φ88.90mm×6.45mm特殊螺纹接头接箍变形分析

Cause Analysis on Coupling Deformation of φ88.90mm×6.45mm Premium Connection

对某井φ88.90mm×6.45mm特殊螺纹接头接箍变形原因进行了系统调查和失效分析。通过尺寸测量、力学性能试验和全尺寸实物试验,认为吊卡磨损引起接箍端面偏斜承载是导致事故的主要原因。该油管产品属于特殊产品,虽然也属于常用品种,但由于采用非API标准较小接箍设计,减小了接箍端面与吊卡的接触面积,不利于现场操作,是此次事故的次要原因。

An investigation and failure analysis on coupling deformation of φ88.90mm×6.45 mm tubing are given.The failure analysis contents include dimension measure,mechanical property test,and full-scale test.It is considered that the main cause for coupling deformation of φ88.90mm×6.45 mm tubing is the coupling end deflection caused by elevator wear.The tubing product belongs to special product and also belongs to common varieties.The tubing coupling is designed with non API standard coupling outer diameter which reduces the contact area of the coupling end and the elevator.The tubing product is not convenient to operate.That is the secondary cause of the accident.