高温井井口抬升工况套管螺纹热应力行为  

Thermal Analysis and Failure Risk Assessment of Casing Thread under Wellhead Uplifting in High Temperature Wells

作　　者：罗涛 尹飞 苏鹏[2] 黄干 叶鹏举 LUO Tao;YIN Fei;SU Peng;HUANG Gan;YE Pengju(College of Energy,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Engineering and Technology Research Institute,Sinopec Northwest Oilfield Company,Urumqi,Xinjiang 830011,China)

机构地区：[1]成都理工大学能源学院,四川成都610059 [2]中国石化西北油田分公司石油工程技术研究院,新疆乌鲁木齐830011

出　　处：《石油管材与仪器》2024年第3期46-50,I0004,共6页Petroleum Tubular Goods & Instruments

基　　金：国家自然科学基金青年科学基金项目“基于地质力学与机器学习的压裂诱发裂缝滑移及套管变形预测方法”(编号:51904038);四川省科技计划项目“废弃深井改造地热井纳米流体旋流强化传热机制研究”(编号:2022NSFSC0249)。

摘　　要：高温高压井生产过程中出现井口抬升现象,增加了套管螺纹失效的风险,评价井口抬升工况下套管螺纹失效风险是井筒完整性的基础。采用有限元法和实验法,建立了套管螺纹的热应力模型,分析了不同温度与轴向力作用下套管螺纹的力学行为。研究表明:高温高压井套管螺纹失效风险较高,螺纹啮合处两端的螺纹牙容易出现应力集中;井口温度为33℃时,随着拉力增加,套管螺纹的最大应力值增加,当拉力达到3350 kN时,偏梯形套管螺纹最大应力为758 MPa,有屈服失效的风险;随着温度的增加,井口抬升量呈线性增大的趋势,而套管螺纹最大应力值也会随之增加。建议在高温井生产时,应选择合适产量或使用隔热管降低螺纹的工作环境温度,以保证现场安全生产。研究成果为高温高压井筒完整性评价提供技术支撑。The wellhead uplifting phenomenon occurs during the production of high temperature and high-pressure wells,which increases the risk of casing thread failure.Evaluating the risk of casing thread failure under wellhead uplifting conditions is fundamental to well integrity.Using the finite element method and experimental method,a thermomechanical model of casing threads is established to analyze the mechanical behavior of casing threads under the action of different temperatures and axial forces.The study shows that the risk of casing thread failure in high-temperature and high-pressure wells is high,and the thread teeth at both ends of the thread engagement are prone to stress concentration.The maximum stress value of the casing thread increases as the tension rises,and when the tension reaches 3350 kN(the wellhead temperature is 33℃),the maximum stress of the casing thread reaches 758 MPa,which means there is a risk of yielding failure.As the temperature increases,the wellhead uplifting tends to increase linearly,and the maximum stress value of the casing thread also increases.It is recommended that when high temperature wells are producing,suitable production output should be selected or heat insulation tubes should be used to reduce the working environment temperature of the threads to ensure safe production on site.The research results provide technical support for HTHP well integrity evaluation.

关 键 词：高温高压 井口抬升 套管螺纹 密封性 

分 类 号：TE21[石油与天然气工程—油气井工程]