Method and apparatus for deepwater drilling
US4813495A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 5, 1987 |
| Grant date | Mar 21, 1989 |
| Priority date | — |
| Expiry date | May 5, 2007 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B33/085
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A method and apparatus for drilling subsea wells in water depths exceeding 3000 feet (preferably exceeding 4000 feet). Drilling mud returns are taken at the seafloor and pumped to the surface by a centrifugal pump that is powered by a seawater driven turbine. A low-differential pressure rotating head seats in the upper tapered portion of the longitudinal throughbore of an upper stack package which is attached to the top of the blowout preventer stack and seals against the drill string as it is run in and out of the borehole. The method and apparatus of the present invention enable higher mud weights to be used than can be used in conventional techniques which allows kicks to be more easily controlled, fewer casing strings to be run, and overall drilling time reduced by up to 40%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.