基于真三轴压裂试验的页岩损伤研究  

Study on shale damage based on true triaxial hydraulic fracturing test

作　　者：张健[1] 张国祥[1] 王金意[1] 马海春[2] ZHANG Jian;ZHANG Guoxiang;WANG Jinyi;MA Haichun(China Huaneng Group Clean Energy Technology Research Institute Co., Ltd., Beijing 102209, China;School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China)

机构地区：[1]中国华能集团清洁能源技术研究院有限公司,北京102209 [2]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《合肥工业大学学报（自然科学版）》2020年第10期1404-1409,共6页Journal of Hefei University of Technology：Natural Science

基　　金：中国华能集团资助项目(CERI/TY-16-HJKO3)。

摘　　要：为了解牛蹄组页岩的水力压裂破坏规律及特征,文章利用室内真三轴岩土工程模拟试验机及压裂泵压伺服控制系统、声发射定位系统,建立一套页岩水力压裂物理模拟试验系统。通过对无围压、有围压的试样分析,发现有围压下的试样泵压在峰值左右持续时间较长。通过对有围压的岩石设置水平地应力差异系数,发现地应力差异系数影响水力压裂前期初始裂缝的形成,水平地应力差异系数大更容易形成初始裂缝,中后期的裂缝扩展受天然裂隙影响较大。裂缝规律表现为:在泵压作用下试样内部发生剪切或拉伸破坏,沿射孔方向先发生起裂,后形成初始裂缝,压裂液渗流至初始裂缝内,当裂尖处的渗流水压力强度大于模拟岩样的断裂韧性值时,裂缝将向前延伸,再逐步演化成渗流通道。In order to understand the hydraulic fracturing law and characteristics of the Niutitang shale,this paper uses the indoor true triaxial geotechnical simulation test machine,the fracturing pump pressure servo control system and the acoustic emission positioning system to establish a set of shale hydraulic fracturing physical simulation test systems.By analyzing the specimen with or without confining pressure,it is found that the peak duration of the pump pressure under the confining pressure is longer than that without confining pressure.By setting the difference coefficient of horizontal ground stress of the confined rock,it is found that the difference coefficient of ground stress affects the formation of initial fracture in the early stage of hydraulic fracturing,the difference coefficient of horizontal ground stress is more likely to form the initial fracture,and the fracture propagation in the middle and late period is greatly affected by natural fissures.The fracture law is as follows:under the action of pump pressure,shear or tensile failure occurs in the specimen,and the initial fracture occurs after the perforation.After the initial fracture,the fracturing fluid flows into the initial fracture,when the water pressure intensity is greater than the fracture toughness value of the simulated rock specimen,the fracture will extend forward and gradually evolve into the seepage channel.

关 键 词：页岩 水力压裂 地应力差异系数 声发射 

分 类 号：P555[天文地球—构造地质学]