and coupled to one selected from the inner shaft and the outer shaft,
wherein at least one of the first anti-jam magnet and the second anti-jam magnet is an electromagnet, and wherein the first anti-jam magnet and the second anti-jam magnet are positioned with adjacent like poles.
2. The mud-pulse telemetry tool of claim 1 , wherein the first anti-jam magnet is an electromagnet.
3. The mud-pulse telemetry tool of claim 2 , wherein the second anti-jam magnet is a second electromagnet.
4. The mud-pulse telemetry tool of claim 1 , wherein the first anti-jam magnet is coupled to the outer shaft.
5. The mud-pulse telemetry tool of claim 1 , wherein the restrictor is coupled to the outer shaft of the magnetic coupling.
6. The mud-pulse telemetry tool of claim 5 , further comprising a spring positioned to prevent the outer shaft from impacting the tool housing.
7. The mud-pulse telemetry tool of claim 1 , further comprising a radial bearing.
8. The mud-pulse telemetry tool of claim 1 , further comprising a thrust bearing.
9. The mud-pulse telemetry tool of claim 8 , wherein the thrust bearing is disposed proximate the first anti-jam magnet and around the inner shaft.
10. The mud-pulse telemetry tool of claim 8 , wherein the thrust bearing is disposed proximate a coupling that couples the outer shaft to a shaft of the restrictor such that the thrust bearing is not formed around the inner shaft.
11. The mud-pulse telemetry tool of claim 1 , wherein restrictor and the stator are disposed proximate a first end of the tool, and the first anti-jam magnet and the second anti-jam magnet are disposed proximate a second end of the tool.
12. The mud-pulse telemetry tool of claim 1 , further comprising a downhole computer configured to energize the electromagnet among the first anti-jam magnet and the second anti-jam magnet when the downhole computer detects a jammed condition.
13. A method of relieving a jam in a mud-pulse tool, comprising:
detecting a jam in the mud-pulse tool;
energizing an electromagnet coupled to one of a of mud-pulse tool housing and a magnetic coupling,
wherein a magnet is disposed proximate the electromagnet and coupled to the other of the tool housing and the magnetic coupling, wherein the electromagnet and the magnet are positioned with adjacent like poles; and
de-energizing the electromagnet.
14. The method of claim 13 , further comprising detecting an unjammed condition.
15. The method of claim 14 , wherein the electromagnet is coupled to the tool housing and the magnet is coupled to an outer shaft of the magnetic coupling.
16. The method of claim 14 , wherein the energizing an electromagnet comprises energizing a first electromagnet and energizing a second electromagnet.
17. A downhole tool, comprising:
a tool housing;
a motor disposed in the tool housing;
a magnetic coupling coupled to the motor and having an inner shaft and an outer shaft;
a stator coupled to the tool housing;
a restrictor disposed proximate the stator and coupled to the magnetic coupling, the restrictor and the stator adapted to generate selected pulses in a drilling fluid when the restrictor is selectively rotated;
a first anti-jam magnet coupled to the too housing; and
an second anti-jam magnet disposed proximate the first anti-jam magnet and coupled to one selected from the inner shaft and the outer shaft,
wherein at least one of the first anti-jam magnet and the second anti-jam magnet is an electromagnet, and wherein the first anti-jam magnet and the second anti-jam magnet are positioned with adjacent like poles.
18. The mud-pulse telemetry tool of claim 17 , wherein the first anti-jam magnet is an electromagnet.
19. The mud-pulse telemetry tool of claim 18 , wherein the second anti-jam magnet is a second electromagnet.
20. The mud-pulse telemetry tool of claim 17 , further comprising a downhole computer configured to energize the electromagnet among the first anti-jam magnet and the second anti-jam magnet when the downhole computer detects a jammed condition.