不稳定流量水力压裂对深部低透气性煤层增透效果的影响  

The effect of unstable flow hydraulic fracturing on antireflection of deep low permeability coal seam

作　　者：何明川 HE Mingchuan(CCTEG Chongqing Research Institute,Chongqing 400037,China)

机构地区：[1]中煤科工集团重庆研究院有限公司,重庆400037

出　　处：《矿业安全与环保》2021年第3期90-93,99,共5页Mining Safety & Environmental Protection

基　　金：国家“十三五”科技重大专项项目(2016ZX0506004);国家自然科学基金项目(51874348)。

摘　　要：为了进一步提升深部低透气性煤层水力压裂增透效果,在煤层水力压裂相关理论研究及现场试验的基础上改进水力压裂工艺,根据相关的力学原理,推导得到压裂孔周边的应力随注水流量的变化情况,提出以控制注入水流量为原则,在水力压裂过程中采用不稳定注入水流量的方法,在平煤十二矿己15-31040工作面进行水力压裂试验。试验结果表明:通过注入不稳定水流量,克服了煤层深部高地应力对水力压裂施工的影响,且压裂过程顶板保持良好;经过测定与己15-31040工作面相邻的己15-31030工作面的常规稳定水流量压裂、未压裂区域瓦斯抽采数据,不稳定水流量压裂单孔抽采瓦斯浓度和瓦斯纯流量比常规水力压裂及未压裂区域均有明显提升。该方法对深部煤层水力压裂增透具有一定的指导作用。In order to further improve the antireflection effect of hydraulic fracturing of deep low permeability coal seams,based on the theories and field studies related to the hydraulic fracturing technology of coal seam,according to the relevant mechanical principles,the variation of the stress around the fracturing hole with the flow rate of water injection was deduced.Based on the principle of controlling the injection water flow,a method of unstable injection water flow in the process of hydraulic fracturing was proposed.The hydraulic fracturing test was carried out in the Ji 15-31040 working face of No.12 Coal Mine in Pingdingshan Coal Industry Group.The test results show that the influence of high in-situ stress in deep coal seam on hydraulic fracturing is overcome by injecting unstable water flow,and the roof is maintained in good condition during fracturing;after measuring the gas extraction data of conventional stable water flow fracturing and unfractured area of Ji 15-31030 working face adjacent to Ji 15-31040 working face,it is found that the concentration and pure flow of gas extracted from single hole in unstable water flow fracturing are significantly increased.This method has a certain guidance for the antireflection of deep coal seam hydraulic fracturing.

关 键 词：水力压裂 低透气性煤层 水流量 不稳定 增透 瓦斯抽采 

分 类 号：TD712.6[矿业工程—矿井通风与安全] TE357.11[石油与天然气工程—油气田开发工程]