TY  - EJOU
AU  - Liang, Zeliang 
AU  - Tan, Jia 
AU  - She, Jiachao 
AU  - Wang, Fengnian 
AU  - Wang, Yi 
AU  - Li, Donghao 
AU  - Duan, Rugang 
AU  - Chu, Haotian 

TI  - Regulation of Critical Capillary Number: High-Efficiency Displacement Mechanism of Deep Coalbed Methane Considering Wettability Heterogeneity of Proppants between Fractures
T2  - Frontiers in Heat and Mass Transfer

PY  - 
VL  - 
IS  - 
SN  - 2151-8629

AB  - Significant wettability differences between proppants and coal matrices in deep coal reservoirs limit gas–water mass transfer, a key factor for coalbed methane recovery. This study develops a hybrid wettability fracture model using <i>in-situ</i> data, coupling Navier–Stokes equations with a phase-field method to simulate multi-scale gas–water flow. A random wettability mapping technique captures spatial heterogeneity. The critical capillary number (<i>Ca</i>)-balancing capillary and viscous forces-serves as the key threshold governing flow pathways. At low <i>Ca</i>, capillary forces dominate, causing liquid film aggregation and gas blockage; at high <i>Ca</i>, viscous forces break films and open pathways. Wettability gradients drive asynchronous phase transitions through force competition, dynamically reconstructing flow paths. We propose an optimized strategy: operating near the critical <i>Ca</i> breaks confined liquid phases, while a hydrophilic-hydrophobic balanced system enables synergistic film pre-reconstruction and secondary breakage to maximize gas transfer efficiency. This work clarifies how critical <i>Ca</i> regulates flow via wettability heterogeneity, providing a theoretical and optimization framework for enhanced mass transfer in porous media relevant to energy applications.
KW  - Heterogeneous wettability; gas-water two-phase flow; capillary number; seepage path regulation

DO  - 10.32604/fhmt.2026.078050