温-压耦合作用下断层滑移对套管应力的影响  

Influences of Fault Slip on Casing Stress Under Temperature-Pressure Coupling Effect

作　　者：林魂 宋西翔 杨兵 袁勇 张健强 孙新毅 Lin Hun;Song Xixiang;Yang Bing;Yuan Yong;Zhang Jianqiang;Sun Xinyi(School of Safety Engineering,Chongqing University of Science&Technology;Chongqing Institute of Geology and Mineral Resources)

机构地区：[1]重庆科技学院安全工程学院 [2]重庆地质矿产研究院

出　　处：《石油机械》2023年第6期136-142,158,共8页China Petroleum Machinery

基　　金：国家自然科学基金项目“基于低场核磁共振技术的页岩气储层‘焖井’增产机理研究”(51904050);重庆市自然科学基金面上项目“页岩气井壁稳定与微纳米孔缝封堵机理研究”(cstc2019jcyj-msxmX0798);油气生产安全与风险控制重庆市重点实验室开放基金项目“深层页岩气储层压裂作业下水平段套管损坏机理研究”(cqsrc202108)。

摘　　要：页岩气水平井段在压裂过程中容易诱发天然断层滑移,进而导致套管产生失效变形,影响页岩气生产。为研究断层滑移对水平段套管应力的影响机制,采用数值模拟的方法,借助ANSYS软件,建立了断层滑移有限元模型,研究在温-压耦合作用下的断层夹角、注液温差和水泥环弹性模量对套管应力的影响。研究结果表明:考虑温-压耦合作用会提高断层滑移对套管应力的影响;断层夹角越大,套管应力的增长幅度越小,且断层夹角越大,温-压耦合效应越明显;注液温差提高了断层滑移对套管应力的影响,当注液温差超过100℃时,套管应力会出现较大增幅;套管应力随水泥环弹性模量的增加呈现出先减小后增大的趋势,当滑移距离超过4 mm后,水泥环对套管的保护作用将大幅下降。研究结果可为预防页岩气井水平段套管失效变形提供一定参考。Natural fault slip is easily induced in the horizontal well of shale gas during fracturing process and causes casing failure and deformation,which affects the production of shale gas.In order to study the influence mechanism of fault slip on casing stress in horizontal section,the numerical simulation method was adopted.The finite element model of fault slip was established by ANSYS to study the effects of fault angle,liquid injection temperature difference and cement elastic modulus on casing stress under temperature pressure coupling.The results show that,the temperature pressure coupling can significantly improve the influence of fault slip on casing stress.The greater the fault angle,the smaller the increase of casing stress.And greater the fault angle results in more obvious temperature pressure coupling effect.The increase of liquid injection temperature difference can increase the influence of fault slip on casing stress,the casing stress will increase obviously when the temperature difference of liquid injection exceeds 100℃.The casing stress decreases first and then increases with the increase of elastic modulus of cement,when the fault slip distance exceeds 4 mm,the protective effect of cement on casing will be greatly reduced.The findings of this research provide references for preventing casing deformation and failure of shale gas horizontal wells.

关 键 词：页岩气水平井 压裂 温-压耦合 断层滑移 套管应力 断层夹角 有限元 

分 类 号：TE934[石油与天然气工程—石油机械设备]