Abstract: The Domanik facies shale represents a critical component of unconventional hydrocarbon resources in the Volga-Ural Basin,Russia. This study systematically explores the geological characteristics, hydrocarbon generation potential, and development prospects of the fine-grained, organic-rich carbonate rocks within the Domanik facies. By integrating stratigraphy, petrology, geochemistry, and reservoir properties with drilling and exploration data, this paper comprehensively evaluates key parameters such as the distribution, thickness, organic mattercontent, and thermal maturity of the Domanik source rocks. The results demonstrate that the Domanik facies predominantly deposited during the Upper Devonian to Lower Carboniferous period. The source rocks are rich in Type II kerogen, with total organic carbon (TOC) content rangeing from 1% to 20%, and thermal maturity (R_o) varying from 0.5% to 1.15%, exhibiting a eastward-increasing trend. The reservoir properties are dominated by intergranular pores, microfractures, and lens-shaped organic matter pores, with a high content of brittle minerals and an average brittleness index of 0.9, which is favorable for hydraulic fracturing. The Domanik source rocks were deposited during the subsidence of the East European Platform and preserved within the Kama-Kinel trough system under anoxic conditions during a regressive phase. The facies exhibits significant potential for unconventional hydrocarbon resources, particularly in the area where source rocks exceed 1,000 meters in burial depths and have a net thicknesses greater than 5 meters. These findings provide a robust theoretical framework to support future exploration and development of unconventional hydrocarbon resources in the Volga-Ural Basin.

Key words: Volga-Urals Basin, Domanik deposits, Unconventional resources, Devonian source rock, Siliceous carbonate rock