Reliability of deepwater subsea blowout preventers

Operational experience data from deepwater subsea blowout preventers (BOP's ) used in the U.S. Gulf of Mexico (GOM) in 1997 and 1998 have been collecte d and analyzed to reveal BOP reliability problems. Results focus on rig dow ntime caused by BOP failures, criticality of failures in terms of ability t o control a well kick, and BOP subsea test-time consumption. Results have b een compared with corresponding results from previous BOP reliability studi es carried out for other areas and periods. An overall conclusion is that t here are no main differences in overall reliability of deepwater BOP's vs. BOP's operating in "normal" water depths, except for increased downtime cau sed by increased BOP handling time in deep waters.