MOWATT, THOMAS C., and ARTHUR C. BANET, Jr., U. S. Bureau of Land Management, Anchorage, AK

ABSTRACT: Petrography of Selected Aurora Well Samples, Beufort Sea, Northeast Alaska

Cuttings samples from the recently released AURORA 089 No. 1OCS-Y-0943 well, offshore of the ANWR 1002 area of northeast Alaska, provide important information pertinent to possible reservoirs in this area. Petrographic descriptions are of thin sections made from cuttings samples through the major sandstone units.

The middle Brookian sequence, Oruktalik Unit (log unit IV: 14,680-14,860 feet) is Paleocene age. It consists of interbedded sandstone and shale. Oruktalik sands are fine to coarse-grained chert litharenites, with some pebble conglomerate. Chert fragments are typically black or white and sub-angular, regardless of size. These sands are mostly friable with traces of tan dolomitic or siliceous cement.

The Tapkaurak Unit, (log Unit II: 17,325-16,446 feet) is part of the breakup sequence. The Tapkaurak sand is a massive sandstone (16,620-16,446 feet). It is fine to coarse-grained, and comprised of subrounded to subangular predominantly clear to white quartz grains. There are subordinate to trace amounts of igneous rock fragments and black chert and minor amounts of tan dolomitic cement.

There are substantial lithological differences between the Oruktalik and Tapkaurak sands. However, the petrographical descriptions show that both have diagenetic relationships suggesting that they be considered possible reservoirs in the 1002 area.

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