High oil reserves characterize most fields in Western Siberia. However, along with this, zones of the productive formation that are poorly involved in development and production wells, in which products with a high proportion of water are produced, are distinguished within limits. For understanding the causes of this problem, it is important to consider the material composition of the reservoirs. In particular, it is necessary to consider the clay content, which is associated with the reservoir properties of rocks, hydrophilicity, hydrophobicity and, accordingly, with wettability. The article examined and analyzed a representative sample of core study of two wells in the Gubkinsky oil and gas region, which suggested the possible reasons for the lack of oil reserves.

Oil-water-saturated formations of Western Siberian fields represented by polymictic sandstones are often characterized by strong granulometric heterogeneity. This is the reason for an incorrect assessment of the physicochemical properties of reservoirs, including wettability. On the example of the BS9 - BS11 formations of two fields of Surgut oil and gas region, the distribution of wettability of core samples was analyzed. An analysis of the modeling results for the hydrocarbon phase displacement by oil-saturated reservoir water was carried out using the Tulbovich method. To assess reliability of the wettability values, it was proposed to correlate the difference in the masses of water and kerosene displaced during capillary impregnation and centrifugation with differences in the mass of water and kerosene in water-and kerosene-saturated samples. The method was used to plot the distribution of porosity, permeability and relative clay content on the wettability parameter by capillary impregnation and centrifugal displacement. The results obtained were compared with similar dependences of the reservoir properties and clay content on the general wettability parameter. The type of wettability of core samples with good reservoir properties is validated in complex, low-permeability reservoirs with a high content of clay material. It is recommended to use the results of modeling the displacement by capillary impregnation and centrifugation with differences in the mass of water and kerosene.

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The article discusses the problems of effective application of acid hydraulic fracturing (HF) technologies in carbonate reservoirs. The optimal technology of acid fracturing has been substantiated, adapted to the geological and production conditions of the development of productive deposits and mining equipment of a gas condensate field of the sea shelf. The results of the design and calculation of the predicted flow rate for specific geological and production conditions of candidate wells are presented.