A total of 9 oils and 15 rock samples from the National Petroleum Reserve, Alaska (NPRA), have been characterized and analyzed using a variety of organic geochemical techniques by a number of laboratories involved in a multidisciplinary study of these samples. Results presented in this paper will concentrate on two aspects of the study. The first is the determination of biological marker distributions (i.e., steranes and triterpanes) in both the oils and the rock samples using the technique of gas chromatography-mass spectrometry; the second is characterization of the organic matter in rock samples using microscale pyrolysis techniques combined with gas chromatography and gas chromatography-mass spectrometry.

Sterane and triterpane fingerprints of the 9 oils permit them to be divided into two main groups. The distributions of steranes and triterpanes in the core samples show that some of these samples can be eliminated as source rocks on a maturity basis. Other cores have distributions of steranes and triterpanes that are sufficiently different from the oils to eliminate them as possible sources for the oils examined in this study. Detailed characterization of organic-rich rocks, or source rocks, by pyrolysis-gas chromatography and pyrolysis-gas chromatography-mass spectrometry allowed distinctions to be made between the rocks on the basis of their source material and, in certain cases, their relative maturities.