Thick as molasses: heavy oil development could provide boom to Alaska.

• Author: Liles, Patricia

Imagine owning a piggy bank stuffed with gold coins-$5, $10, even $50 pieces. But the bank's opening is rather small to get the heavy gold coins out. Turning and shaking the piggy bank yields only a few of the smaller, thinner pieces, leaving the heavier, more valuable gold coins locked up.

That's the type of experience that Alaska's North Slope oil producers are facing in developing what could be another Prudhoe Bay-sized oil deposit-billions of barrels of thick, molasses-consistency crude called heavy oil, or its slightly lighter cousin, viscous oil.

Differences of viscous and heavy oil compared to typical light oil can be identified scientifically by several criteria, including density and gravity characteristics of the hydrocarbons. Bottom line-viscous oil is the step in between typical light crude currently being produced on the Slope and heavy oil that is not being produced. Neither viscous nor heavy oil flows easily.

"Light crude is the good, easy oil to produce with the consistency of water, viscous oil found in Schrader Bluff and West Sak is more like maple syrup ... and heavy oil is like molasses," said Daren Beaudo, spokesman for BP Exploration (Alaska) Inc. "Heavy oil is a great opportunity but also a great challenge."

Currently, five North Slope fields are producing about 50,000 barrels of viscous oil per day, according to Blaine Campbell, supervisor, Heavy Oil Development for ConocoPhillips in Alaska. Viscous production comes from ConocoPhillips-operated Tabasco and West Sak fields, and BP's Orion, Polaris and a portion of the Schrader Bluff formation from the Milne Point field, according to Arctic Energy, a North Slope overview booklet published by producers ConocoPhillips and BP Exploration in April 2006.

While amounting to less than 10 percent of today's crude oil production on the North Slope, viscous and heavy oil could be one answer in the future for maintaining product flow in the trans-Alaska oil pipeline system.

"We've identified a huge resource, more than 20 billion barrels in place," Beaudo said. "That's the beauty of Alaska's world class resources-they are huge resources that come in different shapes and sizes."

The amount of viscous and heavy oil on the North Slope could be even larger. U.S. Department of Energy estimates place the heavy oil resource as much as 36 billion barrels of original-oil-in-place in the Ugnu, West Sak and Schrader Bluff formations, surpassing the original-oil-in-place of Prudhoe Bay and Kuparuk combined.

How much more of the viscous oil resource will be tapped remains to be seen, and whether heavy oil will ever be produced is still a question mark for industry. It...