Suprasalt sequence of south-western part of Caspian petroleum province - an important reserve for petroleum resource base replenishment in the Republic of Kalmykia

Analysis of the resource base of the Republic of Kalmykia demonstrates a high petroleum potential of the Caspian part of the region, while the degree of its exploration maturity is extremely low. In the near future, an important role in replenishing the resource base of the republic’s oil and gas sector is assigned to suprasalt sequence, as it is the most accessible for exploitation. Integrated geological and geophysical studies in the Khaptagaisky area of the Sarpinsky trough (2D CDP seismics, near-field transient EM sounding, and basin modelling) allowed creating a model of geological structure of the suprasalt sequence, identifying and delineating zones of oil and gas accumulation. The main feature of the suprasalt sequence structure that is determined by salt-dome tectogenesis made a basis for identification of oil and gas accumulation zones. It is proposed to consider salt-dome structures (salt dome, salt ridge, salt massif) and adjacent slopes of between-dome basins as zones of oil and gas accumulation in suprasalt deposits; they are independent petroleum systems within which the processes of generation, migration (including inflow from subsalt deposits), and accumulation of hydrocarbons occurs. On the basis of conducted structural imaging over the main reflectors, the local oil and gas promising objects (hydrocarbon traps of different types) were identified within oil and gas accumulation zones, and localized oil and gas resources are estimated. The most promising oil and gas accumulation zones are recommended as priority objects for licensing in the course of prospecting and appraisal works