lower marine riser package – Officer of the Watch

Semi-Submersible Drilling Unit Riser Disconnect – Investigation Report

March 31, 2014 by Officer of the Watch Leave a Comment

On July 5, 2005, an unplanned riser disconnect was initiated on the Ensco 7500 semi-submersible rig, which had been engaged in exploratory drilling activities, because of unfavorable sea and wind conditions associated with an approaching tropical depression. While the riser volume was being displaced with seawater in preparation for the disconnect operation, the rig was no longer able to maintain station adequately enough to complete the operation. As a result, the riser was disconnected from the Lower Marine Riser Package (LMRP), at which time 710 barrels of synthetic-based mud was released from the riser into the GOM. At the time of the disconnect, there were no open hole hydrocarbons exposed below the casing depth.

Riser Disconnect and Blowout – Incident Investigation

July 8, 2013 by Officer of the Watch Leave a Comment

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.