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DEC: Pipeline corrosion rates drop steadily, are at lowest level in 12 years
Kristen Nelson PNA Editor-in-Chief
North Slope pipeline corrosion levels for 2001 were at their lowest in 12 years, the Alaska Department of Environmental Conservation reported in late March when it released its second annual report on the environmental commitments made by BP Exploration (Alaska) Inc. and ARCO as part of the Charter for Development of the Alaskan North Slope, the agreement which led to state support of the BP-ARCO merger.
Phillips Petroleum Co. assumed responsibility, along with BP, for fulfilling charter obligations when it bought ARCO Alaska Inc.
The 10-year charter commitments monitored by DEC include: $10 million to clean up abandoned sites; cleanup of abandoned drums; cleanup of BP and Phillips contaminated sites; closure of inactive reserve pits; North Slope spill response — support of independent professional spill response organization and $2 million in Arctic spill response research and development; corrosion monitoring; conversion to double-hulled tankers; up to $500,000 a year for additional work at the discretion of the commissioner. On schedule DEC Commissioner Michele Brown said she believes “we are still on schedule in meeting the charter’s goals.”
Brown said highlights of 2001 included arrival at Valdez of Phillips’ first new double-hulled vessel, the Polar Endeavour; BP and Phillips cleaned up and disposed of almost 1,000 hazardous abandoned drums; cleanup of eight abandoned contaminated sites on the North Slope is well under way.
“I commend BP and Phillips for these milestones, even as I stress the need for continued diligence by both industry and the state,” she said.
Corrosion commitment The pipeline corrosion monitoring commitment requires Phillips and BP, in consultation with DEC, to “develop a performance management program for corrosion monitoring and related practices to prevent leaks and structural failures in the North Slope pipelines operated by each company.”
Consultation sessions with DEC are required twice a year to review monitoring, maintenance and inspection practices.
DEC said BP and Phillips have “conducted an extensive corrosion control and management program.” The agency hired an independent technical expert to review BP’s and Phillips’ pipeline corrosion programs and to recommend improvements.
“DEC’s review concluded that overall pipeline corrosion rates have been steadily decreasing since 1993 and were at their lowest levels in 12 years,” the agency said. While internal corrosion rates increased slightly in 2000 in some production lines and produced water injection systems, DEC said the companies have taken corrective steps. Inspection priority DEC said the “review also concluded that external corrosion is a significant risk to pipeline integrity and additional resources may be needed to control it.”
The agency said that external corrosion risk has been identified at pipeline weld-pack locations, where segments are welded together and wrapped with field-applied insulation. That insulation, DEC said, is “susceptible to moisture entry, increasing the risk of corrosion.”
The companies have put a priority on inspecting weld-pack areas “that may be at highest risk or are located where greater environmental damage from a leak would occur,” DEC said. BP has inspected 70,000 of 185,000 weld locations at Greater Prudhoe Bay. “Based upon the observed rate of corrosion damage,” DEC said, “BP has committed to more than double its rate of inspections in these areas for 2002.”
Phillips has inspected 67,000 of more than 101,000 weld locations. Although Phillips is ahead of schedule on its weld-pack inspections, it “will also double the inspection rate for below-grade well packs,” DEC said, and will complete initial screening of all significant road crossings by the end of the year.
The companies estimate they will spend $55 million on corrosion programs in 2002.
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