Following North Slope Crude: from the ground to the gas station.

• Author: Hollander, Zaz
• Position: Special section: OIL & GAS

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Think of the flow of Alaska crude oil like a tree, with North Slope pipelines as branches feeding into the 800-mile-long trunk that is the trans-Alaska oil pipeline. Now turn that tree upside down, so the North Slope pipelines become roots and the oil-laden tankers departing Valdez become branches. Where do those branches lead?

Our refined crude may end up at gas pumps in the Northwest, California, Nevada or Arizona. It may fuel jets at airports in Seattle, Los Angeles and Portland. It may stay right here, flowing into pickups or F-16s.

It also ends up in some curious places, like that can of soda on your desk. Calcined petroleum coke, used to make aluminum, may be the most valuable product--by weight--made from Alaska North Slope crude oil.

Conversely, the crude used by Alaska's oil refiners these days may not even come from Alaska. North Slope production is declining. Alaska's oil supply from the North Slope peaked at 2.1 million barrels per day in 1988. An average of about 609,000 barrels of oil flowed through the pipeline to Valdez each day in February. Alaska's crude production can't possibly account for the 3 million barrels a day of refining capacity on the West Coast, where most Alaska oil ends up.

Oil companies operating on the Slope, even those refining here in Alaska, make up the difference at the refinery by purchasing crude on world markets. Petroleum products being sold by Alaska producers, even within our state, may come from other countries altogether. The list is long: Canada, Iraq, the Arab Gulf, Mexico, Argentina, Ecuador, Colombia, Angola, Australia, Russia.

"They either buy crude from others or use their crude from other production areas to fill up that 3 million (barrels) a day," says Joyce Lofgren, a petroleum economist with the Alaska tax division. So even though Alaska accounts for about 11 percent of the nation's domestic crude production, we may be driving around with gas made from a little Russian oil.

THE JOURNEY BEGINS

The bulk of Alaska North Slope crude moves from Prudhoe Bay to Valdez via the trans-Alaska oil pipeline. The 48-inch diameter steel pipeline crosses three mountain ranges and more than 34 major rivers or streams. More than 16 billion barrels have moved through the pipeline since oil began flowing in 1977. Estimates put the total value of Alaska's North Slope oil since 1977 at more than $103 billion.

Alyeska Pipeline Service Co. operates the pipeline for a consortium of...