GEOCHEMICAL STUDIES OF CRUDE-OIL IN THE G UAFITA FIELD, STATE OF APURE, VENEZUELA

A geochemical study of crude oils from the Guafita oil field, Apure st ate, Venezuela, was undertaken in order to obtain information concerni ng the organic matter that gave origin to them, their degree of maturi ty, the possible source rock that originated them, and the alteration processes that they may have suffered in the reservoir. The concentrat ion of total sulfur, saturated hydrocarbons, aromatic hydrocarbons, re sins and asphaltenes, in these oils, were determined. The distribution of saturated hydrocarbons was determined by gas chromatography. The d istribution of steranes and terpanes (m/z 191 and 217), and aromatic c ompounds (m/z 178, 192, and 198) was determined by mass spectrometry. Results indicate that the crude oils analyzed are paraffinic-naphtheni c, unaltered, and derived predominantly from marine organic matter wit h a small contribution of continental organic matter. These crude oils were generated by a mature, clastic, source rock.