On the basis of long-term geological and geophysical studies and exploration wells drilling, the possibility to discover oil deposits in the Lower Cretaceous and Jurassic sediments of the Gulf of Ob in the Kara Sea is substantiated. On the territory of the Yamal-Nenets autonomous district, including the Ob and Taz Gulfs, several large deposits of hydrocarbons were discovered. The most studied is the middle part of the Gulf of Ob where gas-condensate fields in Cretaceous deposits are discovered. Perspective oil-gas complexes of the Jurassic and Neocomian age are characterized by the presence of continuous impermeable beds. These beds separate the allocated productive series. The production potential is confirmed by the results of on-shore deposits testing. To date, the reservoir properties of the Cretaceous sediments of the Ob and Taz Gulfs deposits have been studied in sufficient detail. However, there is no data on reservoir properties for sediments of the so-called “lower structural floor”, primarily for the Jurassic formations and, even more so, for the Paleozoic sediments. An important factor affecting the reservoirs properties is the presence of zones of abnormally high reservoir pressures observed in the entire thickness of the on-shore Jurassic sediments, starting with the Bazhenov formation. The results of testing of large on-shore deposits located on both sides of the Gulf of Ob (Parusovoye, Novoportovskoye etc.) showed that oil deposits is present in both the Neocomian and Jurassic sediments. It is confirmed by the opening and commercial operation of the Yarudeyskoye oil-gas-condensate field. Geochemical studies of the source strata, the degree of their catagenetic transformation, as well as a detailed analysis of the properties and composition of hydrocarbon fluids of the Lower-Middle Jurassic and pre-Jurassic sediments of the Northern part of the West Siberian petroleum basin showed the possibility of the presence of oil deposits in the Jurassic offshore sediments which are not yet studied by drilling. The current task is to identify new deep-seated anticlinal structures that can be commercial gas and oil reservoir.
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