Patent ID: 6719262
Filing Date: 2004-04-13
Classification: E21B

Abstract:
A method of operating a bidirectional scaling ram-type blowout preventer, comprising: bidirectional sealing rams having top seals, bottom seals and front packers, operable by corresponding linear actuators for movement in corresponding guideways within a central housing to selectively seal the annulus around a pipe located within a central vertical passageway through the central housing, a selectively operable first fluid communication system between the central vertical passageway below the level of the ram packers and locations in the first and second guideways behind the rams, first control apparatus, comprising at least a first valve, for opening and closing the first fluid communication system, a selectively operable second fluid communication system between the central vertical passageway above the level of the ram packers and locations in the first and second guideways behind the rams, and second control apparatus, comprising at least a second valve, for opening and closing the second fluid communication system, having the steps of:a. opening one and closing the other of the first and second fluid communication systems; and b. operating the linear actuators to selectively move the rams in the corresponding guideways.