复杂载荷作用下L80-1钢级石油套管应力分析  

Finite Element Analysis on Stress of L80-1 Grade Casing under Complex Load

作　　者：李承祥 于桂杰[1] 杨洪英 鲁高敏 Li Chengxiang;Yu Guijie;Yang Hongying;Lu Gaomin(College of Pipeline and Civil Engineering,China University of Petroleum(Huadong);Lufeng Oil Recovery Management Zone,Sinopec Lusheng Company)

机构地区：[1]中国石油大学(华东)储运与建筑工程学院 [2]中国石化鲁胜公司鲁丰采油管理区

出　　处：《石油机械》2021年第11期140-146,共7页China Petroleum Machinery

摘　　要：为了研究非均布地应力条件下石油套管的抗挤强度,以L80-1钢级套管为研究对象,建立了套管-水泥环-地层系统模型,对整个系统施加非均匀载荷以及剪切载荷,着重分析套管强度与地应力以及水泥环卸载之间的关系。分析结果表明:在非均布载荷下,随地应力非均布系数的增大,L80-1钢级套管抗挤强度大幅降低;地应力非均布系数为1.4时,水泥环卸载为61.1%;地应力非均布系数为1.7时,水泥环卸载为66.3%;随着地应力非均布系数的增大,居中度越大的套管抗挤强度越高,相同的套管居中度时地应力非均布系数越小,套管抗挤强度越高;水泥环厚度越大,其卸载作用越明显;水泥环对套管抵抗横向剪切力有显著效果。所得结论可为提高套管承载能力和制定预防套管损坏措施提供参考。In order to study the collapsing strength of oil casing under the condition of nonuniform distributed ground stress,taking the L80-1 grade casing as the research object,this paper built a casing-cement sheath-formation system model,then,applied nonuniform load and shear load on the whole system,and emphatically analyzed the relationship among casing strength,ground stress and cement sheath unload.The analysis results show that under the nonuniform distributed load,as the nonuniform distributed factor of ground stress increases,the collapsing strength of L80-1 grade casing largely reduces;when the nonuniform distributed factor of ground stress is 1.4,the cement sheath unload is 61.1%;when the nonuniform distributed factor of ground stress is 1.7,the cement sheath unload is 66.3%;as the nonuniform distributed factor of ground stress increases,the casing with greater centrality has higher collapsing strength;when the casing centrality is the same,the smaller the nonuniform distributed factor of ground stress,the higher the collapsing strength of casing is;the thicker the cement sheath,the more obvious the unloading effect is;and the cement sheath has remarkable effect on casing resisting lateral shear force.The conclusions provide reference for improving casing bearing capacity and formulating measures to prevent casing from damaging.

关 键 词：套管 抗挤强度 非均布地应力 水泥环 剪切载荷 居中度 

分 类 号：TE925[石油与天然气工程—石油机械设备]