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 the wet tundra below (this volume has been revised – see “Current Activities”).
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. The leak is at a location other than the oiled insulation site first observed, and at least one other anomaly site shows evidence of minor oil seepage. BPXA has since initiated a voluntary shut down of Prudhoe Bay’s Eastern Operating Area 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.
The oil leak stopped on August 8, 2006. The leak location, along with several other anomaly locations that exhibited minor signs of oil seepage, have been patched. All 16 significant anomaly sites on the FS2 transit line were slated for securing with bolt-on steel clamps; nine of the 10 bolt-on clamps intended to secure all 16 significant anomaly locations (several anomalies are grouped together) have been installed to date. The transit line remains nearly full and blocked in with a vacuum on each end.
Mechanical oil removal activities using skimmers and direct-suction methods ended on August 13, 2006. Vegetation burning using propane weed burners to remove residual oil from the impacted tundra was tested on a limited scale on August 13 and began as a full-scale effort on August 14. As of August 21, 2006, vegetation burning was approximately 60% complete. Up to eight burner units are being used at a time. Burning activities have been interrupted recently due to interfering rain and snow.
BPXA has issued a final oil-released-to-tundra volume of 23 bbl (966 gal.). This volume is based on reconciling all liquids collected from the tundra through mechanical recovery efforts as well as an estimate of the oil quantity remaining adhered to the tundra, now being remediated through burning. Over 555 bbl of liquids, mostly water, was collected from the tundra during recovery efforts. These fluids, as well as the 176 bbl/7,397 gallons of crude oil recovered directly from the leaking pipeline via folding tanks placed underneath, have been recycled through oilfield process systems.
BPXA stood-down their Incident Management Team on August 12, 2006 and is working under a project mode to complete remaining incident-related tasks. Response operations switched from 24-hours to daytime work only on August 14, 2006.
The START member on-scene since August 7, 2006 demobilized from Prudhoe Bay on August 12. ADEC representatives have also demobilized from Prudhoe Bay.
Freeze protection and corrosion inhibition operations to protect oilfield infrastucture during the shutdown are mostly complete.
Anomaly sites will continue to be monitored by BPXA for any change in status.
Installation of the last of the bolt-on clamps is expected to be completed by the end of August 2006, at which point all 16 significant anomaly sites will be secured with clamps. BPXA will next de-inventory the FS2 pipeline. A de-inventory plan is under development and hot tap locations have been selected. USDOT personnel are involved in reviewing this plan. De-inventorying is expected to occur in September 2006.
Vegetation burning is expected to be completed by the end of August 2006. In conjunction with ADEC, BPXA has developed a plan for sampling the tundra area to determine cleanup attainment in accordance with ADEC standards. It is expected that cleanup confirmation sampling will follow immediately after burning activities are completed.
BPXA will implement a tundra cleanup sampling plan under ADEC consultation and will secure the site from wildlife access, install drainage controls, and establish a monitoring schedule as necessary. Installation of the remaining bolt-on clamp and de-inventorying of the FS2 pipeline will be conducted.
EPA will continue to monitor the incident progress from Anchorage but may return to the site as necessary.
Shut-down of the EOA of Prudhoe Bay has been achieved - oil production in the EOA has ceased and equipment remains de-activated or in an idle mode. The Western Operating Area remains in operation. BPXA is currently planning for the replacement of crude oil transit lines in Prudhoe Bay, including the FS2 pipeline. BPXA will continue to assess the transit line to evaluate the corrosion damage as well as determine requirements for resuming EOA oil production. A time estimate of the resumption of EOA oil production is not available.
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