页岩层理弱面对裂缝穿层扩展的影响数值模拟研究  

Numerical simulation of the effect of weak shale bedding on fracture propagation through strata

作　　者：白岳松[1] 胡耀青[1] 何睿 廖兴川 谭劲 易良平 黄刘科 曹爱武 李杰 BAI Yuesong;HU Yaoqing;HE Rui;LIAO Xingchuan;TAN Jin;YI Liangping;HUANG Liuke;CAO Aiwu;LI Jiee(Institute of Mining Technology,Taiyuan University of Technology,Taiyuan 030024,China;Engineering Technology Research Institute,PetroChina Southwest Oil&Gas Field Company,Chengdu 610017,China;School of Civil Engineering and Geomatics,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Hydro-China Itasca R&D Center,Hangzhou 311122,China;China Coal Technology and Engineering Group Shenyang Research Institute,Fushun 113122,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]中国石油西南油气田公司工程技术研究院,四川成都610017 [3]西南石油大学土木工程与测绘学院,四川成都610500 [4]西南石油大学油气藏地质与开发国家重点实验室,四川成都610500 [5]浙江中科依泰斯卡岩石工程研发有限公司,浙江杭州311122 [6]中煤科工集团沈阳研究院有限公司,辽宁抚顺113122

出　　处：《煤矿安全》2023年第5期240-246,共7页Safety in Coal Mines

基　　金：国家自然科学基金资助项目(42002271);四川省自然科学基金资助项目(2022NSFSC1007);西南石油大学自然科学“启航计划”资助项目(2022QHZ009)。

摘　　要：层理弱面是影响页岩油气水力裂缝穿层扩展的关键因素之一,而层理弱面强度主要由黏结强度、内摩擦角以及抗张强度决定。为探究层理弱面对水力裂缝穿层扩展的影响机理,基于三维块体离散元法建立了含层理弱面页岩压裂数值模型,研究了黏结强度、抗张强度以及内摩擦角对水力裂缝穿层和裂缝扩展形态的影响。数值模拟结果表明:层理黏结强度对水力裂缝穿层扩展存在显著影响,黏结强度较低时水力裂缝主要为横向扩展,并伴随着较大的层理激活程度;而高黏结强度下水力裂缝穿层能力较强,主要呈近圆形扩展;层理激活主要为剪切破坏,即层理抗张强度对水力裂缝扩展无明显影响,在实际工程中可忽略不计;水力裂缝的穿层能力随内摩擦角的增大而增强,在低内摩擦角下水力裂缝易沿层理扩展。Bedding strength is one of the key factors affecting the propagation of hydraulic fractures through beddings,which is mainly determined by cohesion,internal friction angle and tensile strength.However,there are few researches on this.Therefore,in order to further study the influence mechanism of bedding strength on the propagation of hydraulic fractures through beddings.Based on the three-dimensional block discrete element method,this paper simulated the propagation morphology of hydraulic fractures under different cohesion,tensile strength and internal friction angle.The simulation results show that bedding cohesion has a significant influence on the propagation of hydraulic fractures through beddings.Under low cohesion,hydraulic fractures mainly shows transverse propagation,accompanied by a larger degree of bedding activation,however,at high bonding strength,the permeability of hydraulic fractures is strong,and the propagation is nearly circular.The tensile strength of bedding has no obvious effect on the propagation capacity of hydraulic fracture and can be ignored in practical engineering.The penetration of hydraulic fractures increases with the increase of internal friction angle,and the hydraulic fractures are easy to diffuse along bedding at low internal friction angle.

关 键 词：层理强度 水力压裂 三维离散元法 页岩 穿层扩展 

分 类 号：TD321[矿业工程—矿井建设]