| 摘要 |
The present invention relates to a blow out preventer (BOP) for use in the drilling of a wellbore into a subterranean fluid reservoir and / or the production of fluid, typically hydrocarbon fluids, from such a reservoir, in particular to a new configuration of BOP which may have a smaller outer diameter for a given operating force than conventional BOPs. The new BOP comprises a housing which has a longitudinal axis and which is divided in a first housing part and a second housing part, movement of the first housing part relative to the second housing part being prevented by fasteners, each fastener including a shaft which extends through a fastener receiving passage provided in the first housing part into a fastener receiving passage provided in the second housing part, the housing being further provided with fluid flow passages which extend from the first part of the housing to the second part of the housing, the fluid flow passages being interspersed between fastener receiving passages. In one embodiment of the invention, three annular BOPs according to this design are integrated to form a stack. A seal assembly is mounted in a central bore of the bore, the lowermost end of the seal assembly being supported on a locking dog which extends from the BOP housing into the central bore. The locking dog is movable, for example using hydraulic actuation means, and can be retracted into the wall of the BOP housing. |
