At approximately 1400 hours ADT on August 6, 2006, Region 10 Phone Duty Officer (PDO) Matt Carr received notification from BP Exploration (Alaska) (BPXA) of a leak from a 30-inch diameter, elevated, crude oil transit line located between Flow Station 2 (FS2) and Flow Station 1 (FS1) within the Eastern Operating Area (EOA) of the Prudhoe Bay oilfield. BPXA reported that 4 to 5 bbls (168 - 210 gallons) of crude oil was released to wet tundra below.
The cause of the leak is under investigation. Pipeline integrity data collected from "smart pig" operations in July 2006, released in a preliminary report obtained on Friday, August 4, 2006, revealed 16 significant anomalies at 12 locations along this pipeline. These anomalies are associated with corrosion-related pipeline wall thinning. On August 6, 2006, upon observing oil-stained insulation at one of the anomaly locations (but no active leak), BPXA shut down the FS2 facility that fed this pipeline and closed off the FS2 transit pipeline at the source (FS2) and receiving (FS1) ends. This pipeline leak was discovered on August 6, 2006 shortly after the FS2 facility shutdown, at a location other than the oiled insulation site first observed. At least one other anomaly site shows evidence of minor oil seepage. BPXA has since initiated a voluntary shut down all Prudhoe Bay oil production work due to concerns posed by the current oil leak and related pipeline integrity issues as well as those posed a larger crude oil spill from the nearby GC2 transit pipeline in March, 2006.
Weather conditions are overcast skies with light winds. Daytime temperature is approximately 50 degrees F.
Response operations contine 24-hours. The leak of oil from the FS2 transit line stopped on its own at approximately 0400 hours on August 8, 2006. Oil leaking from the pipeline prior to then was caught in folding tanks placed underneath the pipeline, and the contained oil was recovered by vacuum truck. Rope-mop skimmers remain in use in the impacted tundra area to remove oil from the marshy surface. The released oil has impacted an estimated 6,200-square foot tundra area. Two vacuum trucks have been assisting in the recovery operations, and plywood walkways were placed in the spill area to protect tundra from foot traffic damage. The transit line remains blocked in with a vacuum on each end.
The leak stoppage will allow workers to remove the outer insulation layer in the vicinity of the leak in order to identify the leak point. Once identified, the leak point will be secured with a patch, and later, a welded sleeve. Insulation removal is planned to begin the night of August 8, 2006. Recovery efforts were suspended during the August 8 dayshift as preparation for insulation removal and source control began. Recovery volumes as of 1800 hours August 8 are 235 bbls of oil/water mixture recovered from the tundra's water surface and 197 bbls of oil recovered in the folding tanks up until the leak stoppage early on August 8. The original vacuum trucks recovering these liquids have been moved from the site to the nearby FS2 facility for off-loading of collected material into holding tanks, and new vacuum trucks will be taking their place on-site. No disposal of collected materials has occurred yet.
Due to concerns over the integrity of the other areas of weakness detected during the smart pig run, BPXA is installing patches over the 16 significant anomaly locations, to be followed by the welding of sleeves over those locations. Folding tanks have also been placed underneath each location as a precaution. Patch installation began the night of August 7, 2006, and sleeves began arriving in Prudhoe Bay beginning on August 8, 2006. As of August 8, four anomaly sites have been exposed and patched, but patching of the remaining anomaly sites is being suspended while the uncovering and securing of the leak point takes place. The patch and sleeve installations are not intended as permanent repairs but rather for temporary pipeline stabilization as a source control measure.
Freeze protection and corrosion inhibition operations are underway to protect oilfield infrastucture during the shutdown.
Fluids removed from the tundra area (oil/water mixture) will be stored separately from the crude oil recovered directly from the pipeline leak.
Insulation removal will occur at the leak site to allow for identification and patching of the leak point. Further assessment of the transit line to evaluate the corrosion damage is still to be conducted. Patch installation at the other significant anomaly sites will continue and will be eventually followed by metal sleeve installation.
As a result of the FS2 transit pipeline inspection data and associated oil release, BPXA is in the process of shutting down the Prudhoe Bay oilfield, beginning first with the EOA. The EOA shutdown is expected to be completed within the next 7 days. Shutdown of the Western Operating Area will then follow.
START and ADEC representatives will remain in Prudhoe Bay to monitor spill cleanup progress, discuss operational procedures with BPXA response planning and management personnel, and observe site cleanup operations.
BPXA will continue planning for upcoming response-related activities that include the de-inventorying the FS2 transit line, conducting collected material volume assessment and disposal, and final tundra cleanup actions.
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