This accident investigation report refers to the accidental riser disconnect and subsequent uncontrolled flow during drilling operations which occurred on Mississippi Canyon Block 538 in February 2000. The Ocean Concord (semi-submersible mobile offshore drilling unit) was in the process of running a liner on drill pipe when the lower marine riser package (LMRP) was inadvertently disconnected from the blowout preventer (BOP) stack. The disconnect resulted in the discharge to the sea of approximately 806 barrels of synthetic mud from the riser and 150 barrels of synthetic mud and 150-200 barrels of crude oil from the wellbore.
Officer of the Watch 