考虑屈曲和摩擦力的高温高压井管柱力学分析  

Mechanical Analysis of Tubular in High Temperature and High Pressure Well Considering Buckling and Friction

作　　者：石小磊 黄文君[1] 高德利[1] Shi Xiaolei;Huang Wenjun;Gao Deli(MOE Key Laboratory for Petroleum Engineering,China University of Petroleum(Beijing))

机构地区：[1]中国石油大学(北京)石油工程教育部重点实验室

出　　处：《石油机械》2020年第11期111-118,共8页China Petroleum Machinery

基　　金：国家自然科学基金创新研究群体项目“复杂油气井钻井与完井基础研究”(51821092);国家科技重大专项“复杂结构井、丛式井设计与控制新技术”(2017ZX05009-003);国家自然科学基金青年项目“旋转钻柱动力屈曲临界条件与后屈曲蛇形摆动和螺旋涡动行为研究”(51904317);中国石油大学(北京)科研启动基金项目“长水平段钻柱动态摩阻扭矩计算模型与振动减阻技术研究”(ZX20180414)。

摘　　要：高温高压定向井测试管柱的力学行为复杂且管柱失效问题突出,涉及到温度、压力、井眼轨迹、管柱屈曲及摩擦力等一系列因素。常规的测试管柱力学模型适用于直井,对于定向井和水平井而言适用性差。当井斜存在时,除了考虑温度效应和鼓胀效应外,还应考虑管柱屈曲和摩擦力的作用。基于温度和压力模型计算了沿管柱的温度和压力分布。随后在平衡方程的基础上,考虑由于温度变化、压力变化、管柱屈曲和摩擦力而引起的管柱伸长或缩短以及管柱端部的约束条件,建立了测试管柱的力学模型,采用迭代法进行求解。最后以塔里木盆地的一口定向井为例对模型进行了应用。应用结果表明:摩擦力和螺旋屈曲可抑制轴向力在管柱上的传递,若忽略摩擦力和管柱屈曲的影响,管柱的有效轴向力则被高估;由于井口和封隔器的约束,随着生产时间的延长和产量的增加,管柱上的平均温度升高,管柱的螺旋屈曲段增大,轴向力减小;当地层温度和产量超过一定值时,管柱将进入屈服状态,或者封隔器无法封住管柱,给生产安全带来严重威胁;通过优化管柱元件以及在井口施加预紧力等措施,大大增加了测试管柱的安全操作范围。研究结果对高温高压定向井测试管柱的设计和优化具有重要意义。The mechanical behavior of the testing string in high temperature and high pressure directional well is complex and the failure problem is prominent,involving a series of factors such as temperature,pressure,well trajectory,string buckling and friction.The conventional testing string mechanics model is suitable for vertical wells,but has poor applicability for directional wells and horizontal wells.When the well deviation exists,in addition to the temperature effect and bulging effect,the buckling and friction of the tubular should also be considered.The temperature and pressure distribution along the tubular are calculated based on the temperature and pressure model.Based on the balance equation,considering the elongation or shortening of the tubular caused by temperature changes,pressure changes,string buckling and friction,and the constraints at the end of the tubular,a mechanical model of the testing string is established.Iterative method is used to solve the model.A directional well in the Tarim Basin is used as an example to apply the model.Application results show that friction and helical buckling can inhibit the transmission of axial force on the tubular.If the effect of friction and buckling of the tubular is ignored,the effective axial force of the tubular is overestimated.Due to the wellhead and packer constraint,as the production time increases and the output increases,the average temperature on the tubular increases,the spiral buckling section of the tubular increases,and the axial force decreases.When the formation temperature and oil output exceed a certain value,the tubular will enter a yielding state,or the packer will no longer seal the string,presenting a serious threat to production safety.Measures such as optimizing tubular components and applying pretightening force at the wellhead could greatly increase the safe operation range of the testing string.The research results are of great significance to the design and optimization of high temperature and high pressure directional well testing s

关 键 词：测试管柱 高温高压井 螺旋屈曲 摩擦力 轴向力 屈服状态 

分 类 号：TE921[石油与天然气工程—石油机械设备]