ExxonMobil in Alaska: Oil find at Gwydyr Bay

On April 4, 1975, Mobil Oil announced a new oil discovery at the “Gwydyr Bay South No. 1 wildcat well located about three miles north of the Prudhoe Bay oil field on Alaska’s North Slope,” on a lease (ADL47468) owned 50-50 with Standard Oil of California, which later became Union Oil, then Unocal, and now is part of Chevron.

Per Mobil’s press release, “Oil flowed on production tests at the rate of 2,300 barrels per day on one-half inch choke from perforations in the Sadlerochit formation. The test was drilled to 12,237 feet.”

Mobil said in its release that it had no reason to believe the new discovery was “another Prudhoe Bay field” and that additional appraisal drilling would be required to determine its size and commercial significance.

That lease was never developed, but today is still held by ExxonMobil and Chevron, and is part of the Beechey Point unit, operated by Brooks Range Development Corp., which has in recent years drilled exploration wells near Mobil’s well to determine the viability of Mobil’s discovery.