浸泡条件下页岩力学及摩擦特征实验  

Experiments on mechanics and friction characteristics of shale under soaking conditions

作　　者：刘鹏林 李军[1,3] 连威 席岩 刘献博 王典 LIU Penglin;LI Jun;LIAN Wei;XI Yan;LIU Xianbo;WANG Dian(College of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China;Huabei Oilfield Company,PetroChina,Renqiu 062552,China;College of Petroleum,China University of Petroleum(Beijing)in Karamay,Karamay 834000,China;College of Architecture and Civil Engineering of Beijing University of Technology,Beijing 100124,China)

机构地区：[1]中国石油大学(北京)石油工程学院,北京102249 [2]中国石油华北油田公司,河北任丘062552 [3]中国石油大学(北京)克拉玛依校区石油学院,新疆克拉玛依834000 [4]北京工业大学建筑工程学院,北京100124

出　　处：《断块油气田》2024年第4期734-739,共6页Fault-Block Oil & Gas Field

基　　金：中国石油大学(北京)克拉玛依校区引进人才基金项目“页岩油气井全生命周期井筒完整性分析与优化体系构建”(XQZX20220019);国家自然科学基金青年科学基金项目“页岩气井多级压裂诱发断层滑移量化计算模型与套管变形控制方法研究”(5220040102);国家自然科学基金企业创新发展联合基金项目“海相深层高温高压钻完井工程基础理论及控制方法”(U19B6003-05)。

摘　　要：针对页岩水力压裂过程中的断层滑移问题,通过室内实验,分析了浸泡条件下页岩的力学及摩擦特征,研究了页岩摩擦因数演化规律。研究结果表明:1)页岩抗压强度、抗拉强度、弹性模量和黏聚力随浸泡时间的增加而降低;页岩泊松比随浸泡时间的增加而增加,内摩擦角变化规律不明显。2)页岩摩擦因数随浸泡时间、法向应力和取心夹角的增加而降低,浸泡6 h内页岩摩擦因数降幅较大,后趋于稳定。3)界面压力大于5 MPa后,页岩的摩擦因数不随界面压力的增加而变化,仅随浸泡时长的增加而降低。4)水力压裂结束后,摩擦因数持续降低,断层仍存在滑移风险,缩短压裂作业时长可避免摩擦系数持续降低对断层滑移的影响。研究结果可为页岩断层滑移预测提供科学依据。For the problem of fault slip during shale hydraulic fracturing,the mechanical and friction characteristics of shale under immersion conditions were analyzed by laboratory experiments,and the evolution laws of shale friction coefficient were studied.The results show that:(1)The compressive strength,tensile strength,modulus of elasticity and cohesion of shale decrease with the increase of soaking time;Poisson′s ratio of shale increases with the increase of soaking time,and the variation law of internal friction angle is not obvious.(2)The shale friction coefficient decreases with the increase of soaking time,normal stress and coring angle,and the shale friction coefficient decreases more within 6 h of soaking and then stabilizes.(3)After the interfacial pressure is greater than 5 MPa,the friction coefficient of shale does not change with the increase of interfacial pressure,but only decreases with the increase of soaking time.(4)After the end of hydraulic fracturing,the friction coefficient continues to decrease,and the fault still has the risk of slipping.Shortening the length of fracturing operation can avoid the influence of the continuous decrease of friction coefficient on the slip of the fault.The research results in this paper can provide a scientific basis for shale fault slip prediction.

关 键 词：岩石力学 页岩 强度 摩擦因数 浸泡时间 

分 类 号：TE257[石油与天然气工程—油气井工程]