Directional drilling of a drill string
US4807708A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 1, 1986 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Oct 1, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/068
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method of controlling the direction of a drill bit (3) at the downhole end of a drill string (2) drilling from a surface comprises providing two steerable stabilizers (4, 5) at the downhole end of the drill string (2) at locations spaced apart in the drilling direction and adjusting the orientation of the stabilizers to create reactive forces from the bore hole (6) to deflect the course of the bit (3) in a desired direction. The stabilizers (4, 5) are suitably arranged eccentrically and circumferentially offset by 180.degree..+-.60.degree.. In normal drilling the drill string (2) is rotated such that stabilizers (4, 5) engage the bore hole (6) to support a downhole motor (1) against tilting. When off course drilling is sensed the stabilizers are rotated to a position and stopped from rotation such that drilling forces generate reaction forces to cause a desired change of direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.