煤层气抽采地面压裂与井下钻孔衔接时空关系研究

基于晋城矿区所采用“三区”联动抽采模式，结合生产区地面压裂作业与井下钻孔抽采在时间和空间上衔接相对紧密交叉影响大的特点，提出了生产区地面压裂与井下钻孔抽采两种时间衔接模式，即“压裂前后布置井下抽采钻孔”和“井下钻孔滞后地面压裂布置”。通过微地震法和井下钻孔揭露法研究，得出煤层中的裂缝主要为北东向开度较小的水平裂缝，裂缝长158~203 m。根据裂缝展布规律，设计了2种模式的压裂考察方案，通过工程实践，初步确定了地面压裂作业与井下抽采钻孔合理的时间衔接关系，在地面压裂前后布置钻孔抽采，对目标煤层的增透、减小煤层瓦斯异常涌出和煤与瓦斯突出危险性等方面效果明显，井下钻孔滞后地面压裂3个月以内施工，联合抽采效果显著。

Research on time and space connection of ground drilling fracturing and underground boreholes of gas drainage

According to the "three areas" linkage extraction mode in Jincheng mining area，according to the characteristics of the relationship of time and space which ground fracturing operation and underground extraction drill hole that are the more relatively closer and better interaction，two time connection modes were put forward about the ground fracturing operation and underground extraction，that is "downhole drilling construction before and after fracturing" and "downhole drilling construction lags behind the ground fracturing". Through the micro seismic method and downhole drilling expose research，it was obtained that，the cracks in coal seam are mainly of the north east and smaller opening horizontal crack，the length of cracks are about 158~203 m. From the laws of fracturing cracks，the two kinds of fracturing inspection scheme were designed，the reasonable relationship of time connection of the ground fracturing operation and underground extraction have been determined by the engineering practice，that is，the effect of drilling boreholes to drain gas is obvious before and after ground fracturing，the permeability was improved in target coal seam，abnormal gas emission and gas outburst dangers were also reduced，at the same time，the combined extraction effect is obvious when downhole of drilling lags behind the ground fracturing construction within 3 months.