大位移井套管外壁磨损剩余强度变化规律研究  

Residual Strength Variation of Casing with Outer Wall Wear in Extended Reach Wells

作　　者：刘剑 李忠慧[1,2] 黄熠 胡棚杰 曹天宝 孟凡奇 Liu Jian;Li Zhonghui;Huang Yi;Hu Pengjie;Cao Tianbao;Meng Fanqi(Hubei Key Laboratory of Petroleum Drilling and Production Engineering;National Engineering Research Center of Oil&Gas Drilling and Completion Technology,School of Petroleum Engineering,Yangtze University;Zhanjiang Branch of CNOOC(China)Co.,Ltd.)

机构地区：[1]油气钻采工程湖北省重点实验室,湖北省武汉市430100 [2]长江大学石油工程学院油气钻完井技术国家工程研究中心 [3]中海石油(中国)有限公司湛江分公司

出　　处：《石油机械》2025年第4期132-138,共7页China Petroleum Machinery

基　　金：中海石油(中国)有限公司项目“南海西部油田上产2000万m3钻完井关键技术研究”(CNOOC-KJ135ZDXM38ZJ05ZJ)。

摘　　要：目前针对套管磨损的研究集中在内壁磨损,但在大位移井下套管过程中,套管外壁磨损不可忽略,研究套管外壁磨损后剩余强度变化规律对套管柱强度校核具有重要意义。依据弹塑性力学理论,采用数值模拟方法建立了套管外壁磨损有限元分析模型;结合第四强度理论,研究了不同外壁磨损深度、套管钢级、外壁磨损半径和套管轴向载荷对套管强度的影响。研究结果表明:在外挤载荷作用下,套管外壁磨损后von Mises应力最大值出现在磨损最深处的外壁上,且受应力集中效应影响,随着磨损深度增加,套管磨损区内、外壁应力不均匀分布明显加剧;随着磨损深度的增加,套管剩余强度逐渐下降,当磨损深度大于2.19 mm时,N80钢级生产套管均有损坏风险;在相同磨损深度下,磨损半径越大,套管剩余强度越小;轴向压应力可以增大套管剩余强度,轴向拉应力会减小套管剩余强度。所得结果可为套管磨损后的损坏提出预警,为套管柱全寿命周期强度校核提供参考。Existing researches on casing wear mostly focus on inner wall wear of casing,but the outer wall wear of casing when it is lowered in extended reach wells cannot be ignored.Studying the residual strength variation of casing with outer wall wear is of great significance for the strength check of the casing string.In this paper,based on the theory of elastic-plastic mechanics,a finite element model of casing with outer wall wear was built using the numerical simulation method.Then,combined with the fourth strength theory,the influences of outer wall wear depth,casing grade,outer wall wear radius and axial load on casing strength were investigated.The results show that under the action of collapse loading,the maximum von Mises stress of casing with outer wall wear occurs on the outer wall at the largest wear depth.Due to the stress concentration effect,as the wear depth increases,the uneven distribution of stress on the inner and outer walls of the casing wear zone is significantly intensified.As the wear depth increases,the residual strength of the casing gradually decreases.When the wear depth exceeds 2.19 mm,all N80 grade production casings are prone to damage.At the same wear depth,the larger the wear radius,the smaller the residual strength of the casing.The axial compressive stress can increase the residual strength of the casing,while the axial tensile stress can decrease the residual strength of the casing.The study results help predict any casing damage after wear,and provide a reference for the strength check of the casing string in its life cycle.

关 键 词：套管磨损 剩余强度 轴向载荷 大位移井 磨损半径 von Mises应力 

分 类 号：TE925[石油与天然气工程—石油机械设备]