Recent oil exploration in Alaska is centered in five sedimentary basins: Cook Inlet basin; Arctic (North) Slope province; Bristol Bay basin; Gulf of Alaska province; and Copper River basin. Surface and seismic exploration parties have been active in each, greatest emphasis being in the Cook Inlet basin and the Arctic (North) Slope province.
The oil industry in Alaska during 1965 drilled 19 exploratory wells, resulting in the discovery of 3 oil fields, 3 gas fields, and extensions of 2 oil fields and 1 gas field. The 3 oil discoveries, all under Cook Inlet waters, are Granite Point, Trading Bay, and McArthur River. The gas discoveries are on the upland area of the Cook Inlet basin at Birch Hill, North Fork, and Moquawkie. The Granite Point discovery was extended north more than 3 mi. by subsequent drilling. A discovery was made 6 mi. south of production at Middle Ground Shoal. Gas production at the Cook Inlet field was extended about 2 mi. southwest. Two exploratory wells drilled in 1965-66 on the Arctic (North) Slope were reported non-productive. Two shallow dry exploratory wells were drilled on the north flank of the Copper River basin. Both were unsuccessful.
The first two permanent platforms in Cook Inlet were installed at Middle Ground Shoal oil field during 1965, and development drilling began. A twin 8-mi. crude-oil pipeline was completed connecting the two platforms with an onshore treating facility. This furnished the first outlet for crude oil other than that at the Swanson River field. Contracts were let for 6 additional offshore-drilling and production platforms to be erected during 1966.
The most significant event since the discovery of oil in the Lower Kenai Conglomerate (Hemlock) at Swanson River was the discovery of multiple-pay sandstone beds in the Middle Kenai Formation. These sandstone beds furnish an additional objective and have higher porosity and permeability than the Lower Kenai Conglomerate. Gas pay zones have been found in both the Middle Kenai and Upper Kenai sandstone zones.