水力压裂增透技术在南桐煤矿的应用研究

Hydraulic fracturing technology and its applications in Nantong Coal Mine

为探索低渗煤层的瓦斯抽采增产关键技术,提高瓦斯抽采效率,缩短抽采达标时间,针对南桐煤矿瓦斯治理中的难题,开展了煤矿井下水力压裂增透抽采瓦斯技术研究。研究结果表明:水力压裂可在煤层中形成一组沿最大主应力方向延伸、最小主应力方向张开的径向张性裂缝,明显提高煤层的透气性;南桐煤矿K2煤层最大破裂压力为32.0MPa,选择压力为38.0MPa的设备工况进行压裂,单孔平均压入水量400m3左右;-325m7511工作面压裂后钻孔平均每米抽采贡献量是传统工艺的49倍,减少了预抽钻孔工程量,降低了成本,提高了瓦斯抽采效果。

In order to explore the key technology of increasing production by gas drainage in low permeability coal seam,improve the gas drainage efficiency and shorten the time of reaching the standard,according to the problems in gas control in Nantong Coal Mine,the research on gas drainage technology with hydraulic fracturing and permeability enhancement was carried out.The results show that hydraulic fracturing can form a group of radial tensile fractures extending along the direction of maximum principal stress and opening in the direction of minimum principal stress,which can significantly improve the permeability of coal seam;the maximum fracture pressure of K2 coal seam in Nantong Coal Mine is 32.0mpa,and the equipment condition with pressure of 38.0mpa is selected for fracturing,and the average water inflow per hole is about 400m3;After fracturing in-325m7511 working face,the average drainage contribution per meter of borehole is 49 times of that of traditional technology,which reduces the engineering amount of pre drainage drilling,reduces the cost and improves the gas drainage effect.