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THE ROLE OF POSTSEDIMENTATION TRANSFORMATIONS IN THE FORMATION OF THE SANDSTONE RESERVOIR PROPERTIES OF THE PARFENOVO PRODUCING HORIZON OF THE ANGARO-LENSKOYE FIELD (EAST SIBERIA)

D. S. Goryaynov, I. V. Varaksina, I. G. Zakiryanov

Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia

Detailed lithological studies of the Parfenovo Horizon of the Angaro-Lenskoye field located in the south of the Siberian Platform have been carried out. It is shown that sedimentation conditions influenced further postsedimentation changes in productive sediments. It has been determined that sand reservoirs are characterized by a diverse complex of newly formed minerals and structures, indicating transformations up to the stage of late catagenesis and superimposed processes. The influence of each secondary process on the formation of void space is considered and it is concluded that as a result of the deep postsedimentation transformation, the primary reservoir properties of sandstones have generally become worse. Compaction and formation of secondary cements played a negative role, while leaching had a positive effect. The minimum values of reservoir porosity and permeability are observed in the most compacted, well-sorted sandstones of distal bars and fine-grained deposits of prodeltа. The best reservoir properties are possessed by less sorted sandstones of deltaic distribution channels, where residual vugginess has been preserved, contributi ng to leaching.

Keywords: Siberian Platform, Angara-Lena step, Vendian, terrigenous deposits, Parfenovo Horizon, stadial analysis.

DOI 10.20403/2078-0575-2025-2-60-69

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