EXTRACTION OF THE RESIDUAL GAS DEPLETED GAS RESERVOIRS NITROGEN INJECTION

The relevance and feasibility of extracting residual gas from depleted gas deposits is shown. The possible directions of the extraction of residual gas from depleted gas deposits by its displacement from a porous medium of non-hydrocarbon gases are characterized. The use of nitrogen to displace natural gas from a porous medium has been substantiated. Using the GEM compositional modeling module, which is included in the licensed computer program CMG (Computer Modeling Group), studies were made of the effect of the pressure of the start of injection of nitrogen into the reservoir and the duration of its injection period on the gas recovery coefficient for residual gau. The study was conducted for deposits of square and round shape. The research results are presented in the form of graphical dependencies of the current reservoir pressure, nitrogen content in borehole products and gas recovery coefficient for residual gas from the pressure of the start of injection of nitrogen into the reservoir and the duration of the period of its injection. Using the results of the research, the optimal values ​​of the parameters of the process of injecting nitrogen into the exhausted gas deposits of square and round forms and the corresponding values ​​of the gas recovery coefficient were established. For the considered deposits of square and rounded forms, they are 0.29 Рin and 14.8 months, 0.31 Рin and 12.9 months, respectively. At the time of reaching the volumetric nitrogen content in the producing gas of 5 %, the gas recovery coefficient for residual gas for a square-shaped deposit is 83.91 %, for a round-shaped deposit – 77.49 %. The physical nature of the process of displacing residual gas with nitrogen from depleted gas deposits of square and round forms is characterized.