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Pacific Energy hopes to drill down to oil in first well at Corsair
Pacific Energy Resources hopes to drill for oil in its Corsair prospect in Alaska’s Cook Inlet, company Chairman and CEO Vladimir Katic told Petroleum News Feb. 13. It all depends on when the company can bring a jack-up rig to the inlet and how that timing relates to the drilling season — if the rig were to reach Alaska by May or June the company would drill a well into the potential oil reservoirs. If, on the other hand, the rig were to arrive in September, there would only be time to drill a gas well, Katic said.
“It all depends when the jack-up arrives,” he said.
Gas is thought to exist in the prospect in the Beluga and Sterling formations. Those formations lie in the higher part of the stratigraphic section, thus requiring perhaps an 8,000-foot well to test for gas. Any oil in the prospect would likely be reservoired in the Tyonek and Hemlock formations, below the likely gas reservoirs — testing those deeper formations would require a well several thousand feet longer and, thus, more time consuming to drill than a gas well.
Earlier oil emphasis In 2003, prior to unitization of Corsair, Forest Oil, the company that then owned the Corsair leases, had emphasized the oil potential of the prospect. The company said Corsair might contain 137 million barrels of oil, with 79 million barrels in the Tyonek and 58 million barrels in the Hemlock. Both Forest officials and Katic have since talked about the possibility of 200 million barrels of oil in the prospect, which lies in the same geologic structure as both the East Kitchen prospect and the Northern Lights prospect in the inlet to the north. Northern Lights contains a known oil pool.
The North Cook Inlet gas field also lies on that same structure. Seismic data suggests the existence of natural gas at Corsair – in 2003 Forest estimated as much as 480 billion cubic feet.
Forest’s five-year development plan for the 10,185-acre Corsair unit only envisaged drilling for gas — the initial plan of exploration describes “plans to explore and develop the Sterling-Beluga interval” using a jack-up rig, with a well drilled by Dec. 31, 2008. Favorable drilling results would result in “extended testing to confirm the presence of gas in commercial quantities.”
Why gas? We can only speculate on the reasons for the shift in Forest’s interests from oil to gas. A gas well would clearly be quicker and cheaper to drill than an oil well, and there is strong need for additional gas reserves to supply the Southcentral Alaska gas market. A deep wildcat oil well would also likely prove to be a more risky venture than a gas well.
Since Pacific Energy bought out Forest’s Cook Inlet assets in 2007, Pacific Energy has not added oil drilling to the Corsair plan of exploration filed with Alaska’s Division of Oil and Gas — drilling for oil would require an amendment to that plan, the division has told Petroleum News. However, with Pacific Energy unable to meet the commitment that Forest had made to complete a jack-up rig contract by Dec. 31, 2007, the company has had to negotiate an extension to the drilling timeline with the division. Pacific Energy must now furnish evidence of a jack-up rig contract by April 1, with a well to be drilled in Corsair by June 30, 2009, six months later than the original deadline for Forest.
It seems that the question of whether an initial well will drill deep enough to test for oil depends on when exactly the jack-up rig arrives in the Inlet.
—Alan Bailey
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