煤矿地面水力压裂增透技术研究及应用

为了提高煤层的透气性、强化井下瓦斯抽采，采用地面大排量压裂、井下抽采的井上下联合工艺。通过分析地层应力的分布特点和水压破裂规律，给出水压裂缝的两种典型形态，计算裂纹在平面应力状态下的位移场，得到了基于水力压裂变缝高椭圆压裂形态的压裂半径理论计算公式，为地面压裂设计提供依据。提出了煤矿地面压裂井下抽采的压裂工艺系统，给出了压裂位置的布置原则。在寺河矿进行地面压裂试验，压裂增透后瓦斯抽采量较原始孔提高了3.65倍，压裂孔抽采瓦斯累计量为218.66万m³，压裂半径120 m，达到了较好的压裂增透效果。

Study and Application of Surface Hydraulic Fracturing Technology for Permeability Improvement in Coal Mine

In order to improve the permeability of coal seams and enhance the underground gas drainage，the combined gas drainage technology of surface powerful hydraulic fracturing and underground gas drainage was adopted．Through the analysis on the distribution characteristics of the strata stress and the fracturing law of the coal seam under water pressure，two typical shapes of hydraulic fractures were given，the displacement field of the fractures under the conditions of the plane stress was calculated，and the theoretical calculation formula of the fracture radius based on the highly elliptical fracturing shape of the fracture was obtained，this provided the basis for the surface fracturing design．Also，the fracturing technology system for surface fracturing and underground drainage was proposed and the location principle of fracturing was put forward．The surface fracturing tests were carried out in Sihe Coal Mine，the test results showed that the drainage quantity was 3．65 times higher than the original hole after permeability improvement by fracturing，the accumulated gas drainage quantity by fracturing holes was 2 186 600 m³，the fracture radius was 120 m，and the better permeability improvement effect by fracturing was achieved．