Geochemistry of Biological Marker Compounds Extracted from Sediments and Oils of the Bulge, Northern Alaska and Yukon Territory

BANET, ARTHUR C., JR., U.S. Bureau of Land Management, Anchorage, AK

The North Slope is a major petroleum province with production from sediments ranging in age from upper Mississippian through Cretaceous and noncommercial discoveries in sediments from Proterozoic(?) to Tertiary age. Many oils, seeps, stains, and outcrops are heavily weathered in the Arctic, especially in the Bulge. This severely limits the familiar hydrocarbon-source rock correlations and interpretations based on total organic carbon, pyrolysis data, stable isotopes, and chromatograms of C-15+ extracts. Biological marker compounds such as steranes and triterpanes are present in these extracts in small quantities and are less affected by the severe weathering effects. Despite their horrendous names (both IUPAC and common), gas chromatography-mass spectrometric determined distributions nd ratios of these compounds are useful in determining hydrocarbon-source rock relations.

Ternary plots of C-27, -28, -29 steranes and rearranged steranes show affinities for depositional environments, possible maturity effects, and source rock-extract correlations. Triterpane analyses show similar correlations and compounds unique to certain stratigraphic units. Comparisons of data from the Arctic National Wildlife Refuge, Prudhoe, National Petroleum Reserve-Alaska, and the Yukon-Beaufort indicate the existence of multiple "oil kitchens" in the region generating oil and gas.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)