Paleotectonic, lithological, geochemical criteria for the oil exploration in the Neocomian deposits, the Uvat region, on the example of the BS<sub>8</sub> formation, the Ust-Balyk suite

Abstract

The Uvat project is one of the exploration projects of PJSC NK-Rosneft in the south of the West Siberian province. The high efficiency was achieved using modern technologies for the interpretation of 3D seismic and the involvement of a full range of well logging in daily work. Now, about 60 % of the territory is covered by 3D seismic surveys, during the period from 2004 to 2021, 27 medium and small fields were discovered, about 250 exploration wells were drilled. Gradually, the volume of the identified resource base is reduced and the urgent task for the "Uvat project" is to replenish it. Based on a comprehensive interpretation of all geological and geophysical materials and many years of experience in geological exploration activities, priority search targets for the territory of the Uvat project have been identified. According to modern estimates, the Neocomian oil and gas complex in the Uvat district accounts for at least 25% of all estimated resources, so it is one of the objects of hydrocarbon growth with potentially oil-bearing traps in the Achimov and offshore formations. The paper analyzes the criteria that had the greatest impact on the oil content of the Sarmanov clinoform reservoir (strata BS8-9). Such an analysis helps to assess not only the risks of hydrocarbon deposits in the BS8 reservoir of the Ust-Balyk suite, but also to adjust the exploration strategy.