顺层长钻孔多缝槽控制压裂裂缝扩展规律研究  

Research on law of hydraulic fracturing crack propagation controlled by multi-preset slots in long drilling of coal seam

作　　者：薛伟超 李艳增 齐黎明[4] 仇海生 季淮君[5] XUE Weichao;LI Yanzeng;QI Liming;QIU Haisheng;JI Huaijun(China Coal Technology and Engineering Group Shenyang Research Institute,Fushun 113122,China;State Key Laboratory of Coal Mine Safety Technology,Fushun 113122,China;School of Mines,China University of Mining and Technology,Xuzhou 221116,China;School of Safety Engineering,North China Institute of Science and Technology,Beijing 101601,China;School of Engineering and Technology,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中煤科工集团沈阳研究院有限公司,辽宁抚顺113122 [2]煤矿安全技术国家重点实验室,辽宁抚顺113122 [3]中国矿业大学矿业工程学院,江苏徐州221116 [4]华北科技学院安全工程学院,北京101601 [5]中国地质大学(北京)工程技术学院,北京100083

出　　处：《煤矿安全》2021年第4期182-188,共7页Safety in Coal Mines

基　　金：“十三五”国家科技重大专项资助项目(2016ZX05045-004-001);煤科集团沈阳研究院有限公司科技创新基金资助项目(SYYD-20WS-002,SY-19-004)。

摘　　要：预置缝槽控制是解决煤岩体水力压裂空白带的有效措施。以唐口煤矿为例,采用RFPA软件,分析煤矿井下工作面顺层长钻孔预置多缝槽控制压裂裂缝扩展规律。研究表明:多缝槽控制压裂水压主裂缝全部沿垂直于最小水平主应力的方向扩展,存在优势缝槽优先诱导产生水压裂缝扩展;随着预置缝槽密度增大,单侧水压主裂缝的长度减小而裂缝张开角增大,单侧最大水压主裂缝的长度变化大致符合线性关系;平均单侧最大水压主裂缝长度为26.3 m,平均裂缝张开角为11.8°,裂缝稳定扩展压力为18.0 MPa;合理的缝槽密度为0.04 m^(-1),对应的缝槽间距为25 m;单孔平均卸压2537 m^(2),水压主裂缝区域渗透率可以提高100~200倍。Preset slot is an effective control measure to solve the blank zone problem appeared in the coal and rock mass hydraulic fracturing.Taking Tangkou Coal Mine as an example,RFPA software was used to analyze the crack propagation law controlled by the preset slots on the long drilling along the coal seam strata of the working face.The research shows that:all the main hydraulic fractures controlled by the multi-slot fracturing expand in the direction perpendicular to the minimum horizontal principal stress.There are some preset slots that can preferentially induce hydraulic crack propagation.As the density of the preslots increases,the length of the unilateral main hydraulic crack decreases and the crack opening angle increases.The length change of the longest unilateral main hydraulic crack roughly conforms to the linear relationship.The average length of the longest unilateral main hydraulic crack is 26.3 m.The average crack opening angle is 11.8°.The stable pressure of the crack propagation is 18.0 MPa.The reasonable slot density is 0.04 m,and the corresponding slot spacing is 25 m.The average pressure relief area of a single hole is 2537 m^(2).The permeability of the main fracture area can be increased by 100 to 200 times.

关 键 词：预置缝槽 缝槽间距 水力压裂 裂缝扩展 张开角 裂缝长度 扩展压力 

分 类 号：TD712[矿业工程—矿井通风与安全]