Underreamer with debris flushing flow path
US4401171A · kind A · utility
85Cited by
5References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 10, 1981 |
| Grant date | Aug 30, 1983 |
| Priority date | — |
| Expiry date | Dec 10, 2001 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/345
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An underreamer having a plurality of drilling arms hingedly attached to a tubular body for movement between a retracted position and an extended position for drilling. The underreamer includes a central wash pipe for delivering drilling mud to remove cuttings and debris from the hole during drilling and an alternate flow path, generally through the body for delivering drilling fluid to the vicinity between the arm and the body to flush debris therefrom which would prevent the arms from retracting to their normal position for withdrawal from the borehole.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.