气密封特殊螺纹接头扭矩值理论研究

Theoretical study on torque value of premium connection

上扣扭矩是影响油田油套管上扣质量的最主要因素,带扭矩台肩的气密封特殊螺纹接头上扣扭矩由螺纹、密封面和台肩三部分叠加而成。根据厚壁圆筒理论,通过建立螺纹接头数理模型,推导出带扭矩台肩的气密封特殊螺纹接头扭矩计算公式。研究表明,螺纹过盈量偏差和台肩预紧力对最终扭矩值影响最显著。对精确测量的接头进行上扣试验,试验结果表明,该扭矩计算公式能准确反映实际上扣过程,为精确计算接头台肩扭矩拐点、最佳上扣扭矩和屈服扭矩提供了理论依据,对油气安全生产有很大的现实意义。

The make-up torque is the most important factor affecting the quality of oil casing and tubing.The torque of premium connection with torque shoulder is combined of three parts:thread,sealing surface and shoulder.According to the theory of thick-wall cylinder,the formula of connection with torque shoulder is deduced by establishing the mathematical model.The results show that the thread interference deviation and the shoulder force have the most significant impact to torque value.The experimental results show that this formula can accurately reflects the actual make-up process,it provides a theoretical basis for the precise control in connection making-up.It has a great practical significance for oil and gas production safety.