Station keeping and emergency disconnecting capability for a vessel connected to a subsea wellhead in shallow water

摘要

In some embodiments, a method for executing an emergency disconnect sequence in shallow water depth includes unlatching a lower marine riser package (LMRP) of a blowout preventer (BOP) from a lower stack of the BOP. The BOP defines a wellbore fluidically coupled to the subsea wellhead. A tubular is disposed within the wellbore. The method further includes shearing the tubular and sealing the wellbore. In response to an indication that a vessel operably coupled to the BOP has failed to keep station, an unlatch sequence and a shear and seal sequence are initiated, such that each sequence occurs at least partially simultaneously. The unlatch sequence includes disconnecting the LMRP from the lower stack, and the shear and seal sequence includes activating the lower stack to shear the tubular in less than about one second and seal the wellbore.