膨胀套管螺纹联接设计研究

鉴于API标准套管螺纹及目前广泛使用的特殊螺纹无法满足膨胀套管的技术要求等问题,设计出内外壁都与管体平齐的直联型膨胀套管螺纹联接。对设计进行了计算机有限元模拟分析,采用大型非线性有限元分析软件MSC.Marc,将膨胀套管螺纹联接按轴对称问题处理,选用轴对称节点四边形实体单元。模拟分析表明,设计的螺纹在上扣过程中,其等效VME应力分布呈现啮合螺纹端部较高、中间部分较低的趋势,最大值约为271 MPa,符合膨胀套管螺纹的基本要求,膨胀后的结构及密封性能满足现场要求。

Design study of thread connection of inflatable casing

Since the API standard casing thread and the widely-used special thread cannot meet the demand of the inflatable casing,the extreme-line casing thread connection whose inner wall and outer wall are in parallel with the tubular body is designed.The computational finite-element simulation analysis is carried out.By using the large nonlinear finite-element software MSC-Marc,the thread connection of the inflatable casing is handled according to axial symmetry and the axi-symmetrical node quadrangle solid unit is chosen.The simulation analysis shows that during the threading of the designed thread,the distribution of VME stress shows the tendency of higher engaging thread end and lower middle part with maximum value of 271 MPa,which conforms to the basic demand of inflatable casing thread.The expanded structure and sealing performance meet the field demand.