New technologies could help slow the corrosion that forced the partial shutdown of Prudhoe Bay, materials science experts say, but the best prevention is improved monitoring. The producer's early estimate at repairs is $170 million. After the current round of emergency work concludes, substantive repairs will begin early next year, a BP spokesman says.
| Workers use ultrasound to scan for |
pipeline's weak areas. (AP/Al Grillo)
Sridhar Seetharaman, a materials science professor at Carnegie Mellon University in Pittsburgh, Pa., says there have been many developments in steel in the last 30 years to make it more resistant to corrosion. "Stainless steel, which is used extensively in maritime applications and in the nuclear industry, doesn't corrode," he says. Manufacturers have found even small amounts of chromium added to steel can slow corrosion. There are galvanizing agents or coatings that can be applied to steel to slow water damage. "There are lots of technologies out there, but not much that's been applied to the class of steel used in a huge pipeline. It tends to be low-end, inexpensive carbon steel," he says. The cheapest option may be to monitor corrosion and repair or replace worn areas, he points out.
But at Prudhoe Bay, the producer's monitoring system did not prevent a major spill this year, nor did it detect extensive corrosion early enough to trigger a phased approach to pipeline repair. BP announced it would stop production at the nation's largest oil field earlier this month after corrosion tests showed pipes were badly damaged. In March, a transit line in the North Slope system, which BP operates on behalf of itself, Conoco-Philips and Exxon Mobil, gushed 201,000 gallons of oil onto the tundra, the North Slope's largest oil spill ever. The spill brought new regulatory scrutiny over the field and resulted in a grand jury to begin investigating BP for possible criminal charges.
Experts say not only have the anti-corrosive properties of steel improved, monitoring technologies are also more advanced than when the field began operation almost three decades ago. Most companies now consider regular use of smart pigs, which employ magnetic fields or ultrasonic technology to detect worn areas, good operating procedure.
Alyeska Pipeline Service Co., which runs the 800-mile Trans Alaska Pipeline System (TAPS) that Prudhoe Bay drains into, operates smart pigs every three years. Its scraper pigs, which remove sediment from pipes, run every week or two. Mike Heatwole, Alyeska's corporate communications manager says the company did not institute major monitoring changes following BP's recent partial closure of Prudhoe Bay, but it did makes changes after BP's March spill. "We're on a cycle to run an instrumentation pig every three years. The next one was scheduled for 2007, but we brought it forward to run it in 2006," he says.
Heatwole says it has partially completed the pigging operation, but is waiting word from BP on amount of oil it expects to be sending through TAPS in the next few months because that will affect the operability of the monitoring device. Heatwole says 60 instrumentation pigs have run through TAPs since the pipeline started operations.
BP officials said they have not recently used smart pigs at Prudhoe Bay because they thought their monitoring system was sufficient.
Arco, the former operator of the eastern side of the field BP now runs, stopped using maintenance pigs in 1992 after TAPs operators were concerned about the large amounts of debris flowing into that system. BP stopped using maintenance pigs in the late 1990s on the Western side of the field.
BP officials now say if they were to do it all again, they would routinely conduct pigging probes. Under orders from federal regulators, BP is increasing inspections on the Western side of the field that continues to operate. The company has promised results from smart pig probes in November.
And the scrutiny on BP continues to increase. House Energy and Commerce Committee Chairman Joe Barton (R-Okla.), recently scheduled a Sept. 7 hearing to focus on BP's shutdown and corrosion problems. He wrote a letter to BP saying, "This latest incident once again calls into question BP's commitment to safety, reliability and responsible stewardship of America's energy resources."
It's been more than a decade since Congress asked the Transportation Dept. to look into regulations to cover low-pressure pipelines such as those blamed for halting Prudhoe Bay's production.
Even now, it's not happening, but Thomas Barrett, administrator for the department's Pipeline and Hazardous Materials Safety Administration, said last week that as a result of the North Slope crisis, the agency was focusing on possible regulations for low-stress pipelines.
Meanwhile, less than a week after BP announced it would shut down Prudhoe Bay, the company said it had secured orders for all 16 miles of pipe it plans to replace, and expects to have the supplies at the North Slope by the end of the year. Mills in Ohio and Texas owned by VM Star and U.S. Steel are among those supplying the steel.
BP spokesman Scott Dean says substantial reconstruction and replacement won't start until next year. "The first quarter of 2007 is what we're looking at," he says.
Dean says it's not yet clear exactly how much the work will cost, but an early and rough estimate is $170 million. BP has not yet said exactly how it might divide costs with ConocoPhillips and Exxon Mobil, which also share ownership of the Prudhoe Bay site.