油套管特殊螺纹密封面接触应力松弛行为研究  

Study on contact stress relaxation on premium connections sealing surface of tubing and casing

作　　者：张颖 练章华[2] 周谧[1] 林铁军 Zhang Ying;Lian Zhanghua;Zhou Mi;Lin Tiejun(School of Mechanical Engineering,Sichuan University of Science&Engineering,643000,Zigong,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,610500,Chengdu,China)

机构地区：[1]四川轻化工大学机械工程学院,自贡643000 [2]西南石油大学油气藏地质及开发工程国家重点实验室,成都610500

出　　处：《应用力学学报》2019年第6期1355-1361,I0007,共8页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51574198);国家教育部博士点基金(20135121110005)

摘　　要：开展了P110T油套管材料的单轴拉伸高温蠕变试验,分析了P110T材料在不同温度、不同拉应力作用下的蠕变力学特性;运用约束最小二乘法建立了P110T材料蠕变速率的解析解数学模型,并根据材料松弛与蠕变的特征关系建立了P110T材料松弛力学规律的数学模型;采用实例分析的方法,得到了P110T油套管特殊螺纹密封面松弛应力的变化规律。结果表明,在相同初始接触应力条件下,温度越高,应力松弛变化现象越明显;在相同温度条件下,初始接触应力越高,密封失效所需的时间越长。Contact stress relaxation on the sealing surface of premium connection is considered as a main factor of the connection seals failure in the high temperature and high pressure gas well. In this paper, the creep tension tests of P110 T casing material are conducted in high temperature. The creep character of the materials is analyzed under the different temperature and tension stress conditions. Then, a mathematical model of P110 T creep strain rate is established by the Least Square method. According to the relationship between creep and relaxation presented, an innovation stress relaxation model is put forwarded from the creep strain rate. Finally, by applying the stress relaxation model, premium connection contact stress relaxation of sealing surface vary with time and temperature is obtained. Present study can be used for the design and evaluation of the premium connection structure. Meanwhile, it also can be applied to predict the premium connection service life in the high temperature gas well.

关 键 词：特殊螺纹 接触应力 密封机理 蠕变 应力松弛 

分 类 号：TE921.2[石油与天然气工程—石油机械设备]