The test with the electric induction heater will be done in mid-2009. Roberts said it is aimed partly at testing the heater technique, but also at obtaining uncontaminated samples of the oil for laboratory analysis, Roberts said. Previous batches of heavy oil produced with diesel has been contaminated with the fuel, he said.
Such thermal production techniques to warm the oil are now being used in Alberta to produce heavy oil, BP's West said. One procedure involves injecting steam, with one well drilled to inject the steam and a second drilled nearby to drain oil that is loosened, West said. Companies in Alberta are also using heavy earth-moving equipment to mine very thick, heavy oil that is close to surface.
Surface mining has never been done on the North Slope because the oil is too deep and the surface disturbances would be unacceptable.
The North Slope companies also don't think the steam injection will work because of the amount of energy required to make the steam and the possible problems created as steam is injected through permafrost below the surface on the Slope.
However, thermal heating also requires certain reservoir characteritics to be effective, and while those might be present in some fields on the Slope, they aren't at Milne Point, where BP is operating, West said.
Thermal heating requires good continuity of the reservoir rock so the heat isn't dissipated along fractures or shale barriers in the rock, he said. At Milne Point, the reservoir rock is segmented by shale barriers, which would reduce the effectiveness of thermal heating.
BP's approach is to try to produce the oil without heating. The CHOPS procedure involves producing the oil without heating, and uses a novel production technique that essentially sucks loose sand saturated with the oil up the well with a "progressive cavity pump."
At the surface, oil is separated from the sand-oil mixture. After the oil is extracted, the sand is to be injected back underground in one of the special injection wells BP uses to dispose of drilling mud and cuttings underground.
BP tested the production system in late August and early September at Milne Point, in a well drilled last year at "S Pad" into the Ugnu heavy oil reservoir. The test was concluded Sept. 15 and had better than expected results, BP spokesman Rinehart said.
BP mainly wanted to determine if the sand/oil mix could be produced up the well.
"Our objective was to demonstrate that we can bring the sand (and the oil) to the surface on a sustainable basis," West said.
Rinehart said that did happen, and the test was even more successful because the company was also able to test the oil separation procedure. About 700 barrels of heavy oil, with an API gravity of 10, were extracted from the sand and shipped to the Trans-Alaska Pipeline System, Rinehart said. API gravity is a measure of oil quality derived by the American Petroleum Institute.
"This test was successful in several ways," he said.
