关键词: 瓦斯抽采, 双孔双渗透率, 流固耦合模型, 有效抽采半径

Abstract: In order to eliminate the influence of matrix gas seepage effect on the flow-solid coupling model and accurately describe the gas transport law in the extraction process, a two-hole dual permeability model that is more consistent with the characteristics of coal seam porous media is established, and a two-hole dual permeability flow-solid coupling model that considers the Klinkenberg effect and dy-namic gas diffusion coefficient is proposed. COMSOL was used to simulate the gas extraction process of the borehole and analyze the changes of gas transport pattern, permeability and effective extraction radius during the pre-pumping process of the coal seam borehole. The simulation results show that the Klinkenberg effect effectively promotes gas transport, and the permeability is the result of skeletal compression and matrix contraction, with the increase of extraction time, the matrix contraction dominates and the permeability gradually increases. The seepage velocity at the observation point can be divided into three stages: rapid rise, slow decline and stable and constant. The effective extraction radius of gas is in accordance with the power index function of extraction time and hole diameter. The field test basically matches with the simulation results, which verifies the correctness of the theoretical coupling model and provides a theoretical basis for gas extraction design.