SIMULATION OF FLOW BEHAVIOR OF GAS CONDENSATE AT LOW INTERFACIAL-TENSION

A vertical, long-core experiment of natural depletion of a gas condens ate that was conducted by Elf Aquitaine is simulated by an equation-of -state (EOS) compositional simulator, UTCOMP. The Peng-Robinson (PR) E OS is used for phase-behavior calculation. Because of low interfacial tension (IFT) in the measurement, more attention is paid to the influe nce of IFT on gas/oil flow behavior. Two different types of model are used to compute the relative permeability. Model I is a Corey-type mod el combined with the capillary number concept. Model II is a modified form of the model proposed by Coats(6). The simulation results indicat e that the effect of low IFT on relative permeability can be reasonabl y described by the two models selected, although the producing gas-oil ratio (GOR) obtained using Model I deviates somewhat from the experim ental values in later depletion stages. The condensed liquid can be a mobile phase at very low liquid saturation, since the IFT is so low th at the capillary force can be neglected. The liquid flows through the porous medium under the control of gravity in this case.