In early March of 2006, approximately 201,000 gallons of oil leaked from the Prudhoe Bay, AK pipeline, making it the largest spill on record in the North Slope region.
In the two months since the spill, BP, Alaska’s Department of Environmental Conservation (DEC) and the U.S. Environmental Protection Agency (EPA) have been working to clean up the spill and ensure the quarter-inch-leak in the 34-inch pipeline is repaired properly. According to reports, the pipeline’s leak detection system failed to identify the leak, but a BP worker driving by smelled oil and sounded the alarm.
BP Press Officer, Daren Beaudo, reported that the leak was temporarily packed within five days of its discovery and a permanent sleeve repair was made shortly thereafter. The line is still shutdown, pending further evaluation.
|Site rehabilitation of the GC-2 oil leak. Photo credit: Unified Command Photo.
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According to Larry Dietrick, Director of Spill Prevention and Response for the DEC, the leak detection system on Gathering Center 2 (GC-2) is not designed to detect that type of leak. “The system can detect a 1% shift of throughput in a 24-hour period. A leak from a quarter-inch hole won’t be picked up by the system.”
Beaudo expressed remorse on behalf of BP over the unauthorized oil release. “We regrettably had a spill and having a spill is unacceptable to us,” Beaudo said. “We will determine if the sensitivity and accuracy of the overall Prudhoe Bay transit line leak detection program can be improved, reducing the number of false alarms and enhancing the ability of the program to detect small leaks of long duration which can lead, over time, to large spills.”
It is believed internal corrosion caused the hole in a buried section of the pipeline, under a caribou crossing, according to On-Scene EPA Coordinator, Carl Lautenberger.
According to Dietrick, as the life-span of an oil field is extended, the water and sediment content in the oil increases. It is these two factors that can accelerate the type of corrosion that occurred in GC-2. “The corrosion management is very sophisticated and the management is continuous to adjust to the changing sediments,” Dietrick said.
Beaudo pointed out that there was possibly a change in the emulsion breaking chemicals that may have increased the rate of corrosion in the line. “One theory is that the emulsion breaker was preventing corrosion inhibitor from carrying over into the line, as well as fostering an increase in bacterial growth in GC-2,” Beaudo said.
Approximately one week after the leak was detected; a second, smaller leak was reported along the pipeline in the North Slope. According to Lautenberger, the report was fully investigated and was found to be not true.
According to Lautenberger, the cleanup is complete and all free liquids were removed within the first two weeks after the spill. Contaminated gravel and most of the vegetative layer in the area was removed and backfill was brought in from the tundra. “We are now getting into the restoration of the area,” Lautenberger said.
BP took the lead on the cleanup with guidance provided by the state and federal governments and has spent approximately $8 million on the cleanup so far. According to state and federal regulations, BP is fully responsible for the oil cleanup and restoration of the area. Lautenberger has commented that the company has been “very cooperative” throughout the process. “This was a good spill response,” Lautenberger said. Dietrick echoed Lautenberger’s comments stating that “the response and cleanup has been outstanding…a level which has become the norm in Alaska.”
Because the spill occurred during some of the harshest winter months, the cleanup was more manageable than if it occurred during a warmer time period. “The ground was frozen, little wildlife was present and the lake was frozen,” Lautenberger said. “If a spill was going to occur, the timing was good.”
The difficulty in the cleanup occurred due to the frigid temperatures of 72 degrees below zero, which limited workers to 20 minute shifts. “This represents a massive effort,” Lautenberger said.
BP will be fined for the spill, but a final penalty has not yet been reached. Generally, the penalty for a spill is based on the spill size, the damage to the environment and the effectiveness of the cleanup project. A fine will be based on a “dollars per barrel” model. The investigation is still ongoing.
Drilling in ANWR
After the Prudhoe Bay spill, discussions became even more heated about the possibility of drilling in the Artic National Wildlife Refuge (ANWR). According to Lautenberger, “there’s a risk there and concern that if it happened in Prudhoe Bay, it can happen in ANWR.”
Dietrick considers the question of drilling in ANWR a non-issue. “It illustrates the ability to respond, contain, control and cleanup an oil spill with minimal environmental impact and no wildlife impacts. This issue has been taken out of context and out of proportion.”
Beaudo pointed out that BP is not engaged in the debate about drilling in ANWR. “That decision is up to the American people and policy makers,” Beaudo said.
About Prudhoe Bay
The Prudhoe Bay field is the largest field in North America. Of the 25 billion barrels originally detected, approximately 13 billion barrels can be recovered with current technology. To date, more than 10 billion barrels of oil have already been produced from Prudhoe Bay. The field is located 650 miles north of Anchorage; 1200 miles from the North Pole and 250 miles from the Artic Circle. The oil at Prudhoe Bay is located in the Sadlerochit formation, a sandstone and gravel area approximately 9,000 feet underground. The average thickness of the oil zone is approximately 60 feet.
Since 1998, five satellite fields have been discovered and developed within the unit boundaries of the oil field. Major investors of Prudhoe Bay, including BP, Exxon and ConocoPhillips Alaska, Inc., have spent $25 billion to develop the field and transport the crude. Approximately 475,000 barrels of oil are pumped each day from the greater Prudhoe Bay region.