特殊螺纹接头选用技术研究

发布时间：2018-06-13 00:28

本文选题：特殊螺纹接头 + 油管　；参考：《西安石油大学》2012年硕士论文

【摘要】：特殊螺纹接头靠密封面的过盈配合实现密封,扭矩台肩起过扭保护作用并兼顾辅助密封,而螺纹部分仅起连接作用,因此特殊螺纹接头具有良好密封性能。为保证特殊螺纹接头良好的密封性能,应根据井下工况合理选用特殊螺纹接头,若特殊螺纹接头类型选用不当,将会影响接头的完整性,引发管柱泄漏甚至失效。因此,本文分析了特殊螺纹接头的结构特点及影响接头完整性的因素。用有限元法分析了在上扣扭矩、轴向力、内压及轴向力与内压共同作用下某特殊螺纹油管接头的接触压力及等效应力分布规律。结合相关标准及文献,给出特殊螺纹接头选用推荐作法,为特殊螺纹接头的选用提供参考依据。本文分析了特殊螺纹接头的结构特点及井下工况(上扣扭矩、轴向力、内压、弯矩、温度及酸性气体)对其完整性的影响。以某特殊螺纹油管接头为研究对象,用非线性有限元分析方法,建立了油管接头有限元模型,分析了上扣扭矩、轴向力、内压及轴向力与内压共同作用下特殊螺纹油管接头密封面、扭矩台肩和螺纹处的接触压力和等效应力分布规律。为了便于对比特殊螺纹接头的特性,用有限元法对同尺寸的API油管接头进行对比分析。结果表明：以最佳扭矩上扣时,特殊螺纹接头的密封面、扭矩台肩和螺纹部分应力分布较合理；若轴向拉力大于400kN,接头两端的螺纹产生应力集中现象,此处易发生粘扣；当内压达到80MPa时,密封面等效应力超过材料的屈服强度,因此处为压应力,接头能够保持密封效果,若内压继续增大,管体部分首先屈服。在上扣及内压载荷作用下,API油管接头接触压力和等效应力分布规律均为两端高、中间低；若内压大于40MPa,API接头两端螺纹的应力集中现象较明显,此处容易发生粘扣或屈服破坏。本文基于特殊螺纹接头的结构分析及有限元分析,并结合相关标准及文献,给出了特殊螺纹接头选用推荐作法,并给出常用特殊螺纹接头性能评价表,为特殊螺纹油管接头的选用提供参考。
[Abstract]:The special thread joint is sealed by the interference fit of the sealing surface, the torque table shoulder plays an overtorsion protection function and takes into account the auxiliary seal, while the thread part only acts as a connection, so the special thread joint has good sealing performance. In order to ensure the good sealing performance of the special thread joint, the special thread joint should be reasonably selected according to the downhole working conditions. If the type of the special thread joint is not selected properly, the integrity of the joint will be affected and the string leakage or even invalidation will be caused. Therefore, the structural characteristics of special threaded joints and the factors affecting the integrity of joints are analyzed in this paper. The contact pressure and equivalent stress distribution of a special threaded tubing joint under the combined action of upper buckling torque axial force internal pressure and internal pressure are analyzed by finite element method. Combining with the related standards and literatures, the recommended method of selecting special thread joint is given, which provides the reference for the selection of special thread joint. In this paper, the structural characteristics of special threaded joints and the effects of downhole working conditions (buckling torque, axial force, internal pressure, bending moment, temperature and acid gas) on their integrity are analyzed. Taking a special threaded tubing joint as the research object, the finite element model of the tubing joint is established by using the nonlinear finite element analysis method, and the upper buckling torque and axial force are analyzed. Under the combined action of internal pressure and axial force and internal pressure, the distribution law of contact pressure and equivalent stress of special threaded tubing joint sealing face, torque table shoulder and thread is obtained. In order to compare the characteristics of special threaded joints, the API tubing joints of the same size were analyzed by finite element method. The results show that the stress distribution of the sealing surface of the special thread joint, the shoulder of the torque table and the part of the thread is reasonable when the optimum torque is up, and if the axial tensile force is greater than 400 kN, the stress concentration of the thread at both ends of the joint is produced, and the adhesive buckle is easy to occur here. When the internal pressure reaches 80 MPA, the equivalent stress of the sealing surface exceeds the yield strength of the material, so the joint can keep the sealing effect. If the internal pressure continues to increase, the part of the tube will yield first. Under the action of upper buckle and internal pressure load, the contact pressure and equivalent stress distribution of API oil pipe joints are both high at both ends and low in the middle, and if the internal pressure is greater than 40 MPA / a API joints, the stress concentration at both ends of the joints is obvious, and the adhesive buckling or yield failure is easy to occur here. Based on the structural analysis and finite element analysis of special threaded joints, combined with relevant standards and literature, this paper gives the recommended method of selecting special threaded joints, and gives the performance evaluation table of commonly used special threaded joints. It provides a reference for the selection of special threaded tubing joints.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH131.3

【参考文献】