Blowout preventer shut-in assembly of last resort

摘要

A system for drilling and/or producing a subsea wellbore comprises a primary BOP comprising a primary ram BOP. In addition, the system comprises a secondary BOP releasably connected to the primary BOP, the secondary BOP comprising a secondary ram BOP. The primary ram BOP is actuatable by a first control signal. The secondary ram BOP is actuatable by a second control signal. The secondary ram BOP is not actuatable by the first control signal.