The article examines the geostructural characteristics of the Astrakhan-Kalmyk segment of the Caspian basin based on data from seismic exploration, deep drilling and modern scientific research. The water area of the Northern and Middle Caspian Sea and its immediate land border are one of the most promising areas for identifying new oil and gas fields in southern Russia, according to a set of geographical features. The studied territory covers the southern (Astrakhan-Kalmyk) part of the Caspian Basin. To date, over 350 oil and gas fields have been identified within the North Caucasus-Mangyshlak oil and gas province. The age of productive sediments varies from Paleozoic to Neogene. The main share of initial and projected hydrocarbon (HC) resources is accounted for by the Jurassic, Cretaceous, and Triassic sediment complexes. A two-tiered sedimentary cover is distinguished in the geological structure of the region: a subsalt terrigenous-carbonate Paleozoic basement and a saline-terrigenous Mesozoic-Cenozoic cover. A key role in the formation of the geostructure belongs to the powerful (up to 4-6 km) salt-bearing stratum of the Kungurian stage of the Lower Permian. Special attention is paid to the neotectonic stage of development, which defined the modern structural plan. The Astrakhan part of the depression (Astrakhan Arch) is dominated by high-amplitude structures with high sedimentary thickness, while the Kalmyk part is characterized by a more complex combination of salt uplifts and troughs. The widest stratigraphic range of oil and gas content is typical for the Caspian part of the region, where it covers deposits of the Upper Devonian, Lower and Middle Carboniferous, Triassic, Jurassic, Cretaceous and Paleogene. Unique hydrocarbon traps associated with the Primorsky (Kashagan-Tengiz) carbonate platform have been identified in the Kazakh sector of the Northern Caspian Sea. The traps are a single reservoir covering a complex of sediments from the Famenian stage of the Upper Devonian to the Bashkir stage of the Middle Carboniferous. Certain prospects for oil and gas potential are preserved by the suprasalt deposits of the Caspian Sea, both in the Caspian Sea and on its border.
Duvanova et al. (Thu,) studied this question.