In fluid flow simulations for petroleum and geothermal fractured reservoirs, it is important to well understand gas-liquid two-phase fracture flow characteristics. However, gas-liquid two-phase flow characteristics have been poorly understood due to the lack of studies using real rock fractures under confining pressure. In the present study, gas-liquid relative permeability curves have been investigated through nitrogen-water and steam-water two-phase flow experiments and numerical model simulations for a fracture in granite under confining pressure. Experimental and numerical results for nitrogen-water two-phase flow have revealed that relative permeability curves in this system are characterized by the ν type relative permeability curves, which have been reported for liquid-liquid two-phase flows through fractures under influence of capillarity. The ν type relative permeability curves result from very strong interference between phases due to capillarity in a lognormal-like aperture distribution of a real fracture. With the ν type relative permeability curves, it is unlikely for both phases to flow simultaneously. Furthermore, results for steam-water two-phase flow have revealed that relative permeability curves in this system are also characterized by the ν type relative permeability curves. Although several previous studies have suggested that two-phase flow characteristics can be different between steam-water and nitrogen/air-water systems, due to influences of phase change and a different contact angle. The present study has provided no evidence for them. It has been revealed that relative permeability curves are essentially the same for any pairs of fluids.
Relative Permeability Curves for Gas-Liquid Two-Phase Flows Through Rock Fractures
Kikuchi, Takuma , Watanabe, Noriaki , Sakurai, Keisuke , Ishibashi, Takuya , and Noriyoshi Tsuchiya. "Relative Permeability Curves for Gas-Liquid Two-Phase Flows Through Rock Fractures." Paper presented at the SPWLA 20th Formation Evaluation Symposium of Japan, Chiba, Japan, October 2014.
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