Regional distribution patterns of resins and asphaltenes in Western Siberia oils

The paper studies the spatial distribution patterns of resins and asphaltenes in the main regional oils reservoirs of the West Siberian megabasin. The studies on schematic maps for the main regional reservoirs (Lower and Middle Jurassic in general, Upper Jurassic (horizons П, Ю0, Ю1), Neocomian, Aptian-Albian-Cenomanian) show that, from the central regions in the northern, northeastern and southeastern directions, a decrease in the content of resins and asphaltenes in oils is observed. In the central part of Western Siberia, oils with a relatively high content of resins and asphaltenes, formed in deep-sea sediments with hydrogen sulfide contamination, are localized in Jurassic and Cretaceous deposits. In the northern regions of Western Siberia, where less reducing conditions existed in marine sediments and there was a significantly higher level of catagenesis, low-resin, virtually asphaltene-free, light oils are localized in Jurassic and Neocomian deposits. The constructed maps-schemes of distribution of resins and asphaltenes in oils can be used in forecasting the quality of oils, in assessing the prospects of oil and gas potential of the West Siberian megabasin.