Method and apparatus for annulus pressure responsive circulation and tester valve manipulation
US3970147A · kind A · utility
59Cited by
11References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 13, 1975 |
| Grant date | Jul 20, 1976 |
| Priority date | — |
| Expiry date | Jan 13, 1995 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B2200/06
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A releasably locked closed circulation valve is introduced into a well bore as part of a drill string. The annulus between the drill string and the well bore, or casing affixed to the well bore, is sealed. Pressure is applied to the annulus and the valve unlocks and opens once the annulus pressure reaches a certain level to allow circulation between the annulus and the interior of the drill string. An optional locking device preferably locks the opened valve in the open position. A second embodiment includes a tester valve simultaneously operable with the circulation valve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.