Episubsalt deposits of oil and gas in the Caspian Depression

Nowadays we differentiate between subsalt and suprasalt oil and gas reservoirs in the Caspian Basin which is a huge salt-dome basin. It has been found out that a significant portion of past salt reservoirs were formed due to the vertical migration of hydrocarbons from the subsalt sediment complex, namely as a result of the reorganization of subsalt oil accumulations. It is proposed to call this group of deposits “episubsalt”. They can be located throughout the entire suprasalt section. At present their most reliable determination occurs in the process of completing the third stage of studying the oil and gas potential of salt domes in the case of identifying the productivity of “PermoTriassic red rocks” lacking generating abilities. Episubsalt reservoirs indicate the existence of more ancient hydrocarbon accumulations deeper than them and are direct signs of the productivity of the subsalt complex. It is recommended to move on to intensive study of deeply submerged peripheral areas of salt domes which will facilitate the fastest development of hydrocarbon suprasalt and subsalt complexes.