Study on the phase characteristics and thermodynamic properties of CO2 containing associated gas

Abstract

Focusing on the typical mixed system formed by combining oilfield-associated gas and CO2 during the CO2 flooding process, the PR equation is used as the theoretical model basis for the phase characteristics and physical properties of carbon dioxide. The influence of C1–C3 low-carbon hydrocarbons on the phase envelope, density, and sound velocity of carbon dioxide is analyzed. The results indicate that, in the case studied here, C1 has the greatest impact on the phase characteristics of carbon dioxide. The research findings can provide a reference for the identification of CO2 phase states containing associated gas and the control of operating pressure.