Gas content of the Upper Cenomanian deposits in Western Siberia

Abstract

The Kuznetsov (Turonian-Lower Coniacian), Lower Berezov (Middle Coniacian-Santonian), Upper Berezov (Campanian), and Gankino (Upper Campa-nian-Maastrichtian) seismic complexes are part of the Upper Cretaceous (except Ce-nomanian) deposits in Western Siberia. These seismic complexes are located from the bottomup, and each of them is of interest as a potential oil and gas bearing horizon. This article represents the conceptual structure and short stratigraphic and lithofacial characteristics of all four seismic complexes. Within identified oil and gas bearing horizons we have mapped the reservoir distribution limits due to either reser-voir claying or regional cap rock sanding. In addition, we have constructed the structure maps of the seismic complexes based on regional seismic works and well data. The detailed structure model has allowed updating the contours of the previously identified positive structures, and identifying the new prospective structures in the Kuznetsov formation, Lower Berezov and Upper Berezov subformations, and Gankino formation. The study of the cryolithic zone and the gas hydrates formation conditions within the territory of Western Siberia has enabled the gas hydrate stability zones mapping. We have accomplished the assessment of the resources for all discovered prospective structures.