The chemical kinetic models are widely applied to study the organic matter evolution in sedimentary rocks during catagenesis. Such models are used to reconstruct the dynamics and spatial position of main zones of hydrocarbon generation in sedimentary basins. The process of hydrocarbon formation is represented as a series of parallel independent reactions or it is studied through analysis of evolution of chemical composition of organic matter. The scales of catagenesis, reflecting spatial changes in the intensity of gaseous and liquid hydrocarbon generation are developed. Of interest is the comparison of these approaches by the example of well-known Mesozoic deposits in West Siberia, for which one of the most substantiated scales of catagenesis zoning is developed. Four samples from the Urnenskaya and Kamennaya areas were studied. The samples were treated with chloroform and then were pyrolyzed at linearly increasing temperature at an average rate of 24.45 K/s. The one-stage model with independent reactions of first order was used to calculate kinetic parameters and to simulate catagenesis zonation. It was assumed that the frequency factor is constant for all reactions and distribution of initial components by activation energy is governed by the Gauss law. The calculations of spatial positions of the main zone of hydrocarbon generation were made using three values of temperature gradient of 30, 40 and 50 K/km. The range of intensive generation is 1.5 to 4.5 km, which corresponds to the place of main zone of gas and oil formation for the Mesozoic deposits of West Siberia and does not include deep zone of gas generation. Probably it results from multiple stages of the actual process of hydrocarbon generation and the formation of intermediate, thermally more stable components, leading to the expansion of a actual range of intensive hydrocarbon generation.
