New Petroleum Kitchen Discovery in the Southern Part of the West Siberian Basin

Comprehensive lithological and geochemical studies were conducted on the core samples from three wells located in the southern periphery of the West Siberian Petroleum Basin (northern part of the Omsk region). These studies enabled the identification and detailed characterization of the main source rocks in the area, as well as the assessment of potential hydrocarbon generation volumes within the study area. The organic-rich siliceous mudstones of the Bazhenov Formation, along with coals and carbonaceous shales of the Vasyugan and Tyumen Formations, were identified as the main source rocks. A detailed analysis of the well sections revealed that the generation potential of the Bazhenov Formation is associated with the Type II/IIS kerogen, which is characterized by early generation and a higher initial hydrogen index. The coals and carbonaceous shales of the Vasyugan and Tyumen Formations were determined to possess oil-generating potential due to the anomalously high content of liptinite macerals in the organic matter (OM) composition. The studies of the molecular and isotopic compositions of rock extracts from both source rock and reservoir rock intervals, as well as the gas sample from the field, confirm that the fluids across the area are derived from marine OM of the Bazhenov Formation and the carbonaceous matter of the Vasyugan and Tyumen Formations, as well as their mixtures. The obtained results demonstrate the presence of an early generation petroleum kitchen in the area studied. These findings contribute to a new understanding of the hydrocarbon prospectivity of the region. The study also highlights the necessity for 3D basin modeling to reassess the hydrocarbon resources and their localization within the southern periphery of the West Siberian Petroleum Basin.