During a recent anchor retrieval operation adjacent to an OCS platform, an oil emulsion pipeline was ruptured and an out-of-service water return line severely damaged. A workboat on contract to an OCS operator was attempting to retrieve a mooring buoy anchor and its chain. The mooring buoy had previously broken loose from its chain. The workboat was dragging a grappling hook along the ocean floor near the platform in approximately 100 feet of water when it snagged the pipeline bundle. Believing they had snagged the anchor and anchor chain, the workboat personnel continued to pull, lifting the bundle off the seafloor. The oil emulsion pipeline subsequently ruptured at a welded area on the pipeline riser beneath the platform causing a significant spill.
This accident, along with others similar in nature, has come to the attention of the the Bureau. The Bureau recommends the following practices and procedures to prevent a recurrence of this type of accident:
- Before placing anything in the water or down on the ocean floor, whether in the vicinity of a platform or in the open ocean, all efforts should be made to ensure that pipeline and power cable locations are known and avoided. In the event work which has the potential to damage pipelines and power cables needs to be conducted, the additional safety margin provided by diver or remote operated vehicle (ROV) assistance should be considered.
- Make sure all company and contractor personnel working on the platform or involved in the handling of equipment to/from a vessel are aware of pipeline and power cable locations in relation to the platform.
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