Research on oil rim volume change in a condensate gas reservoir with high carbon dioxide

Abstract

ABSTRACT At present, the petroleum industry is still at the exploratory stage on how to judge the volume of the oil rim in condensate gas reservoirs. It is unclear how the volume of oil rim will change during the formation of reservoirs, especially for condensate gas reservoirs with high CO2 content in the gas cap. In order to research on this problem, this article first makes two assumptions: first, the reservoir is acylindrical container;second, CO2 will completely extract crude oil, regardless of the intermediate state. On the basis of assumptions, in the PVTsim software, the system of crude oil-CO2 is obtained by fitting the fluid PVT experiment, and then the single factor analysis method is used to explore the influence of temperature, pressure and CO2 on the oil rim and other parameters. Under conditions of L reservoir, simulation result shows the volume decreases by 5.7% to 6.0% with a10% CO2 content increase in the gas cap and the presence of CH4 will reduce the extraction effect of CO2, with an average increase of 10%, the volume of the oil rim increases by 7.2% to 7.6%. In addition, the volume of the oil rim decreases as the temperature increases, and first increases and then decreases as the pressure increases in high CO2 condition. The above simulation results indicate the effect of different reservoir conditions on the oil rim volume of condensate gas reservoirs with high CO2, providing atheoretical basis and guidance for the efficient development of condensate gas reservoirs at sea.