BANNET, ARTHUR C., Jr., U.S. Bureau of Land Management, Anchorage, AK 99516

ABSTRACT: The Aurora well; its impact on the Arctic Wildlife Refugeoil and gas assessment.

The Aurora well is one of the newest and deepest stratigraphic tests on the Alaskan North Slope. Information from this well fills an important gap between the geological databases of Alaska and the Canadian Beaufort. Analysis of the Aurora well logs and geochemical data identifies an entirely clastic sedimentary section which is divided into 14 log units. The three deepest units (18,325-15,937 feet) belong to the Breakup sequence (upper Jurassic-mid Cretaceous). Units IV through XIII (15,937-2,385 feet), are of the middle Brookian sequence (Paleocene-upper Eocene). The upper Brookian sequence (upper Eocene-Pliocene) is the shallowest unit identified, and Tuktoyaktuk sequence (Pliocene and younger) sediments are inferred at this location from regional geologic considerations. The strat graphy of these units suggests that the lower Cretaceous Unconformity has not entirely removed the Prudhoe Bay-equivalent reservoirs from the eastern part of the Arctic coastal plain.

The informally named Tapkaurak sand (Unit II) and the Oruktalik sand (Unit IV) which had a gas show are possible reservoir facies considered in the 1991 Coastal Plain-1002 area analysis. Geochemical data and burial history reconstructions show major differences form earlier analyses across the 1002 area. Also, the thermal maturity data indicate that considerable tectonic activity has taken place in this area. Finally, although indigenous organic carbon analysis are skewed towards poor oil generating potential, the concentration and distribution of C15+ extractable hydrocarbons in the Aurora section suggest the presence of migrated hydrocarbons from uncorellated, but possibly nonmarine sources.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.