磨损套管螺纹接头密封面力学特性

螺纹接头磨损是影响套管密封完整性的主要原因之一。由于套管螺纹接头结构特征复杂，常规计算模型无法得到解析解，实验研究也较困难，因此针对磨损条件下接头密封面力学特性的研究很少。鉴于此，建立了均匀磨损、偏心筒型磨损和月牙型磨损3种磨损形式的套管螺纹接头三维弹塑性有限元模型，基于ABAQUS软件分析了磨损深度为5 mm时套管螺纹接头在复杂载荷条件下的应力应变特征，研究了上扣扭矩、轴向拉力和弯矩作用下3种磨损形式对套管螺纹接头密封面力学特性的影响。研究结果表明，均匀磨损套管螺纹接头的密封面上存在较大塑性应变，且接触力比其他磨损形式大，密封失效风险较高。偏心筒型和月牙型磨损使得套管螺纹接头密封面接触面积、环形密封带最窄处接触宽度都有所降低，增加了接头局部漏失风险，影响套管螺纹接头的密封可靠性。

Mechanical properties of the sealing surface of worn casing threaded connection

Wearing of threaded connection is one of the main reasons that affect the seal integrity of casing. Due to the complex structural features of casing threaded connection, analytical solutions cannot be obtained, and relevant experimental studies are also difficult to conduct. For this reason, there were few studies on the mechanical properties of the sealing surface of threaded connection under wear conditions. In view of this, this paper established a three-dimensional elastic-plastic finite element model of casing threaded connection with uniform wear, eccentric wear and crescent wear. The ABAQUS was used to analyze the stress-strain characteristics of casing threaded connection under complex load conditions when the wear depth is 5 mm, and study the influence of three wear forms on the mechanical characteristics of the sealing surface of casing threaded connection under make up torque, axial tension and bending moment. The results show that there is a large plastic strain on the sealing surface of casing threaded connection under the condition of uniform wear, and the contact force on its sealing surface is greater than that under other wear conditions, that is, uniform worn casing threaded connection has a greater risk of seal failure. The contact area of the sealing surface of the casing threaded connection with eccentric and crescent wear is small, as well as the contact width of the narrowest part of the circular seal belt, which has a large influence on the sealing reliability of casing threaded connection.