To investigate the effectiveness of technologies for the secondary production of hydrocarbons by injecting nonhydrocarbon gases into productive reservoirs, a study has been carried out using the Schlumberger’s prime hydrodynamic simulation tools –Eclipse and Petrel. On the basis of a live geological and technological model of the Hadiach oil and gas condensate field, an investigation has been made of the process of injecting carbon dioxide into the reservoir of the V-16 horizon in order to slow down the flow of formation water into gas-saturated intervals and displace residual natural gas reserves. Based on the results of modeling the development of the V-16 horizon of the Hadiach oil and gas condensate field, a high technological efficiency of carbon dioxide injection at the gas-water contact boundary has been established. When injecting carbon dioxide, the formation pressure in the reservoir is maintained at a higher level compared to depletion development, which leads to an increase in condensate production. The high solubility of carbon dioxide in formation fluids increases the mobility of condensate that has already fallen out in the formation, and at the same time reduces the mobility of formation water. Due to the high displacing properties of carbon dioxide, a high efficiency of its use as an injection agent is manifested in order to control the flow of formation water into productive reservoirs and increase the final hydrocarbon recovery factor. The expected gas recovery factor at the time of the breakthrough of carbon dioxide into the last of the producing wells increases by 3,22 % in terms of residual gas reserves, while the condensate recovery factor increases by 1,29 %. The practical implementation of systems for optimizing the development of hydrocarbon fields under such conditions will increase their production capabilities and, accordingly, increase the final coefficients of hydrocarbon recovery factor