Prospects for Oil and Gas Bearing Potential of Paleozoic Basement of West Siberian Sedimentary Basin

One of the most significant and industrially developed oil and gas basins in the world - the West Siberian basin – is characterized by high depletion of large oil fields, well-studied complexes with hydrocarbon accumulations of conventional types, reduction of active residual reserves and significant lack of exploration of complexes with objects of unconventional type, deeply buried, complexly structured and previously technically unavailable for development. Assessment of oil and gas prospects and determination of industrial potential of such object as accumulations in sediments of the contact zone of the Paleozoic basement (pre-Jurassic complex) and Mesozoic sediments of Western Siberia are the most important tasks for increasing the hydrocarbon raw material base in the mid-term perspective. The study directed at identifying the criteria of oil and gas bearing potential of sediments of the Paleozoic basement of West Siberia was carried out on the basis of analyzing the distribution and establishing the main patterns of zones of improved permeability-porosity properties of reservoir rocks analyzed using the lithochemical methods. The geochemical indicators of individual composition of n-alkanes and acyclic isoprenoids of deposits in paleozoic weathering crust and in basal complexes were analyzed. As a result, a conceptual model for the formation of oil and gas deposits within the contact zone of Paleozoic and Mesozoic sediments is proposed. The proposed conceptual model can be used as a basis for geological exploration for oil and gas and will make the choice of new areas more justified.