Anti-whirl underreamer
US5402856A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1993 |
| Grant date | Apr 4, 1995 |
| Priority date | — |
| Expiry date | Dec 21, 2013 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/322
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An anti-whirl underreamer comprising a body configured for connection to a drillstring, at least two arms carried by the body which are extendable between a retracted position and a projected position, a movable piston and biased spring assembly for moving the arms, a plurality of cutting elements carried by one of the arms for cutting an axially extending cylindrical sidewall of the borehole within a subterranean formation and for applying a resultant radial force to the body as it rotates, and a low friction bearing region carried by another arm for transmitting the resultant radial force from the body to the sidewall of the borehole during rotation of the underreamer within the borehole. The cutting elements are positioned so that the resultant radial force developed is of sufficient magnitude and direction to substantially maintain the low friction bearing region in contact with the sidewall of the borehole as the underreamer is rotated within the borehole.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.