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A map of deep heat flow of West Siberia has been compiled on the basis of over 6000 heat flow determinations, and the present temperature field has been analyzed in terms of the role of various factors forming the geothermal regime.
Analysis of local temperature fields in the vicinity of 340 hydrocarbon pools shows that almost 80% of them are associated with considerable heat flow variations, of which some are positive anomalies.

Integral methodology of geological survey, exploration, and production for Russia as a whole is in progress. Criteria for recognition of petroliferous megacomplexes and their basic elements are described. It is demonstrated that oil pools of Jurassic and older deposits are confined to large "hot" fields (regions), whereas gas accumulations exist under more moderate bed temperatures. This regularity is used for predicting oil and gas deposits.

The West Siberian basin formed as a result of the Early Triassic rifting and downwarping of the Earth's crust during the Mesozoic and Cenozoic. Three stages are recognized in this process: early (postrift, Middle Triassic-Middle Jurassic), middle (platform, late Middle Jurassic-Eocene), and late (neotectonic, late Eocene-Quaternary). In this paper, the regularities and conditions of sedimentation are described concisely, and the potential of Lower-Middle Jurassic petroleum-bearing complexes (Zimnii, Sharapov, Nadoyakh, Vym', and Malyshev) and Neocomian cllinoforms is estimated. The conclusion is made that the further increase in reserves of hydrocarbons in the West Siberian petroliferous province in a sufficient volume is possible at the cost of these two petroleum-bearing stories. A program of their further study on a regional scale is proposed. This program will be a base for a more complete estimation of resources of the complexes under study, for determination of areas for detailed seismic prospecting and parametric drilling, and for their geological and economical estimation aimed at a necessary licence.

Based on generalization of 1500 measurements of vitrinite reflectance, deep zoning of organic-matter (OM) catagenesis in Mesozoic deposits has been established, and schemes of catagenesis were constructed for the top and bottom of the Jurassic deposits. The OM catagenesis is within the range of grades PC₃ to MC₃² in the Upper Jurassic deposits and PC₃-AC₃ in the basal Jurassic horizons. Throughout most of the West Siberian megabasin, OM reached the end of mesocatagenesis and apocatagenesis. Regionally, the degree of OM catagenesis of the Jurassic deposits increases from the margins to the central and northern, most buried, areas of the West Siberian megabasin. The level of OM maturity ubiquitously increases with depth, but the rate of these changes varies throughout the area. The highest deep gradient of variations in OM catagenesis was identified in the Yamal and Gydan regions. Depth ranges of the main zone of oil generation (oil window) were determined from vitrinite reflectance values in different petroliferous regions. In the Nadym-Pur region, the main zone of oil generation is identified in the depth range 2.9-3.8 km, in the Pur-Taz region, at 2.8-3.6 km, in the Gydan region, at 2.4-3.3 km, and in the Yamal region, at 2.0-2.8 km. The Jurassic deposits to depths of about 4.0 km have not passed out of the oil window yet and can be of interest for oil and gas exploration. Down the section, the sequences are in the zone of intense gas generation, and, therefore, preservation of only dry and fat gas accumulations is possible at great depths. The same is true for the Triassic and Paleozoic sediments, in which the organic matter underwent significant thermobaric changes (grades MC₃² – AC₃).

The structure, composition, and formation settings of the Callovian-Oxfordian deposits of the Pur-Irtysh, Taz-Kheta, and Silgin facies districts of West Siberia are considered. In the first of them the Callovian-Oxfordian deposits include the Vasyugan and Abalak Formations; in the second, the Tochino and Sigovsk Formations; and in the third, the Naunak Formation. The variability of the Vasyugan Formation in the southeastern areas of the West Siberian Plate, in the latitudinal Ob' region, and in the Nadym-Taz interfluve has been shown by lithological and mineralogy-petrographical studies invoking production geophysics and geochemical and paleontological evidence. This allows recognition of three facies subdistricts: Ob'-Tara, Ob'-Agan, and Nadym-Pur. In addition, the Yamal-Nadym facies subdistrict, where the Abalak Formation occurs, has been recognized.

The opinions about the structure of the Neocomian deposits in West Siberia are discussed. We defend the viewpoint of its clinoform structure. According to studies performed, clinoforms are bodies of transgressive-regressive sedimentation cycles (cyclites) formed during avalanche sedimentation. Their structure involves two types of sand-siltstone reservoirs related to shallow-water shelf and distal fairly deep-water sediments, each containing a wide range of traps. Clinoforms are stratigraphic and petroliferous subdivisions calling for independent complex studies.

The prospects for oil and gas potential of the northern Tunguska syneclise are estimated with regard to quantitative oil-geologic characteristics of Riphean-Paleozoic deposits overlapped by Permian-Triassic basalts. These characteristics have been for the first time obtained for the inner regions of this syneclise. On the basis of spatial combination of the deepest (to 10 km and more) large negative structures of platform cover and adjacent uplifts – potential zones of gas and oil accumulation, – the areas of the most probable formation of large accumulations of hydrocarbons were supposed. Two of them, Upper Khugdyakit and Khantai, have been recommended for top-priority studies by parametric drilling to a depth of up to 3.5 km.

Criteria for predicting the petroleum potential of ancient deposits of complicated structure with a long evolution history of hydrocarbon pools are considered. They rest on combined stratigraphic, tectonic, lithofacies, geochemical, and hydrogeological data. Detailed prediction of petroleum potential has been made for the Vendian-Lower Cambrian subsalt terrigenous and carbonate deposits of the Vilyuchan, Lower Nepa, Upper Nepa, Tira, Lower Danilovo, Upper Danilovo, and Usol'e reservoirs. Fields different in potential, petroliferous zones, and first-order prospecting objects have been recognized in the areas of their occurrence. Predominant types of traps, pool volumes, and phase compositions of hydrocarbons are predicted. The results will add to the efficiency of search for petroleum.

Vendian-Cambrian and Devonian evaporite and salt sequences have been reliably distinguished in the sedimentary cover of the Siberian Platform, the lower part of which controls the economic petroleum potential of Precambrian reservoirs, and the upper one shows good prospects for productivity of subsalt and intersalt beds. In this context it is suggested that evaporate sequences in the Tarim Platform, which occur in Cambrian, Carboniferous, and Paleogene sections, make a subject of a special study in terms of their screening role in order to refine the prospecting guidelines for hydrocarbon pools in the subsalt reservoirs of the Tarim petroleum province.