The objective of this study was to investigate the effects of the development degree of carbonate dissolved pores and gas injection velocity on the gas-water two-phase seepage. An interparticle-dissolved dual-pore network model was proposed using a convolution algorithm by considering the characteristics of carbonate karst pores. The proposed unsteady-state gas-water seepage model took the effects of gas compressibility and pore-scale pressure propagation into account, and it was validated by comparing the simulation results with the core-derived gas-water two-phase seepage through unsteady-state gas flooding experiments, which comprehensively characterizes the pore-scale gas-water seepage flow in pore-scale modeling. The gas flooding procedure at different injection velocity was simulated by assuming different characteristics of dissolved pores in carbonates. The results indicated that the more developed dissolved pores can bring about a wider gas-water two-phase infiltration area and a longer gas-water co-flow period. Further, the competitive balancing between the gas injection pressure and the capillary and viscous forces could also impact gas sweeping efficiency, resulting in different gas-water spatial distributions, gas injection velocity and pressures. The results provided a deep technical and theoretical view of the gas production in carbonate reservoirs, which has important significance for improving the exploitation efficiency of carbonate reservoirs.
YANG Xin, LI Xingfu, TANG Yanbing, DAI Juncheng, QI Tao, LI Min, LIU Xu. Investigation of gas flooding dynamics in carbonate using an interparticle-dissolved dual-pore network model. Natural Gas Geoscience[J], 2023, 34(6): 973-979 doi:10.11764/j.issn.1672-1926.2023.02.007
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