Lithological features of reservoirs within the South Astrakhan uplift zone

A wide range of geological, geophysical and drilling operations has been carried out within the southwestern side zone of the Caspian Basin and its junction with the Karpinsky ridge. To date, no industrial accumulations of oil and gas have been found in the subsalt Paleozoic sediments, therefore, the problem of assessing the prospects for oil and gas potential of subsalt deep-submerged deposits of Devonian and carboniferous remains very relevant for the territory under consideration. Views on the prospects of oil and gas potential, the structure of terrigenous and carbonate complexes, the zones of reservoir development in them and the conditions for the formation of oil and gas deposits remain very contradictory. The comparative characteristics of carbonate massifs with extensive zones of development of terrigenous and terrigenous-carbonate strata are clearly in favor of carbonate differences, the properties of which are more favorable, both in quantitative parameters and in their degree of consistency in area. Occupying a much smaller part of the area of the Caspian Basin, carbonate Paleozoic complexes have concentrated proven reserves of oil, gas and condensate, significantly exceeding the identified reserves in the Terrigenous pre-Tungurian Paleozoic. Deposits confined to the pre-Tungurian Paleozoic terrigenous complexes are characterized by a sharp variability in reservoir properties over an area, as well as their overall low values.