Following an extreme weather event with a Mobile Offshore Drilling Unit (MODU) conducting well operations in the Gulf of Mexico, USCG and BSEE issued a joint Safety Alert to share lessons learned and highlight to operators the importance of suspending all well operations and crew changes safely when extreme weather plans are initiated.
In a recent case, a MODU, with 115 personnel onboard, lost 11 marine riser joints and a lower marine riser package (LMRP) and polluted the Gulf of Mexico with 88 barrels of miscellaneous fluids in its failed attempt to evacuate the area and evade Hurricane Ida.
The BSEE investigation concluded that the operator and contractor representatives failed to promptly start the Temporary Abandonment (TA) procedures. The TTime calculations were in the red level when the operator and contractor made a “joint decision” to suspend well operations. For several hours the TA was delayed as the operator and contractor jointly decided to conduct a crew change during an operation and reduced staffing and time constraints.
Over-torqued bolts and equipment breakdowns prevented the drill crew from retrieving the marine riser and LMRP, causing further delays. In his duty as Ultimate Work Authority, the MODU’s Captain stopped work so the crew could make storm preparations, such as placing covers on riser hatches. The captain and marine crew maneuvered the MODU with 12 riser joints and LMRP still hanging under the moonpool at speeds between 1 and 3.5 knots. Still, they could not evade Category 2+ hurricane-force wind and high/rough seas. The riser subsequently broke just below the rotary sending 11 riser joints and LMRP to the seafloor.
The USCG and BSEE strongly recommend that operators and contractors consider:
• Evaluating all considerations and associated risks and not set well operational TTimes under “optimal” conditions. These should be documented and discussed with the operations team.
• Determining the “decision time” to safely secure should start with the potential of an extreme weather event. The decision to continue well operations should not depend on a forecast track to the asset location. Don’t wait on a definitive weather forecast to react.
• Documenting contingencies for when MODUs cannot evade/evacuate extreme weather conditions. Ensure contingencies are documented in Hurricane Plans or Extreme Weather Plans. Identify search and rescue assets available to conduct a mass evacuation of personnel.
• Reviewing all approved Bridging Documents and Extreme Weather Plans before hurricane season to verify which plan takes precedence and reflects actual company operations and practices. Also, discuss documents with involved personnel, and identify and correct any training gaps.
• Reporting any challenges during attempts to evade and not follow an Extreme Weather Plan to evacuate non-essential personnel to the United States Coast Guard 8th District Command Center
• Identifying non-essential personnel and communicating that the intent is not to evacuate during extreme weather conditions.
• Suspending all well operations and crew changes safely when Hurricane or Extreme Weather Plans have been initiated
• Meeting with peer operators and contractors and developing best practices for MODUs to safely suspend well operations with extreme weather conditions, including consistent procedures to evacuate/evade. Share procedures with all personnel to promote conversations around this matter.
• Documenting all Stop Work Authority actions on Well Activity Reports Significant Events
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