Abstract:

For well-test of condensate-gas well, the method of dry-gas well’s single phase pseudo-pressure is continued to use usually. Or the influence of porous media adsorption of condensate-gas and oil is not considered in the procedure of analysis. But many experiments and theoretical studies indicate that porous media adsorption has great influence on the percolation of condensate gas and oil. A mathematical model of transient well-test analysis is developed in this paper on the basis of differential equations of percolation of condensate gas and oil which considered the influence of adsorption. The influence of porous media adsorption is taken into account directly in the model. Approaches of draw down test interpretation are given in multiple outer boundary conditions. The effective permeability of well test analysis will decrease, skin factor will increase, effective leakage radius and controllable reserves of well will decrease too on the condition of reservoir as against the condition of not considering porous media adsorption. These are verified by example studies. For those gas-condensate reservoirs, which heavy hydrocarbon contents are higher and porosities are lower, the influence of porous media adsorption would be more apparent. The researches of this paper indicate that porous media interfacial phenomena have great influence on the laws of gas-condensate reservoirs’ percolation and well-test analysis. The influence can’t be neglected.

Key words: gas-condensate well, draw-down well test, adsorption, two-phase pseudo-pressure