Oil-source correlation study in northeastern Alaska

The occurrence of numerous oil-stained outcrops across the coastal plain of the Arctic National Wildlife Refuge (ANWR) in northeastern Alaska indicates that commercial hydrocarbons could be present in the subsurface of this region. In addition, this region is flanked by two important oil provinces-the Prudhoe Bay area to the west and the Mackenzie delta to the east. To begin to understand the petroleum resource potential of ANWR, we evaluated the source rock quality and thermal maturity of five rock units ranging in age from Triassic to early Tertiary: Shublik Formation, Kingak Shale, pebble shale unit, Hue Shale and Canning Shale. We also compared ANWR oils using stable carbon isotope ratios, tricyclic terpane ratios, and saturate/aromatic hydrocarbon ratios. The organic carbon content of the five rock units range from an average of 1.6 to 4.0 wt%. Cretaceous rocks from the coastal plain are thermally immature (vitrinite reflectance <0.5%) and in the southern mountains thermally mature to overmature (vitrinite reflectance 1.0-1.8%). In general, type III organic matter predominates in the Kingak Shale, pebble shale unit, and Canning Shale, and types II and III in the Hue Shale. ANWR oils are divided into three groups: (1) Jago oil type, includes oils from Angun Point, Katakturuk River and Jago River; (2) Manning oil type, from Manning Point near the coast of the Beaufort Sea; and (3) Kavik oil type, from Kavik west of the Canning River. None of the three oil types of ANWR compares favorably with the economically important oils from Prudhoe Bay and the National Petroleum Reserve of Alaska (NPRA). The most promising source rock for the otherd ANWR oil types could not be type II units of the Hue Shale. Possible source rocks for the other ANWR oil types could not be established. ?? 1986.