穿层钻孔水力重复压裂增透技术研究及应用

Permeability Increasing Mechanism of Hydraulic Repeated Fracturing in Crossing-hole Drilling

基于张集矿煤层地应力高、透气性低的特点,为了改善张集矿井下瓦斯抽采效率,采用相似模拟与工程试验相结合的手段,研究得出了水力重复压裂煤层过程中裂隙发育、扩展演化特征以及上覆岩层卸压、增透机制。并提出了穿层钻孔'重复压裂'及'先压后冲'相结合的压裂技术增加煤层渗透性,并根据模拟结果合理选择现场压裂施工参数进行现场工程试验,结果表明,该水力压裂技术可以有效提高煤层瓦斯抽采量,缩短抽采达标时间。

In order to improve the efficiency of gas extraction in Zhangji Coal Mine,in view of the characteristics of high insitu stress and low permeability of the coal seam,similar tests and engineering applications are used to study the characteristics of fracture development,expansion and evolution in the process of coal seam hydraulic fracturing,and the mechanism of pressure relief and permeability enhancement in overburden strata.The fracturing technology combining'repeated fracturing'with'fracturing before flushing'through drilling holes is put forward to increase coal seam permeability.According to the simulation results,the field engineering test is carried out with reasonable fracturing parameters.The results show that the hydraulic fracturing technology can effectively improve the gas extraction quantity and shorten the time of meeting the standard.