ИСТИНА

At the present time, the search and exploration of oil and gas fields are concentrated in the Arctic region. Exploration maturity of the Arctic shelf is extremely low because of the difficult geological conditions and economic costs. Basin modeling was carried out in 5 regional profiles for assess the hydrocarbon potential of the North Kara, South-Kara and Laptev Sea basins. Various approaches to the modeling and analysis of hydrocarbon systems in basins have been used, because the studied regions are characterized by different data completeness. The history of evolution for the North Kara basin was studied more in detail in view of the lack of calibration data. Both regional and local unconformity were taken into account in modeling. As a result, it was possible to establish that in the basin, the Middle Paleozoic and Mesozoic source rocks are in the oil window. Process of hydrocarbon accumulation in the North Kara basin began in the Middle Carboniferous time. Stratigraphic deposits in the carbonate rocks of the Serpukhov age were formed at the beginning of the Middle Triassic epoch. However, most of the deposits were destroyed after large-scale erosion in the Middle-Late Triassic time. At present, oil accumulations in the Lower Carboniferous rocks, as well as Permian and Jurassic sand deposits in anticlinal-type traps are predicted. The South Kara basin has been studied in the more detail. Based on the results of the simulation, significant oil saturation was obtained in the sandstones of clinoform complex of the Berriasian Age and in the sandstones of the Middle Jurassic. Gas deposits in the Cenomanian and Albian sediments have a mixed nature, and gas is generated both by Cretaceous and Jurassic source rocks. The Laptev Sea basin has a low degree of study, so the elements of the hydrocarbon systems in the region were identified by analogy with the Yenisei-Khatanga basin. The Vendian and Cambrian source rocks here generate gas, and the remaining source rocks are an oil window. Modeling showed that the main oil and gas deposits can be predicted in the Cretaceous sandstones in tectonic traps and in Permian sandstones in anticlinal traps. Meso-Cenozoic source rocks of the Laptev Sea basin are gas-prone (III type), and more mature Paleozoic source rocks with II organic matter type are in the gas window. Thus, the basin modeling method allows to significantly reduce geological risks during prospecting operations within the Arctic shelf.