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Aging Alaska Oil Pipelines
Mineral of the Month: Boron


Aging Alaska Oil Pipelines

On its way to be reinjected into the wells in the Kuparuk oil field on March 26, a mixture of 111,300 gallons of seawater and crude oil leaked out of a pipeline, befouling 2 acres of snow-covered tundra on Alaska’s North Slope. According to a statement issued by ConocoPhillips, the operator of the service pipeline, and the Alaska Department of Environmental Conservation, corrosion inside the 6-inch-diameter pipe was to blame. This spill is one of many relatively small spills over the years that are causing people to wonder about the condition of Alaska’s aging oil infrastructure.

Carrying oil 800 miles from the wells at Prudhoe Bay, Alaska, south to the port at Valdez, the Trans-Alaska Pipeline traverses three mountain ranges and more than 800 streams and rivers. When it was built in the 1970s, the pipeline was planned to last 30 years. Now some people are concerned about the state of the aging infrastructure. Image copyright Larry Fellows, Arizona Geological Survey.


When oil was first discovered in 1968 in Prudhoe Bay near the northern tip of Alaska, one big issue was how to get the oil to market. Working together, oil companies devised the Trans-Alaska Pipeline System to carry oil from the bay 800 miles south to Valdez. The pipeline took about three years and $8 billion to construct and first began transporting oil in June 1977. Since then, more than 14 billion barrels of oil have moved through the system. The pipeline is 48 inches in diameter, with walls averaging one-half inch thick, and was designed to last 30 years.

Some 28 years later, pipelines of all different sizes, pumping stations, work pads, buildings and access roads have sprung up across the North Slope to support the myriad wells and oil fields. “When you fly over the Brooks Range, the spread of infrastructure really strikes you,” says George Gryc, a retired petroleum geologist with the U.S. Geological Survey, who also served on a National Research Council committee that studied the North Slope (see Geotimes, May 2003). And it’s all aging, he says.

Although, Gryc says, the pipelines have performed “very well over the years,” and are in “pretty good shape,” they “have had and continue to have corrosion problems.” That’s no surprise, he says, with the North Slope’s tough environment. The average annual high temperature at Prudhoe Bay is 18 degrees Fahrenheit, with an average high of well below zero for the winter months. The area receives about 33 inches of snow per year, according to Anchorage Daily News.

Although Alyeska Pipeline Services Company manages the Trans-Alaska Pipeline for the owners, including ConocoPhillips, BP Exploration Alaska and others, the companies themselves operate and manage the pipelines and infrastructure at their own individual fields. To combat corrosion, the companies spend millions of dollars annually on monitoring and refurbishing the steel pipelines.

BP Exploration Alaska, for example, spends more than $100 million annually on maintenance, says Daren Beaudo, a spokesman for the company. BP inspects about 100,000 locations using a variety of inspection methods, from visual observations to ultrasonic testing and “smart pigging,” which involves sending instrumented devices, or “pigs,” through the pipes to detect anomalies, Beaudo says. “The infrastructure has been well-maintained,” he says, “but admittedly was built with a 30-year life in mind.”

Alyeska has a similarly rigorous inspection process for the Trans-Alaska Pipeline, according to the company. They utilize four types of pigs, including one that cleans wax out of the pipeline, one that checks for deformation such as dents or wrinkles, and one that inspects for corrosion or pitting in walls caused by oil or water eating away at the steel pipe. When the pigs find an anomaly, the company determines if there is a problem and fixes it if necessary, says Rhea DoBosh of Alaska’s Joint Pipeline Office in Anchorage, a state and federal coalition of agencies.

A few stretches of pipeline have been entirely replaced over the years, including an 8-mile stretch through the Atigun Floodplain below the Atigun Pass, the highest point through which the pipeline traverses, DoBosh says. After corrosion was identified there in the late 1980s, she says, “there was a lot of concern about corrosion throughout the pipeline.” That concern led to a corrosion settlement agreement with the state of Alaska that specified intense corrosion mitigation activities. “But we’re talking about a few miles of an 800-mile line,” she says, so the fact that other major sections have not had to be replaced is a testament to the “aggressive corrosion mitigation activities” on the part of the companies and the “aggressive oversight” by the Alaskan agencies.

