• 标题：A hybrid fracture-micropore network model for multiphysics gas flow in coal
• 关键词：Coal seam gas,Digital core,Micropores,Coal matrix,Coal fracture network,Diffusion
• 作者：Yu Jing, Arash Rabbanib, Ryan T. Armstrong, Junjian Wang, Peyman Mostaghimi

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Coal is not only a combustible black sedimentary rock, but also a source and reservoir rock for natural gas, known as coal seam gas (CSG). A thorough understanding of gas transport through coal matrix micropores as well as coal cleats is of signifificance in both mining and CSG industries. Multiple physical mechanisms are identifified during gas flflow in coal. However, there is not a comprehensive modelling framework, where multiscale flflow behaviours with multiphysics are coupled. In this paper, we develop a hybrid Fracture-MicroPore Network Model (FM-PNM), coupling viscous gas flflow in fractures and gas diffffusion in coal matrix. This model includes multiphysics gas flflow mechanisms in coal, including gas sorption, diffffusion, slip flflow, and compressibility. With FM-PNM, methane flflowing through fractured coal is simulated to compute apparent permeability and gas flflow rates, which are critical for CSG developments. Besides, the process of gas emission from coal over time is simulated, where desorption curves are obtained and analysed at difffferent scenarios. This multiphysics FM-PNM gives a promising framework for studying gas flflow in fractured coal, which can be integrated with other works to study difffferent coal internal structures, flflow models and stress conditions. This model has a wide range of applications, including prediction of greenhouse gas (GHG) emission of coal mines, ventilation design during mining, CSG development, and CO2 storage management.