Effects of Nanoscale Pore Confinement on CO2 Enhanced Oil Recovery in Tight Oil Reservoirs

Kai Zhang


This study shows that effects of nanoscale pore confinement help to suppress the bubble point pressure and decrease a solution gas-oil ratio and an oil formation volume factor. Effects of nanoscale pores drive the vapor and liquid phase composition close to each other. Effects of nanoscale pore confinement can impair multi-component dispersion and improve vaporizing and condensing drive efficiency during CO2 displacement, which contributes to a lower CO2  MMP. A CO2  near-miscible process is more suitable than miscible flooding in tight oil reservoirs, especially with existence of nanoscale pores.