The state of Alaska will implement its own new regulations on North Slope pipeline integrity to supplement new rules being developed by federal pipeline regulators, the director of the state's oil spill prevention division said Sept. 15.
"Even with the new federal rules there are gaps in regulatory coverage of the North Slope field pipelines, and our intent is to cover what the feds won't," said division director Larry Dietrick. "The flow lines from the wells to the processing centers have been a primary concern for us because they carry natural gas with high concentrations of carbon dioxide as well as hydrogen sulfide, which can contribute to corrosion."
The flow lines are smaller in diameter and liquids move at a higher velocity, which tends to limit corrosion, than is the case of the oil transit lines downstream of the processing center, where the corrosion was discovered.
In a related development, BP submitted an application Sept. 13 to the U.S. Department of Transportation seeking permission to restart production in the eastern Prudhoe area so that maintenance and "smart" inspection pigs can be operated in the pipelines.
The U.S. Office of Pipeline Safety is extending its rules governing low-pressure oil pipelines to those in rural areas in response to recent oil spills and corrosion problems in Prudhoe Bay field pipelines operated by BP.
However, Alaska officials said the new federal rules will only cover the pipelines from crude oil processing centers to the entry point to a common carrier pipeline. The new state regulations, which will be in effect by the end of 2006, will govern inspection and maintenance of flow lines from producing wells to the processing centers, where the raw gas, produced water and solids are separated from the oil, Dietrick said.
The flow lines, like the oil transit pipelines to the large common carrier pipelines, are now unregulated, he said. The state has been working on its new rules for two years. They were out for public review at the time of the March 22 oil spill on a Prudhoe Bay pipeline.
Mechanical integrity of the producing wells are regulated by the Alaska Oil and Gas Conservation Commission, which has regulated oil and gas production in Alaska since the 1950s.
BP is continuing to inspect pipelines in the eastern and western sides of the Prudhoe field, said company spokesman Daren Beaudo. BP has found no loss of pipeline metal due to corrosion greater than 32 percent of wall thickness in field pipelines inspected so far in the Prudhoe field aside from two heavily damaged pipelines where oil spills occurred and where corrosion-caused metal loss was greater than 70 percent.
BP believes these pipelines could be operated safely until they are replaced with new pipe this winter, but federal regulators must approve any restart, Beaudo said.
As of Sept. 13, the company had completed inspections on 7,000 feet of 25,301 feet of its western-side Prudhoe pipelines and found no wall metal loss greater than 32 percent discovered so far, Beaudo said.
About 18,000 feet of inspections have been carried out on eastern side pipelines, of 25,996 feet of total pipe, with no metal loss found so far greater than 30 percent, he said.
Inspections are being carried out with ultra-sonic U-T technology and two new systems, Electromagnetic Acoustic Tranducer and Low Frequency Eddy Current technology, Beaudo said.
The western side of Prudhoe Bay is continuing in production but the eastern side remains shut down. BP hopes to restart at least part of the eastern side, if federal regulators agree, after cleaning and running smart pig inspections in pipelines. The company hopes to have bypass connection links in place by the end of October to use the undamaged Lisburne and Endicott field pipelines to begin production from Flow Station 2 in the eastern side of Prudhoe and Gathering Center 3 on the western side, according to Maureen Johnson, BP's manager for Prudhoe Bay. GC-3 is now linked to eastern side pipelines.
Tim Bradner can be reached at tim.bradner@alaskajournal.com.
