Remotely operable hydraulic underreamer
US6378632B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1999 |
| Grant date | Apr 30, 2002 |
| Priority date | — |
| Expiry date | Oct 28, 2019 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B10/345
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An underreamer opens a borehole below a restriction that is larger than the restriction itself. The underreamer includes cutters which engage the formation by traversing outward and upward. The force pushing the cutters to the extended position is supplied by a piston built into each cutter support. Pressure acting on these pistons comes from the pressure differential between the annulus and drill string during circulation of drilling fluid. The cutters are supported on both sides of the cutting structure by arms that are supported by and in sliding contact with the body. A spring opposes the upward and outward motion of the cutter mechanism and returns the cutters to their collapsed position in the absence of differential pressure. The body of the tool incorporates by-pass ports for transmitting fluid through the tool to the remainder of the bottom hole assembly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.