深层页岩气压裂井套管应力影响因素分析  

Analysis of Factors Influencing Casing Stress in Deep Shale Gas Fractured Wells

作　　者：林魂 宋西翔 孙新毅 杨兵 Lin Hun;Song Xixiang;Sun Xinyi;Yang Bing(College of Safety Engineering,Chongqing University of Science&Technology)

机构地区：[1]重庆科技学院安全工程学院,重庆市401331

出　　处：《石油机械》2022年第6期84-90,共7页China Petroleum Machinery

基　　金：国家科学自然基金项目“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“考虑化学渗透压的页岩储层压裂液渗吸机理与模型研究”(cstc2019jcyj-msxmX0457);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);重庆科技学院硕士研究生创新计划项目“深层页岩气压裂井水平段套管变形机制研究”(YKJCX2020721)。

摘　　要：为了研究深层页岩气压裂井套管应力的影响因素,采用数值模拟的方法,分析了温-压耦合作用、天然断层滑移和“密簇”压裂对套管应力的影响。研究结果表明:温-压耦合作用下,套管所受最大等效应力显著提高,且呈现出先快速下降后快速上升直至达到稳定的动态变化,套管应力随井筒内温差的增大而增加;套管在断层面处极易屈服变形,当断层滑移距离超过3 mm后,套管在断层面处开始受到明显的剪切应力,套管变形量随着滑移距离的增加而呈线性增长;簇间距离越小,套管内壁所受最大等效应力越大,“密簇”压裂还会增加套管所受应力的不均匀度,当射孔簇数从3簇增加到8簇时,应力离散度增幅达到29%。研究结果可为深层页岩气井水平段压裂过程中套管的损坏防治提供参考。In order to study the influencing factors of the casing stress in deep shale gas wells,numerical simulation was used to analyze the influences of temperature-pressure coupling,natural fault slip and multi-cluster fracturing on casing stress.The results show that the maximum equivalent casing stress is obviously increased under the coupling action of temperature and pressure,and it shows a dynamic change of rapidly decreasing first and then rapidly increasing until reaching stable.The casing stress increases with the increase of temperature difference in the wellbore.Casings are easy to yield and deform at the fault plane,when fault slip distance exceeds 3 mm,the casing is subject to obvious shear stress at the fault plane,and the casing deformation increases linearly with the increase of slip distance.Smaller distance between clusters results in greater maximum equivalent stress on the inner wall of casing.Furthermore,multi-cluster fracturing will increase the nonuniformity of casing stress.When the number of perforation clusters increases from 3 to 8 clusters,the stress dispersion increases by 29%.The study results provide a reference for the prevention and control of casing damage during horizontal fracturing in deep shale gas wells.

关 键 词：深层页岩气 温-压耦合 密簇压裂 套管应力 数值模拟 

分 类 号：TE934[石油与天然气工程—石油机械设备]