The paper examines the verification of existing hypotheses about the structure of thin-layered reservoirs at a number of large deposits of Rosneft Oil Company, located throughout the entire area of Western Siberia. One of the tasks of the work is to verify these ideas about the composition and properties of "clay" elements of textural heterogeneity. Historically, it was believed that clay interlayers inside thin-layered plasto-intersections are interlayers of clays, but later researchers began to express opinions that these interlayers are clined siltstones with a low proportion of pelitic fraction and may contain hydrocarbons. Another important aspect is the degree of uniformity of the sand component of textural heterogeneity, which in classical methods of well logging data interpretation is accepted as homogeneous and isotropic. In addition, textural heterogeneity at some level can significantly affect the anisotropy of permeability, which can significantly affect the processes of vertical migration of hydrocarbons and their accumulation in reservoir rocks. The work analyzes in detail the Vikulov, Achimov, Jurassic deposits and deposits of the Tanopchin formation. The results of unique studies of properties on cubic core samples, non-standard "pieces" from the intervals of thin layering and photo processing are presented. At the same time, these studies are of a massive nature. This allowed us to conclude about the presence of three textural components in reservoir formations: homogeneous coarse and medium-grained sandstone with maximum permeability values for the sample, homogeneous fine-grained sandstones and siltstones, micro-layered clay siltstones. It is shown that such alternation must be taken into account in petrophysical modeling.
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