Comparative characteristics of the geological specific features of the subsalt gas-condensate deposits of the Astrakhan dome
The article gives a comparative description of the fields located in the subsalt Paleozoic deposits of the Astrakhan dome. All fields are located within the Astrakhan carbonate platform. The reservoir is made up of different genesis limestones of the Middle Carboniferous Bashkirian stage. There is a similarity and difference of the geological structure of the Astrakhan, Central Astrakhan and Western Astrakhan gas condensate fields. The fields are characterized by a complex structure. They are independent deposits, which are divided into blocks. A significant difference in the position of the gas-water contact within the right-bank part of the Astrakhan, Central Astrakhan and Western Astrakhan gas condensate fields as well as the formation fluid composition may indicate the independence of the deposits. In some researchers’ opinion, the independent deposits can exist in the Astrakhan dome, differing in the gas-water contact position and the content of acidic components in the formation gas. However, the current state of knowledge of the Central Astrakhan and Western Astrakhan gas condensate fields and the right-bank part of the Astrakhan gas condensate field remains extremely low, which is insufficient to develop an unambiguous understanding of the specific features of the structure of the deposits under consideration and to prove the uniformity of the gas-condensate deposit within the entire Astrakhan dome.