The Alaska Department of Environmental Conservation is one of the primary oversight agencies. When an oil spill occurs, operators first call the department. Every year, it reviews oil spill and leak prevention and contingency plans that are submitted by the oil companies to ensure that the companies are following proper “spill prevention techniques,” according to the department. Those methods include corrosion monitoring, leak detection, tank inspections and pipeline testing.

The U.S. Department of Transportation also inspects the transmission and distribution pipelines at least once a year, says Jon Strawn who works at the department in Alaska. The department will also do as many inspections as necessary to ensure that oil companies are following the extensive federal laws and regulations, including follow-up inspections and special inspections based on incidents or consumer complaints. Oil companies “have to go out and proactively look for problems before they occur,” he says, which is “all part of an integrity management program.”

These efforts are becoming increasingly relevant as the Bush administration pushes ahead with plans to lease parts of the National Petroleum Reserve-Alaska (NPRA) and potentially open the Arctic National Wildlife Refuge (ANWR) to exploration, which would extend the life of North Slope production. “With continued proper maintenance, upkeep and change-outs where appropriate, the infrastructure will last for the foreseeable life of the field,” says Beaudo of BP, which plans to operate on the slope for another 50 years. Taking care of the pipelines and infrastructure, he says, “is a bit like taking care of a late model automobile — it can be kept running perfectly with the proper maintenance and care.”

Megan Sever

Links:
"The drilling footprint on the North Slope," Geotimes, May 2003

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Mineral of the Month: Boron

U.S. Geological Survey Boron Commodity Specialist Phyllis A. Lyday has prepared the following information on boron.

What does boron have to do with baseball, apple pie, motherhood and Chevrolet? Boron minerals and chemicals are used in the tanning of leather baseballs and gloves; in micro-fertilizer to grow apples and in the glass and enamels of bakewares to cook apple pie; in boron detergents for soaking baby clothes and diapers; and in fiberglass parts for the Chevrolet Corvette.

Boron minerals and compounds have been used commercially for 2,000 years. In nature, boron is present in the form of borate, combined with oxygen and other elements. Borates are salts or esters of boric acid, and are widely present in oceans, sedimentary rocks, coal, shale and soils. The modern borate industry began in the 13th century when Marco Polo brought borax, an ore of boron, to Europe to be used in glass and as a flux (a substance used to promote fusion) in metallurgy.

The borate component of importance is boron oxide. The glass-forming properties of boron oxide account for three-quarters of the total U.S. consumption of boron minerals and chemicals (by weight). These applications include manufacture of borosilicate glass, ceramics, frits and insulation-grade and textile-grade glass fibers. The most commonly refined borate, borax pentahydrate, is used in glass and agriculture and is a derivative of anhydrous borax. Borate’s other uses include preservatives in makeup and antiseptics in eyewash and first-aid creams.

Boric acid is produced by adding an acid to boron minerals or borax; the anhydrous boric acid is produced by heating borax to evaporate water. Uses for boric acid include glass and cellulosic insulation. Anhydrous boric acid can react to produce elemental boron, which is used in car airbags.

Other boron compounds also have varied uses. Boron nitride forms cubic crystals that rival the hardness of diamond. Boron carbide, a highly refractory material and one of the hardest substances known, is used as an abrasive and in nuclear shielding.

There are more than 200 known boron-bearing minerals, and they are obtained by several methods: by pumping brines with high boron concentrations from wells to a processing plant to separate the borax by carbonation or solvent extraction; by pumping chemicals underground and processing the dissolved boron solution; and by surface and underground mining.

World production of all boron minerals and compounds in 2004 was about 4.4 million metric tons gross weight of ore. Major producers of boron minerals, in order of importance are Turkey, the United States, Russia and Argentina.

For more information on boron minerals and compounds, visit minerals.usgs.gov/minerals.

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