This work presents a comprehensive analysis of the geochemical, mineralogical, and petrographical properties combined with bulk kinetics modeling of Domanik rocks from various depths of the Kuzminovsky oilfield in the Volga-Ural Basin, Russia. The study reveals that the Domanik samples have a high content of total organic matter (TOC) of up to 13.31 wt %, and mainly contain Type II kerogen with a slight II/III kerogen type, which indicates very good to excellent oil generation potential. The hydrogen-rich kerogen in the samples is expected to generate paraffin, naphthene, and aromatic (P–N-A) oil with low wax content. The maturity indicators demonstrate that most of the studied Domanik samples have generally reached low thermal maturity stages, defining an immature to moderate-mature oil generation window. The results of the kinetic models suggested that Domanik rocks with vitrinite reflectance (VRo) values in the range of 0.60–0.71% have reached relatively low kerogen transformation ratio, indicating low probability of oil generation. The Domanik samples are characterized by low porosity (up to 3.29%) with a wide range of pore sizes, including interparticle, cavities, cracks, and organic matter pores. The development of these pore types and their quality is mainly controlled by high mineralogical brittleness, i.e., carbonate and quartz, together with high organic matter inputs. Based on the obtained results and observations, the Domanik Formation has a high potential for commercial oil production, which typically requires hydraulic fracturing followed by an in-situ retort, mainly by thermal methods such as steam injection and in-situ combustion processes.

Keywords: Domanik Formation, organic-rich rocks, kinetic modeling, unconventional tight oil, Volga-Ural Basin (Russia)

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