PETERS, KEN E.¹ and FRANK J. PICHA^2
1Mobil Technology Company, Dallas, TX
²Chevron Overseas Petroleum Inc., San Ramon, CA

Abstract: Age-Related Biomarkers Identify Jurassic, Paleogene, and Mixed Oils from the Carpathian Region, Czech Republic

Biomarker analyses indicate that five crude oils in the Vienna basin, Carpathian thrust belt, and the European foreland plate in Moravia originated from Jurassic and Paleogene source rocks. Oils from the Lubna-18 and Dolni-Lomna-1 wells are genetically related based on similar geochemical compositions. These oils show high oleanane and 24-nordiacholestane ratios, age-related biomarker ratios that are consistent with an origin from Paleogene organic-rich rocks. These rocks are inferred to be either the Menilitic shales of the Carpathian thrust belt or autochthonous Paleogene deposits buried below the thrust belt. Oils from the Zdanice-7 and Damborice-16 wells correlate geochemically with extracts from Jurassic source rocks in the Sedlec-1 and Nemcicky-1 wells. Like the extracts, these oils lack oleanane and show low 24-nordiacholestane ratios, supporting an origin from Jurassic organic-rich marls. Oil from the Tynec-34 well in the Vienna basin appears to be a mixture based on oleanane, 24-nordiacholestane and other ratios that fall between the above two groups of oils.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas