1.School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo , China; 2.Henan Provincial Collaborative Innovation Center of Coal Bed Methane (Shale Gas) in Central Plains Economic Zone, Jiaozuo , China

为研究煤储层水力冲孔孔洞形态和水力冲孔钻孔周围煤体渗透率演化规律，依据Bergmark-Roos方程，建立了水力冲孔孔洞形态特征方程并采用Matlab模拟再现了孔洞形态；以流固耦合和稳态蠕变理论为基础，采用数值模拟的方法查明了水力冲孔期间和水力冲孔后煤体渗透率的演化规律。研究结果表明：水力冲孔孔洞呈椭球体；水力冲孔期间，影响半径随出煤量的增加而增加，随时间的延长，影响半径内煤体渗透率增加并趋缓；水力冲孔后，煤体孔裂隙变形程度随时间延长而增大，渗透率减小；建立的流固耦合方程及数值模拟结果基本与现场吻合。

In order to study the permeability evolution law of coal surrounded of hydraulic flushed borehole shape and hydraulic flushed borehole in the coal reservoir, according to the Bergmark-Roos Equation, a shape feature equation of the hydraulic flushed borehole was established and the borehole shape was represented with the Matlab simulation. Based on the fluid-solid coupling and stable creep theory, the numerical simulation method was applied to prove through an investigation the permeability evolution law of the coal during the hydraulic flushing period and after the hydraulic flushing of the borehole. The study results showed that the hydraulic flushed borehole was in an ellipsoid. During the hydraulic flushing period, with the coal output increased, the influenced radius would increase.With the time passed, the coal permeability within the influenced radius would increase and then in stable. After the hydraulic flushing of the borehole, the cracking deformation degree of the coal borehole would increase with the time passed and the permeability would decrease.The results of the established fluid-solid coupling equation and the numerical simulation could be basically fitted to the site practices.