Hilcorp has sealed a pipeline that had been leaking natural gas in Alaska’s Cook Inlet for several months.
According to Hilcorp, dive crews installed a clamp on the fuel gas line in Middle Ground Shoal last week (13 April), which stopped the release of natural gas from the affected pipeline. Weather and ice conditions allowed divers to begin their work on Saturday, 8 April. A total of 12 dives were completed on the fuel gas line in order to locate the leak, then properly position, stabilize and prepare the pipeline for repair.
The leak point was located on the very bottom of the pipeline, resting on a boulder embedded in the seafloor. Initial visual inspections noted the breach to be approximately 2in in size. The affected section of the line was lifted approximately 1.5ft from the seafloor, then stabilized, allowing for closer, more careful inspection of the leak site.
Divers removed scaling and cleaned the exterior of the line. Exact measurements of the breach were taken, recording the actual size at 3/16in wide and 3/8in in length. After proper cleaning and preparation, a steel and rubber clamp was installed over the leak. The clamp assures a gas tight, liquid tight seal that will reinforce the pipeline.
The repair operation was provided to the Alaska Department of Environmental Conservation and the Pipeline and Hazardous Materials Safety Administration.
Now that the leak has been stopped, over the next several days, as weather permits, further inspection and stabilization of both the oil and gas pipelines in Middle Ground Shoal will be completed. Neither pipeline will be returned to regular service until Hilcorp, along with state and federal regulators, agree it is safe to do so.
The natural gas flowing through the line provides power to four offshore platforms: Baker, Dillon, A & C.
On 7 February, Hilcorp Alaska identified a natural gas leak in Alaska’s Cook Inlet waters. The source is an 8in pipe located at a depth of 80ft of water, and part Hilcorp’s Middle Ground Shoal (MGS) Fuel System. The system consists of approximately 15mi of in-service natural gas pipeline and serves to fuel four existing production platforms.
In February, Hilcorp estimated the leak volume to be about 210,000-310,000 cu ft/d.
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