Evaluation of the gas recycling duration on the hydrocarbon recovery from gas condensate fields

Abstract

Optimization of formation pressure maintenance technologies in the development of gas condensate fields with a high initial content of condensate in the reservoir gas using numerical modelling. A study on the efficiency of dry gas injection for pressure maintenance in gas condensate fields was performed with the help of numerical 3D models. Key technological indicators of the reservoir development were calculated for the dry gas injection period of 12, 24, 36, 48, and 60 months. The results are presented as plots for the parameters in a study. Based on the results of the studies, it was found that the introduction of dry gas injection technology ensures that reservoir pressure is maintained at the highest level compared to the development of gas condensate reservoirs on primary depletion. Due to this, further condensate drop-out in the reservoir is slowed down, and the production of partly already condensed hydrocarbons is ensured by their evaporation into the dry gas injected from the surface. The simulation results indicate that increase in the injection duration period leads to an increase of the cumulative condensate production and hence the final hydrocarbon recovery factor. The heterogeneity of oil and gas deposits, both in terms of area and thickness, significantly affects the efficiency of the developed hydrocarbon enhancement technologies. In order to minimize the negative impact of heterogeneity, it is necessary to conduct additional studies on the conditions of specific reservoirs or fields. The reservoir pressure maintenance technology implementation according to various technological schemes, as well as using various types of injection agents, will significantly intensify the development of depleted gas condensate fields with a high condensate yield. Statistical analysis of the simulation results identified the optimum value of the dry gas injection period into the gas condensate reservoir, which is 34.3 months for the conditions of a given reservoir in the study.