Drill pipe downhole unthreading apparatus
This paper describes an apparatus for unthreading a threaded connection in a drill string. It comprises: an elongate shaft; fluid powered means for moving the shaft in repeated movement between first and second positions; upper and lower mandrels supporting the shaft and exposed to joints making up the drill string, the mandrels joining together to permit rotation therebetween; upper and lower pipe gripping means cooperatively engaging pipe joints in the drill string wherein the upper pipe gripping means engages a pipe joint above a threaded connection in the pipe string and the lower pipe gripping means engages a pipe joint below the threaded connection in the pipe string; and means coupling the shaft to impart repeated movement through the upper and lower mandrels and pipe gripping means to the pipe joints so that the threaded connection in the pipe string is rotated to unthread.
- Assignee:
- Halliburton Logging Services, Inc., Houston, TX (USA)
- Patent Number(s):
- US 5024272; A
- Application Number:
- PPN: US 7-520324
- OSTI ID:
- 5799586
- Country of Publication:
- United States
- Language:
- English
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