Energy independence is an important component of sustainable development and security of the state. Ukraine has a great hydrocarbon potential of the subsoil, which is why the priority objective is a search and exploration of new deposits of hydrocarbon raw materials. One of the important directions for increase of potential resources and reserves of oil and gas is the development of large deep (over 4500–5000 m) deposits, as hydrocarbon reserves at small and medium depths are quite depleted in many regions. For a long time, hydrocarbon reservoirs in basement rocks were underestimated during geological exploration works. Obtained results indicate that new concepts of the formation of hydrocarbon deposits can dramatically change the system of oil production, methods of prospecting and development of deposits. It is important to assess possible oil-and-gas-bearing capacity of sediments and rocks of the basement by identifying prospective areas of hydrocarbon deposits, including in the rocks of the crystalline basement. In Ukraine, main prospects of discovery of oil and gas deposits at great depths are associated nowadays with the Dnieper-Donets Rift (DDR). Deposits with accumulations of hydrocarbons at depths of more than 5000 m are concentrated in the main oil-and-gas-bearing areas of the Rift that coincide with the central paraxial and marginal zones of the graben. It was in the central segment of the DDR that the main regularities of oil-and-gas-bearing capacity of deep-lying geological formations were first discovered: secondary nature of reservoirs, discovery of the phenomenon of supercollectors and associated huge debits. It is relevant and promising to study the process of recovery/replenishment of gas reserves by the example of deposits that are at the final stage of development.