Oil Groups in the East Mediterranean Continental Margin and Onshore, Israel

Shimon Feinstein, Zeev Aizenshtat, Irena Miloslavsky, Moshe Goldberg, and Mark Obermagher

Saturate and aromatic hydrocarbon molecular characteristics and δ¹³C data obtained from oil samples from producing wells and oil shows in the eastern Mediterranean continental margin and onshore Israel show clear clustering into five different genetic groups. The clustering is concordant with their geographic distribution, namely, the inland Dead Sea, Meged and Coastal Plain groups, and the continental margin Yam and Mango groups. Differences in samples composition within groups are mainly confined to the light-end n-alkane and monoaromatic compounds whereas heavier alkanes and aromatic parameters show consistent correlation. Hence the differences observed are attributed to selective post-generational modification, mainly by biodegradation and perhaps some water washing. The clear distinction in biomarker characteristics between samples from different groups, and consistent similarity within each group, including thermal maturity levels, suggest that each genetic group represents a single source rock and generation kitchen. Furthermore, differences in biomarker characteristics and δ¹³C in the saturated and aromatic fractions suggest that the Dead Sea, Meged and Coastal Plain oil samples were all generated from different marine carbonate-rich source rocks. The offshore Mango oil was generated from a clastic source rock, probably with an input of some terrestrial organic matter. Biomakers and aromatic compound ratios of the continental margin Yam oil reveal distinctly different and more mature oil, but the source rock and depositional environment signals are somewhat ambiguous. These results imply that there had been generation of mature oil from at least five different active source rocks in different subterrains of the eastern margin of the east Mediterranean basin.

AAPG Search and Discovery Article #90161©2013 AAPG European Regional Conference, Barcelona, Spain, 8-10 April 2013