Identification of biomarker compounds in selected Kuwait crude oils

Eighteen crude oils from Kuwait oil fields were analyzed by capillary GC/MS spectroscopy. Thirty-two biomarker compounds, 18 pentacyclic triterpanes a nd 14 steranes were identified and semi-quantitatively determined by select ive ion monitoring (SIM) chromatography, The data obtained were used to cal culate several biomarker indices. Depending on the oil source, the variatio n in the pentacyclic triterpanes distribution is more significant than the variation in the sterane distribution. The C-29 norhopane and C-30 hopanes were the dominating biomarkers in all the crude oils analyzed. The calculat ed biomarker indices indicated that the analyzed oils stem from medium matu re oil reservoirs that have undergone biodegradation, to a certain extent. (C) 1999 Elsevier Science Ltd. All rights reserved.