Based on pyrolytic data (3 995 samples from 208 wells) organic matter types of Bazhenov Formation are identified in the central part of Western Siberian basin. Zones of kerogen types I, II, III and mixed I-II and II-III are mapped. Content of sulfur, paraffins, resins and asphaltenes, viscosity, density, temperature and gas content in oils from Upper Jurassic and Lower Cretaceous sediments (3 806 oil pools) are mapped. Oil gradations are identified and distributed. The alternative model of zones of kerogen II and IIS types is presented. The established distributions of organic matter types can be used in basin modeling and in assessment of oil-and-gas bearing prospects.

Five members were identified and traced in the Bazhenov Formation within the Khanty-Mansi Autonomous Region -Yugra. The members have different macroscopic descriptions, geochemical and mineralogical parameters, and extension areas. For statistically unbiased estimate of geochemical and mineralogical parameters of the formation, the authors suggest using parameter maps generated by formal or contents selection of cross-section intervals. Thickness-based weighted average members identified based on geochemical and mineralogical parameters of the deposits were mapped with and without consideration to boundary conditions. The paper discusses the source potential of the Bazhenov Formation, with outlining extension limits of rocks hosting organic matter of different types. The paper provides data on weighted average key pyrolysis parameters, calculations of organic matter transformation, hydrocarbon generation volumes in the Bazhenov rocks, hydrocarbon volumes in place, correction for loss of gaseous hydrocarbons while lifting core, and residual source potential.

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