Method for raising and lowering a drill string in a wellbore during drilling operations
US4646855A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 6, 1984 |
| Grant date | Mar 3, 1987 |
| Priority date | — |
| Expiry date | Nov 6, 2004 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B7/04
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A rotary well drilling system employs a drill pipe with a drill bit affixed at its lower end for the drilling of a wellbore. Drilling fluid is circulated through the drill pipe to remove drill cuttings. When raising and lowering the drill pipe in the wellbore, the drill pipe is continuously rotated along with continued drilling fluid circulation to prevent sticking of the drill pipe. The drill bit is rotated by a mud motor in the opposite direction from that of the drill pipe and at the same speed so that the drill bit remains rotationally stationary with respect to the wellbore and does not side-track as it is dragged along the lower side of the wellbore wall when being raised or lowered in an inclined wellbore.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.