Blowout Preventer (BOP)
A blowout preventer (BOP) is a large valve assembly installed on the wellhead during drilling, completion and workover operations to seal the well and control formation pressure if a kick occurs. Annular preventers use a reinforced elastomer packing element that closes around pipe of various sizes or, in many designs, the open hole. Ram preventers use opposing steel rams: pipe rams seal around the drill pipe, blind rams seal the open bore, and shear rams cut the pipe and seal the wellbore. Several preventers are combined into a BOP stack and operated hydraulically from an accumulator control unit. Equipment is designed to API Spec 16A, control systems to API Spec 16D, and well control equipment system requirements are set out in API Standard 53. Selection parameters include bore size, rated working pressure, ram configuration, shear capability and sour-service rating.
Examples
- Annular BOP at the top of a land rig stack
- Double ram BOP with pipe and blind-shear rams
- Workover BOP for well intervention