Pyrolysis investigations of organic matter in the rocks are the basis for geochemical characteristics of source rocks and determination of modeling parameters for generation processes in the petroleum basins. Data obtained on Rock-Eval (Vinci Technologies), HAWK (Wildcat Technologies) instruments and other pyrolyzer modifications contains information on amount of organic carbon in the rocks, hydrocarbon generation during thermal history and the maturity of organic matter. The standard interpretation of Rock-Eval pyrolysis data is not suitable for Bazhenov formation in the rocks rich in organic material (amount of organic carbon reaches 20%), which has low porosity and low permeability, and contains a significant amount of adsorbed petroleum hydrocarbons. Pyrolitic peak S
2
contains products of the kerogen cracking, but also it is complicated by the presence of agglomerates which consist of resins, asphaltenes and paraffin-naphthenic hydrocarbons, and subdivides into S
2a and S
2b
peaks before and after extraction (S
2ex). A qualitative characteristics and quantity of liquid and gaseous pyrolitic products estimation by combining pyrolysis, extraction with organic solvents and pyrolysis after extraction for Bazhenov formation of Western Siberia are proposed. Comparison of pyrolysis and chemical-bituminological data for Bazhenov formation allows receiving more accurate information on petroleum generative potential of kerogen and distribution of groups of the hydrocarbon components (where hydrocarbon gases play an important role) in the sedimentary sequence. The ratio of gas, light and heavy petroleum hydrocarbons and heteroatomic compounds are different in the sedimentary sections characterized by different maturity of organic matter. Increasing of organic matter thermal maturity in a range from immature to the end of oil window zone is accompanied by decreasing of the kerogen cracking products from 90 to 10-25%. In extractable compounds the catagenetic maturation shows decrease in proportion of the asphaltenes and increase of light hydrocarbons.
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