The Bureau of Safety and Environmental Enforcement (BSEE) investigated a gas-release incident in the Gulf of Mexico. The case highlights anchor-handling risks during offshore operations and provides lessons to improve planning, communication, and procedural compliance.
What Happened
A diver support vessel (DSV) was engaged in recovering two bow anchors from the seafloor near a subsea well site ahead of recompletion work by a jack-up rig. While maneuvering down current, the vessel’s No. 1 bow-anchor wire became entangled in the well. Despite repeated efforts to free the wire, it snagged on the annulus-valve assembly, shearing several studs and detaching the valve from the tubing spool. This caused a significant gas plume to reach the surface. The DSV retreated approximately 1,900 feet, and an emergency response was initiated. However, several key preparation steps had not been completed by the lease operator before mobilization.
Why It Happened
The incident occurred due to inadequate planning and coordination between the operator and contractor. A simultaneous operations (SIMOPS) meeting and hazard assessment were not conducted, and the Safety and Environmental Management System (SEMS) plan did not clearly define when such steps were required. Communication failures compounded the situation, as key personnel were not informed when the job began or what tasks were being carried out. The absence of an anchor tug made it difficult for the vessel to hold position in strong currents, increasing the risk of entanglement. Once the emergency occurred, response efforts were hindered because critical drawings were not readily available and the replacement valve was not configured for diver handling, delaying the securing of the release.
Actions Taken
Corrective actions focused on improving procedural clarity, equipment readiness, and communication. These included the recommendation for pre-job checklists, clearer SEMS requirements, better contingency planning, and stakeholder coordination before mobilization.
Lessons Learned
- Use a pre-job checklist to confirm all preparatory steps, including marking pipelines and considering weather or delays.
- Revalidate all critical steps if delays occur before remobilizing.
- Conduct formal SIMOPS and hazard assessments to identify and control risks.
- Hold a pre-mobilization review with all stakeholders to confirm scope, readiness, and safety measures.
- Ensure clear communication between vessel crews, contractors, and operators at every stage.
- Include anchor-handling strategies that account for currents and vessel drift.
- Confirm that critical documentation is available onboard before operations.
- Ensure subsea installation or repair planning involves divers directly.
- Provide refresher training on offshore planning, communication, and procedural compliance.
- Update SEMS protocols to define when SIMOPS and hazard assessments are mandatory.
Did you subscribe to our Daily newsletter?
It’s Free! Click here to Subscribe!
Source: Safety4Sea
