Effect of Injected Gas type on Condensate Recovery of Gas Reservoirs Using 3D Compositional Modeling

Abstract

Production from gas condensate reservoirs has a big challenge which is condensate drop out in the reservoir pores when the reservoir pressure drops below the dew point pressure. This condensate accumulation around the wellbore reduces the productivity of the wellbore. Gas recycling is a famous enhanced production methodology to maximize condensate recovery of gas reservoirs. In this study, a three-dimensional (3D) compositional model is used to study the effect of injected gas type on condensate recovery for gas reservoirs with different quality and gas with a wide range of condensate yield. Three types of gases; nitrogen (N2), carbon dioxide (CO2) and dry gases are used as injected gas. The model was produced through five wells under depletion process as base case then apply gas injection with CO2, N2 and dry gas individually. Crestal injection pattern was performed with vertical well as injector and four vertical producing wells in down dip of the reservoir. Based on the research result, for low quality reservoir, N2, CO2 or dry gas injection have higher condensate recovery than depletion case and have nearly the same effect on condensate recovery for different gas condensate yields. While for mid and high-quality reservoirs, N2 and dry gas injection have higher condensate recovery than CO2 and depletion cases. Also, the summary results show that the optimum injection gas type is dry gas due to it has highest condensate recovery, lower cost, operation impact and easily available for covered different reservoir quality and gas condensate yields in this study.