Influence of salt accumulation conditions on catagenesis of subsalt deposits in the Pre-Caspian basin

UDK: 553.982.234

DOI: 10.24887/0028-2448-2025-5-49-53

Key words: Pre-Caspian basin, salt complex, catagenetic transformation, basin modeling

Authors: O.A. Emelianenko (Gubkin University, RF, Moscow); M.T. Delengov (BGT RUS LLС, RF, Moscow); S.F. Khafizov (Gubkin University, RF, Moscow); M.L. Makhnutina (BGT RUS LLС, RF, Moscow); K.I. Dantsova (Gubkin University, RF, Moscow); A.S. Kurushina (Gubkin University, RF, Moscow)

Salt formations have a significant impact on the temperature distribution within the sedimentary cover of oil and gas basins. Having a high thermal conductivity, salts have a cooling effect on subsalt deposits thereby increasing the depth of catagenesis. In addition, evaporite layers are subject to visco-plastic flow, which leads to the formation of large salt diapirs in some parts of the basin and zones without halogen deposits in others. Therefore, when constructing a basin model, it is important to correctly reproduce all the stages of formation of salt sediments, as well as their subsequent transformations caused by the salt tectonics. The Early Permian salt deposits of the Pre-Caspian basin act as one of the leading factors in the formation of the territory's oil and gas potential. Currently, there is no consensus on the conditions for the formation of such a large thickness salt layer. Some scientists claim the accumulation of salt in a deep-sea basin as a result of the penetration of highly mineralized solutions into a semi-isolated basin within the Pre-Caspian depression. Others suggest sedimentation in a shallow basin at the bottom of the depression. Different water depths during the formation of salt deposits imply different temperatures and sedimentation pressures, which in turn can affect the hydrocarbon systems operating in the Pre-Caspian basin. In this work, the authors attempted to model various scenarios for the formation of the Early Permian complex and compare the results of the catagenetic maturity of subsalt source rocks.

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