不同滤失面下砂岩定向压裂声发射响应特征研究  

Study on acoustic emission response characteristics of sandstone directional fracturing under different filtration surfaces

作　　者：叶海陇 杨录胜 刘正和[1] 邓琼伟 YE Hailong;YANG Lusheng;LIU Zhenghe;DENG Qiongwei(Key Laboratory of In-situ Property-improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Institute of Energy,Yuci 030600,China)

机构地区：[1]太原理工大学原位改性采矿教育部重点实验室,山西太原030024 [2]山西能源学院,山西榆次030600

出　　处：《煤矿安全》2022年第4期62-67,共6页Safety in Coal Mines

基　　金：国家自然科学基金资助项目(51574174)。

摘　　要：为了研究不同滤失面下滤失对岩石定向水力压裂的影响规律,选用300 mm×300 mm×300 mm中间钻孔并且定向预制裂缝的砂岩试件,采用在试件表面涂抹防水剂的方法控制滤失,制作出滤失面依次减小的4组砂岩试件:未涂防水剂试件A、裂缝面涂防水剂试件B、孔壁涂防水剂试件C、全涂防水剂砂岩试件D,进行真三轴定向水力压裂并开展声发射实时监测,分析研究不同滤失面下砂岩试件声发射能量率、累积能量以及压裂后裂缝扩展延伸规律。结果表明:随着滤失面增大即滤失越大,砂岩试件声发射的能量率峰值呈现逐渐下降的趋势,而试件完成压裂破坏过程所需的累积能量逐渐升高;在压裂裂缝扩展延伸过程中,随着滤失面增大即滤失越大,压裂裂缝向最大主应力σ_(H)方向偏转越快,当压裂裂缝偏转到同一偏转角α时,压裂裂缝扩展延伸长度L会逐渐减小。In order to study the influence of filtration on rock directional hydraulic fracturing under different filtration surfaces,300 mm×300 mm×300 mm sandstone specimens with intermediate drilling holes and directional prefabricated fractures were selected,and the method of applying waterproofing agent on the specimen surface was used to control the fluid loss,and four groups of sandstone specimens with reduced filtration surface were made,including agent A without waterproofing,fracture surface coated with waterproofing agent B,hole wall coated with waterproofing agent C,fully coated with waterproofing agent sandstone specimen D.We carry out true triaxial directional hydraulic fracturing and real-time acoustic emission monitoring to analyze and study the acoustic emission energy rate,cumulative energy and fracture extension law of sandstone specimens under different filtration surfaces.The results show that with the increase of filtration surface,the peak value of acoustic emission energy rate of sandstone specimen decreases gradually,while the cumulative energy needed to complete the fracturing failure process of sandstone specimen increases gradually;in the process of fracture extension,with the increase of filtration surface,the greater the filtration loss,the faster the fracture deflects to the maximum principal stress σ_(H);when the fracture deflects to the same deflection angleα,the fracture extension length L will gradually decrease.

关 键 词：定向水力压裂 坚硬顶板 冲击灾害 滤失 声发射 能量率 累积能量 

分 类 号：TD324.2[矿业工程—矿井建设]