Deepwater drill string shut-off valve system and method for controlling mud circulation
US6263981A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 24, 1998 |
| Grant date | Jul 24, 2001 |
| Priority date | — |
| Expiry date | Sep 24, 2018 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B21/10
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method is disclosed for controlling the mud circulation system for deepwater marine drilling operations in which a drill string is run from surface facilities, through a blowout preventor and into a borehole. Mud is injected into the drill string, up a borehole and through the blowout preventor adjacent the sea floor. There the mud is withdrawn from a mud exit return line near the blowout preventor and the hydrostatic head from the mud in the drill string is isolated from the relatively lesser ambient pressure at the sea floor seen at the mud exit return line with a pressure activated drill string shut-off valve when mud circulation is interrupted. A drill string shut-off valve system for controlling the mud circulation system for deepwater marine drilling operations is also disclosed. Further, a method of well control to overcome formation pressure in a well control event is disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.