水力冲孔煤层瓦斯分区排放的形成机理研究

Study on formation mechanism of gas emission partition in hydraulic flushing coal seam

为了探究水力冲孔之后煤层中瓦斯的分布规律,基于潘三矿13-1煤层的赋存条件,介绍了水力冲孔后瓦斯压力考察的现场试验。并结合RFPA2D-Flow软件模拟水力冲孔后煤层裂隙发育的过程,研究了水力冲孔对煤层地应力和瓦斯压力分布的影响。结果表明:水力冲孔卸压增透就是在冲孔孔洞周围煤体重新构建不稳定平衡状态的过程;水力冲孔之后会在孔洞周围由近及远依次形成瓦斯充分排放区、瓦斯排放区、瓦斯压力过渡区和原始瓦斯压力区;在冲孔的卸压增透区域会经历应力升高、裂隙发育、应力快速释放和恢复平衡的过程。

In order to search for the gas distribution in the coal seam after hydraulic flushing,introduced a hydraulic flushing field test on the investigation of gas pressure based on Pansan No.13-1 coal seam occurrence condition.By using RFPA2D-Flow software to simulate the process of coal fracture with hydraulic flushing,studied the effects of hydraulic flushing in seam stress and gas pressure distribution.The results indicat that hydraulic flushing pressure-relief and permeability is a process of the coal around punching holes and rebuild its unstable equilibrium.Around the holes from near and far would form four regions：gas full emission region,gas emission region,gas pressure transition region and natural gas region.The coal in the pressure-relief and permeability region could experience the processes of stress increase,fracture development,stress quick release and recovery equilibrium.