煤层水力压裂裂缝扩展演化特征及瓦斯渗流规律研究

Study on Fracture Propagation and Evolution Characteristics and Gas Seepage Law of Hydraulic Fracturing in Coal Seam

为了解决低渗透煤层瓦斯抽排难的问题,本文以杜家沟矿2104工作面为研究背景,利用数值模拟与现场实践相结合的方法对低渗透煤层水力压裂增透技术进行研究,发现随着水力压裂注液压力的增加,岩石裂缝扩展速度越快且扩展的长度越长,随着岩石弹性模量的增加,在注液压力一定时,岩石压裂裂缝的扩展长度越短。同时通过现场实践验证发现,经过水力压裂后低渗透煤层的瓦斯抽排效果明显较佳,验证了水力压裂对低渗透煤层增透技术的可行性,为矿井低渗透煤层瓦斯抽采提供参考与借鉴。

In order to solve the problem of gas drainage in low permeability coal seam,this paper takes 2104 working face of Dujiagou coal mine as the research background,and uses the method of combining numerical simulation with field practice to study the hydraulic fracturing permeability increasing technology in low permeability coal seam.It is found that with the increase of hydraulic fracturing injection pressure,the faster the rock fracture expansion speed is,and the longer the expansion length is.With the increase of elastic modulus of rock,when the injection pressure is constant,the propagation length of rock fracture is shorter.At the same time,through the field practice,it is found that the gas drainage effect of low permeability coal seam after hydraulic fracturing is obviously better,which verifies the feasibility of hydraulic fracturing on permeability increasing technology of low permeability coal seam,and provides reference for gas drainage of low permeability coal seam.