THE PHASE EQUILIBRIUM OF THE OIL-GAS SYSTEM IN THE POROUS MEDIA
ZHANG Mao-lin (Southwest Petroleum Institute, Nanchong Sichuan 637001, China), MEI Hai-yan,LI Min,et al.
The oil-gas system and the porous media are interaction system. The three phases of vapor, liquid and solid (rock) will co-exist in the porous media when the pressure is under the saturation pressure. Since the pore radius is very tiny in the porous media, the capillary pressure should be considered. The phase equilibrium calculation model concerning capillary pressure is established in this paper. The capillary pressure, the saturation pressure, and the liquid content of the constant compositional expansion are calculated by using this model for one black oil reservoir, one volatile oil reservoir and two gas condensate reservoirs. The conclusion of the capillary pressure effect on the oil-gas system is summerized at the end of this paper.