NTL 2000-G07 - Accidental Disconnect of Marine Drilling Risers - February 22, 2000

Recently, an incident occurred on a drillship that had the potential for causing a serious well control event. An employee was attempting to conduct a function test of the blind-shear rams. However, he inadvertently pushed the lower marine riser package (LMRP) button instead of the blind-shear ram button on the control panel. Since the LMRP button was not part of the primary or emergency disconnect sequence, the pod stabs did not retract and the blind-shear rams did not close. The disconnect allowed the release of drilling mud from the riser. Fortunately, the wellbore was cased, and a well control event caused by a loss of riser hydrostatics did not occur.