不同工况下套管偏梯形螺纹连接的温度-应力耦合

摘要

偏梯形螺纹相比圆形螺纹不易产生滑扣, 在许多苛刻的井深结构中被广泛采用. 结合弹塑性力学以及有限元理论, 利用ANSYS软件建立了偏梯形螺纹接头的有限元模型, 对模型进行了不同工况下的温度-应力耦合分析, 分析了温度载荷对套管螺纹接头应力、 接触压力及接头附近位移的影响. 分析结果表明, 在螺纹接头两端轴向位移受约束的情况下, 温度载荷对接触面的Mises应力和接触压力影响显著, 两者均随温度载荷的升高而增大, 且在达到较高温度后增大趋势变缓; 偏梯形螺纹扣牙过盈接触时, 比较不同扣牙的Mises应力和接触压力, 呈现两端大、 中间小的趋势, 且在轴向受拉和受压工况下, 接头附近的位移变化十分明显.%The buttress thread is less likely to produce thread slipping compared to round thread and is widely used in many demanding wellbore configuration. Based on elastic-plastic mechanics and finite element theory, a fi-nite element model of buttress joint is established using ANSYS software to conduct temperature-stress coupling a-nalysis on the model under different working conditions. The effects of temperature load on the casing thread joint load, contact pressure and the displacement nearby joint have been analyzed. The results show that, in the case of constrained axial displacement of the thread joint at both ends, temperature load has a significant effect on Mises stress and contact pressure of the contact surface. With the increase of temperature load, both the Mises stress and contact pressure increase and then slow down after reach a higher temperature. When the buttress thread teeth expe-rience interference contact, the Mises stress and contact pressure of the middle teeth are larger than the teeth on ends. In axial tension and compression conditions, the displacement near the joint changes significantly.