顺煤层水力割缝抽采煤层瓦斯渗流规律数值模拟

为得到顺煤层水力割缝抽采瓦斯渗流规律以及预测水力割缝后瓦斯气体抽采量，结合渗流力学和弹塑性力学理论，建立了水力割缝抽采煤层瓦斯的固流耦合数学模型，同时给出了相应初始条件及边界条件。利用Madab计算得到顺煤层水力割缝后煤体应力场、瓦斯压力场以及瓦斯抽采量变化规律。数值模拟结果显示：水力割缝后，煤体有效体积应力得到释放；沿割缝方向储层卸压效果明显；煤层内裂隙、裂缝数量增加，长度和张开度增大；煤体渗透性能增强；煤层气抽采量较普通钻孔有较大幅度的提高。模拟结果显示了顺煤层水力割缝抽采煤层气的优势。此模拟方法对煤层气增产工业中确定水力割缝工艺参数以及预测瓦斯产量具有重要的指导意义。

Numerical Simulation of Coal-bed Methane Seepage Rule with Hydraulic-cutting Seam along Coal Seam for Mine

To gain the seepage rule and productivity prediction of hydraulic-cutting seam along coal seam for CBM mine ,the theory of seepage mechanics combined with elastic-plastic mechanics is used to set up a fluid-solid coupling mathematical model. Meanwhile, the boundary conditions and initial conditions are given. MATLAB is used to get the variation rule of coal-bed stress field, gas pressure field and gas mine yield. The simulation results show that after hydraulic-cutting seam is adopted, the effective stress is released; the effect of unload is obvious along seam; the numbers of crack and fracture increased;the length and width of crack and fracture is improved. So the permeability of coal seam enhanced. The mine yield of gas is bigger than common drilling to hydraulic-cutting seam. The advantage of hydraulic-cutting seam along coal seam for CBM mine is indicated. The method of simulation is significant to the execution project and productivity prediction of hydraulic -cutting seam for CBM industrial production increase technology.