Abstract: Condensate dropout is widely existent in development of condensate gas pool, usually different from gas inflow performance. The theoretical study and field application indicate that big error will occur when predicting condensate gas performance by just using dry natural gas or converting method for the reason that the influence of retrograde condensed liquid on relative permeability of condensate oil and gas is normally ignored. This paper establishes the prediction method for inflow performance of condensate gas well under condition of pseudosteady state by using the theory of condensate gas phase state and flashing method, with consideration of changes of fluid phase behavior and composition as well as skin factor of condensate gas well, along with consideration of the influence of capillary number effect on relative permeability of condensate oil and gas system by using steady state theory and two phase pseudo-pressure functions. The case study shows that the equation for two phase pseudosteady state inflow performance with consideration of capillary number effect can be helpful to properly estimate the productivity of a condensate gas well and correctly recognize the behavior of a condensate gas pool through weakening the effect of retrograde condensation.

Key words: condensate gas well, inflow performance, capillary number, phase state