Optimization of gas recycling technique in development of gas-condensate fields

Purpose. The research purpose is to increase the efficiency of development of gas condensate fields with a high condensate yield in the reservoir gas and to develop optimal ways of increasing their hydrocarbon recovery. Methods. The effectiveness of the implementation of reservoir pressure maintenance technologies using dry gas for the development of gas condensate fields with a high condensate yield in the reservoir gas is studied on the basis of a heterogeneous 3D model using the Schlumberger Eclipse and Petrel software packages. The technological indicators of the development of gas-condensate reservoir are studied for different pressure values at the beginning of the dry gas injection. Calculations were made for pressures at the beginning of injection at the level of: 1.0 Рinit; 0.8 Рinit; 0.6 Рinit; 0.4 Рinit; 0.2 Рinit. Findings. It has been determined that when the dry gas is injected into a gas-condensate reservoir, reservoir pressure is maintained at a significantly higher level than it is in the case of depletion. This ensures stable operation of production wells over a longer period of the reservoir development. According to the research results, it should be noted that in the case of implementation of the reservoir pressure maintenance technology, a part of the precipitated condensate is transferred to the gas phase, which makes it necessary to extract it together with the reservoir gas. Based on the modeling results, the ultimate condensate recovery factor have been calculated. The calculation results indicate that in the case of the cycling process implementation, the ultimate condensate recovery factor of the gas-condensate reservoir increases by 7.26% compared to depletion development. Originality. Based on the calculation data analysis, the optimal pressure value at the beginning of dry gas injection into a gas-condensate reservoir has been determined, which is 0.842 Рinit. Practical implications. The use of the conducted research results will optimize the development system of gas-condensate fields with high initial condensate yield in the reservoir gas and increase the efficiency of development the explored hydrocarbon reserves in the conditions of a significant shortage of hydrocarbon raw materials in Ukraine. The conducted research results indicate the high technological efficiency of the reservoir pressure maintenance technology using dry gas.