A microfluidic study on the influence of naturally fractured porous media on the phase behavior of condensate gas depletion

There are limited quantitative studies on condensate gas using microfluidics under high-pressure and high-temperature conditions. This study employed microfluidics chips based on real porous media structures to conduct constant volume depletion experiments and investigate the microscopic mechanisms of condensate gas recovery. The aim of the experiments was to reveal the phase-behavior differences between bulk-phase gas and gas contained in porous media. The results revealed that condensate oil recovery in microfluidics experiments was higher than that in PVT cell tests, and nonuniform condensation and evaporation were exclusively observed in the microfluidics experiments. Furthermore, lower pore connectivity resulted in higher depletion recovery, while more developed fractures led to reduced recovery. Specifically, the chip with fewer fractures achieved the highest recovery (71.15 %), whereas the highly fractured chip exhibited the lowest recovery (56.11 %). These findings demonstrate that oil saturation during the process of constant volume depletion (CVD) of gas condensate within porous media is lower than that observed in the PVT cell, thus providing experimental evidence for optimizing condensate gas development in field applications.