Gas-solid Coupled Model Based on Gas Seepage Characteristics of Drilling Drainage

With the increase of mining depth of mine, ground stress, gas pressure, the influence of factors change such as coal properties on gas seepage is more and more obvious. According to the basic theory of solid deformation and gas seepage characteristics of drilling drainage, the article introduced the control equations of solid mechanics and the coupling of porous media flow; at the same time, it considered the effect of molecular slippage on seepage. It established mathematical model coupled gas migration and coal deformation phase by considering the drainage borehole in different in-situ stress, different initial permeability and drainage negative pressure condition. By studying borehole drainage of gas in the process, the change laws of permeability of coal seam and gas migration are achieved under the influence of different ground stress and gas pressure.