复合增透技术在高瓦斯低渗透煤层中的应用  

Application of Composite Anti-reflection Technology in High Gas and Low Permeability Coal Seam

作　　者：葛毓 GE Yu(Shaanxi 131 Coal Geology Co.,Ltd.,Hancheng 715400,China)

机构地区：[1]陕西省一三一煤田地质有限公司,陕西韩城715400

出　　处：《煤炭技术》2021年第9期94-98,共5页Coal Technology

基　　金：陕西省自然科学基础研究计划项目(2020JQ-1000)。

摘　　要：针对高瓦斯低渗透煤层透气性差、渗透率低导致瓦斯抽采效率低,制约矿井安全高效开采等问题,提出水力压裂与CO2相变气爆致裂复合作用增加煤层透气性的技术方案。采用RFPA2D-Flow软件对不同水压作用下钻孔周边煤体裂纹形成过程及向四周延展的规律进行模拟分析,采用FLAC3D软件对在不同长度预裂缝条件下CO2相变气爆致裂作用的影响程度进行模拟分析,同时在常村煤矿3106工作面进行工业试验。模拟分析和现场验证结果表明:水力压裂试验中,水压达到28 MPa时,作用的有效影响半径达到2.5 m;CO2相变气爆致裂作用影响区域范围与预裂缝长度之间呈线性关系,采用复合增透法能够使煤体的有效影响作用半径由2.5 m提高到7 m,通过30 d的现场数据采集分析,瓦斯压力由原0.43 MPa降低到0.15 MPa,瓦斯抽采效果显著,为类似条件下煤层瓦斯抽采提供技术参考。Aiming poor permeability of high gas and low permeability coal seam, low gas drainage efficiency caused by low permeability, restricting the safe and efficient mining of coal mine, puts forward the technical scheme of hydraulic fracturing combined with CO2 phase change gas explosion to increase the permeability of coal seam. RFPA2D-Flow software was used to simulate and analyze the formation process of coal cracks around the borehole under different water pressures and the law of extension to the surrounding;FLAC3D software was used to simulate and analyze the effect of CO2 phase change gas explosion on pre fracture with different length, and industrial test was carried out in 3106 working face of changcun coal mine. The results of simulation analysis and field verification show that the effective radius of hydraulic fracturing is 2.5 m when the hydraulic pressure reaches 28 MPa;there was linear relationship between the influence area of CO2 phase change gas explosion and the length of pre fracture. The effective influence radius of coal body can be increased from 2.5 m to 7 m by using the combined permeability increasing method. Through 30 days of field data collection and analysis, the gas pressure was reduced from 0.43 MPa to 0.15 MPa, and the gas drainage effect was very significant,which provides technical reference for coal seam gas drainage under similar conditions.

关 键 词：高瓦斯煤层 低渗透 水力压裂 气爆致裂 数值模拟 

分 类 号：TD712.6[矿业工程—矿井通风与安全]