Home – Home – Jornals – Russian Geology and Geophysics 2004 number 7

Under consideration is geochemistry of Paleozoic oils and oil-producing rocks in southeastern West Siberia. It is shown that the Devonian deposits had a considerable initial potential of hydrocarbons but at present it is largely exhausted. Emphasis is placed upon the genesis of Paleozoic oils. To clarify it, we carried out a molecular-level comparative study of geochemistry of Paleozoic oils (from intra-Paleozoic horizons and petroliferous horizons of the Paleozoic-Mesozoic boundary zone) and dispersed organic matter from the Paleozoic deposits (chiefly, Devonian and Cambrian) and the Mesozoic bottom (Togur and Tyumen' Formations) of the southeastern West Siberian petroliferous province. Using the cluster analysis applied to the same diagnostic set of biomarker parameters, we subdivided the explored oils and bitumens into three families. Comparative analysis revealed genetic relationships between the families of oils and bitumens. It has been shown that the first family of oils and bitumens is genetically related to marine oil- and gas-producing sequences of Late Proterozoic age (cis-Yenisei zone) and Paleozoic age (interior of the West Siberian geosyneclise), the second family is polygenetic, and the third one is of continental genesis and is genetically related to the Lower-Middle Jurassic deposits accumulated in lacustrine, lacustrine-palustrine, and alluvium environments and resting on the Paleozoic deposits.