Título: New Insights From the application of Petroleum Source Age Biomarkers to crude oils in the Barinas-Apure Basin, Venezuela

Autor: Olivares, C.; X. Márquez; F. Audemard

Fuente: 8th Latin American Congress on Organic Geochemestry CD-ROM Memorias

Año: 2002

País de publicación: Colombia

Tipo de documento: CD-ROM Memorias

Resumen

This study is part of a large-scale geological project carried on with the purpose of evaluating the Venezuela's petroliferous potential (VIPA 2000). One of the geochemical projects derived, is the application of source age biomarkers to differentiate crude oil families. Results of this study, indicate that the crude oils from the Barinas- Apure Basins might belong to a different petroleum system as previously thought. This paper will focus on understanding the age of the source rock for these crude oils applying source age biomarkers. They allow us to establish a direct link between organic matter type, source rock and the correlative crude oils.

Therefore, two geologic periods marked with important changes in flora and fauna, such as the appearance of new species or the diversification and radiation of others, can be detected through the molecular record. For instance, it is well known the appearance of dinoflagellates in the Triassic and their diversification and radiation into the Tertiary. The organic matter input of these organisms is recorded in the molecular record by 24-norcholestanes (C26 sterane) and 24-nordiacholestanes (Moldowan et al., 1998; Holba et al., 1998). Their ratios (NDR* and NCR*) coupled with other age-diagnostic indicators such as dinosterane and oleanane were used for differentiating age of source and organic facies.

The application of age-specific biomarker provides an interesting case study for investigating the diversity of oils generated from the different petroleum systems and allows a demonstration of the technique to aid in the accurate petroleum system assignments.