定向射孔多孔同步压裂裂缝交互扩展规律研究  

Study on the Interactive Propagation Law of Fracture in Direetional Perforation Porous Synchronous Fracturing Technology

作　　者：丁一 张东峰[1] 张小强[1] 姜玉龙[1] 王开[1] DING Yi;ZHANG Dongfeng;ZHANG Xiaoqiang;JIANG Yulong;WANG Kai(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024

出　　处：《矿业研究与开发》2023年第9期91-98,共8页Mining Research and Development

基　　金：国家自然科学基金项目(52104097,51904197,51974194);山西省基础研究计划项目(20210302124352,20210302123147)。

摘　　要：针对传统切顶卸压沿空留巷技术很难控制顶板变形垮落等问题,为了更好地掌握切顶卸压时顶板的裂缝扩展规律,提出定向射孔多孔同步压裂切顶卸压方案并进行试验研究。在传统压裂试验过程中,射孔间距、注液速率对裂缝扩展效果影响较大,通过结合真三轴压裂渗流模拟试验系统与声发射监测系统,对300mm的立方体砂岩试件进行模拟试验。结果表明:声发射监测的声发射(AE)事件分布图能很好地反映出试件压裂过程中每个阶段的裂缝扩展形态和裂缝扩展规律;裂缝长度、起裂压力和裂缝缝网面积随横向射孔间距的增大而增大,裂缝宽度随射孔间距的增大而减小;随着注液速率的增大,主裂缝产生的次生裂缝减小,裂缝偏移现象也减少,复杂的裂缝也变得单一;压裂初期,裂缝从各射孔端部起裂,随着压裂的进行,射孔端部的裂缝变得复杂,主裂缝会沿着射孔方向扩展,形成横向射孔之间的贯通缝,最终裂缝从试件表面中部起裂扩展延伸至两端。研究结果可为定向射孔切顶卸压设计与施工提供一定的参考依据。For the traditional top-cutting and pressure-relieving goal-side roadway retention technology,it is difficult to control roof deformation and collapse.In order to better master the fracture propagation law of roof during top-cutting and pressurerelieving,a scheme of top-cutting and pressure-relieving by directional perforation porous synchronous fracturing was proposed and tested.In the process of traditional fracturing test,perforation spacing and liquid injection velocity have great impacts on the effect of fracture propagation.By combining the true triaxial fracturing seepage simulation test system with the acoustic emission monitoring system,a group of 300 mm cube sandstone specimens were used for simulation test.The results show that the acoustic emission(AE)event distribution map of acoustic emission monitoring can well reflect the fracture propagation morphology and fracture propagation law of each stage in the fracturing process of the specimen.The fracture length,initiation pressure and fracture mesh area increase with the increase of transverse perforation spacing,while the fracture width decreases with the increase of perforation spacing.With the increase of liquid injection velocity,the secondary fractures produced by the main fracture reduce,the phenomenon of fracture migration also reduces,and the complex fractures become single.In the initial stage of fracturing,the fracture starts from each perforated end.With the progress of fracturing,the fracture at the perforated end becomes complicated.The main fracture will expand along the perforated direction to form connected fracture between transverse perforations.Finally,the fracture starts from the middle of the specimen surface to extend to both ends.The research results can provide some reference for the design and construction of directional perforation top-cutting and pressure-relieving.

关 键 词：定向射孔 射孔间距 注液速率 声发射监测 射孔贯通缝 

分 类 号：TD322[矿业工程—矿井建设]