Research on Gas Migration Output Features Based on Coal Body Structure

We established flow pattern discrimination method based on GSI by analyzing gas flow pattern discrimination method and analyzed coal gas migration laws of GSI ≥ 45 and GSI <45, the results show that when GSI ≥ 65, bedding / cleats of coal body structure become the controlling factors of gas migration. Two migration modes including diffusion-seepage or seepage occur when starting pressure gradient is over the gas pressure gradient. When GSI = 45 to 65, gas migration laws are similar with the traditional fragmentation coal, it can achieve high-speed linear or non-linear seepage flow (turbulent), internal gas of matrix blocks transport relying on the diffusion. While migration mode for GSI <45 is two poles diffusion.