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TAPS safety questioned Following January leak, pipeline regulators cite risks, hand Alyeska to-do list Wesley Loy For Petroleum News
The operator of the trans-Alaska oil pipeline expects to make a prompt reply to federal regulators, who on Feb. 1 issued a proposed order to address problems they say could pose a public safety risk.
Michelle Egan, spokeswoman for Alyeska Pipeline Service Co., told Petroleum News on Feb. 14 her company’s reply letter was “in the draft review stage.”
She further said Alyeska is likely to take issue with parts of the eight-page notice it received from the Pipeline and Hazardous Materials Safety Administration, an agency in the U.S. Department of Transportation.
“There are things we don’t agree with,” Egan said. “That’ll be clear in our letter.”
PHMSA issued its “notice of proposed safety order” as fallout from the recent prolonged shutdown of the 800-mile pipeline system due to a crude oil leak at Pump Station 1 on the North Slope.
The leak, discovered on the morning of Jan. 8 in the basement of a booster pump building, forced an initial three-day shutdown of the pipeline and a herculean effort to engineer a makeshift solution.
In its notice, PHMSA proposed a laundry list of “corrective measures” that would appear to involve major work and serious spending along the pipeline, which has been operating since 1977.
The pipeline owners include BP, ConocoPhillips, ExxonMobil, Chevron and Koch Industries.
Multiple risk conditions PHMSA said it conducted “an investigation of the safe operation” of the trans-Alaska pipeline system, or TAPS, including the Pump Station 1 leak.
“As a result of the investigation, it appears that multiple conditions exist on your pipeline facility that pose a pipeline integrity risk to public safety, property or the environment,” the notice to Alyeska said.
The notice focused on the pipeline’s declining throughput — from a peak of more than 2 million barrels per day in 1988 to an average of 600,000 to 700,000 barrels today — and the implications this has for pipeline safety, particularly during a winter shutdown.
“The reduced throughput has resulted in numerous integrity challenges that have not been fully addressed by Alyeska’s operational and maintenance activities,” the PHMSA notice said. “Significant challenges for TAPS future operations include decreasing crude oil temperatures, water freezing due to these decreased temperatures, increased wax precipitation and deposition on the pipe wall, slack line conditions at multiple locations, and changing oil composition.”
Two issues especially need attention, PHMSA said.
First, the current pipeline specification “does not prevent free water and water slugs” from entering the crude stream. The water can lead to corrosion and other problems.
“During a TAPS shutdown in extreme cold temperatures, there is a risk of water accumulation in low points freezing and creating ice plugs which could impede restart of TAPS and damage valves, instrumentation, and other pipeline components,” PHMSA said. “If flowing crude temperature drops below freezing, ice crystals may form in the crude stream, potentially adversely affecting equipment and instrumentation.”
The second issue requiring attention is increased crude oil solids, or wax, adhering to the pipeline wall at lower crude temperatures, inviting corrosion and interfering with pigs — tools that slide through the pipe for testing and cleaning.
Proposed corrective measures The January leak was not from the mainline, 48-inch pipe.
Rather, the leak “appears to be located in the below-ground station piping and headers” between the Pump Station 1 booster pumps and the mainline pumps, PHMSA said.
The piping was manufactured and installed in the 1970s and encased in concrete in the early 1990s, the agency said.
The problem is that this type of “low-flow, dead-leg” piping is susceptible to sediment accumulation and corrosion, and is inaccessible for pigging or external ultrasonic testing, PHMSA said. Corrosion is suspected in the January leak.
Other buried station piping and dead legs exist elsewhere on TAPS and “they similarly cannot be assessed to ensure that there are no pipe integrity threats,” PHMSA said.
Alyeska temporarily restarted the pipeline on Jan. 11, but shut it down again on Jan. 15 so crews could install a 157-foot, above-ground pipe to bypass the problem area at Pump Station 1.
During the event, the minimum pipeline oil temperature Alyeska recorded was 25.7 degrees Fahrenheit, PHMSA said.
The agency is proposing numerous requirements for Alyeska in the safety order:
• Have a third party investigate the Pump Station 1 leak site to determine the cause of the spilled oil. (Alyeska said 317 barrels of oil were recovered from the pump station.)
• Replace any piping along TAPS that can’t be assessed using smart pigs or other technologies. This includes piping that, upon failure, would “interrupt the safe operation” of the pipeline.
• Install an additional permanent pig launcher and receiver between Pump Station 5 and Pump Station 10, and assess the need for more such equipment along the pipeline.
Two cleaning pigs were in transit at the time of the shutdown, but the only receiver available for removing the pigs was at the end of the line at the tanker port in Valdez, PHMSA said. At current throughput rates, it takes about two weeks for a cleaning pig to make the trip from Pump Station 1 to Valdez, and a pig could “cause a plug in the pipeline” in a shutdown and “cold restart” scenario.
Alyeska’s inability to capture or launch pigs at interim locations between Pump Station 4 and Valdez — where the coldest operating temperatures exist and the potential for freezing and waxing is highest — is a “risk condition” on TAPS, the agency said.
• Evaluate the need for increased storage tank capacity at pump stations, especially upstream of Pump Station 1, to handle oil during prolonged pipeline shutdowns.
• Immediately stage cold restart equipment in the field. During the Pump Station 1 leak incident, Alyeska had trouble implementing its cold restart procedures “partially due to the inability to quickly move equipment to the necessary locations along the pipeline,” PHMSA said.
Independent review Egan, the Alyeska spokeswoman, said some of PHMSA’s proposed corrective measures already are in progress.
For example, Det Norske Veritas or DNV, a Norwegian foundation specializing in risk management, is conducting an independent investigation of the Pump Station 1 leak, Egan said.
DNV also is doing a systemwide risk assessment for Alyeska.
“Alyeska already has a risk assessment program,” say internal Alyeska notes provided to Petroleum News. “This project enhances that program by considering risks and barriers from a systemic perspective.”
Alyeska feels it handled the Pump Station 1 incident well, Egan said. No one was seriously injured, hundreds of workers were mobilized in tough weather to deal with the problem, and the leaked oil was fully contained, she said.
“We believe we’re operating the system safely,” Egan said. “It’s a large, complex system. There are risks. We believe we are managing those well.”
But Alyeska has come under considerable scrutiny in recent months. In July 2010, U.S. Sen. Lisa Murkowski, R-Alaska, called for a safety and maintenance review of TAPS because of its importance to Alaska’s economy and U.S. energy security.
Since then, a new president has taken over at Alyeska — Thomas Barrett, a retired U.S. Coast Guard admiral.
Alyeska had 30 days to respond to PHMSA’s notice of proposed safety order. Barrett knows the regulations very well, having previously served as PHMSA administrator.
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