煤层气开发用加厚油管螺纹接头损伤失效分析

Failure Analysis on Damage of Upset Tubing Threaded Connections Used for Coal-bed Gas Development

针对煤层气开发用2-7/8″(73.02mm)加厚油管在试气施工时通、洗井后出现螺纹接头严重损伤的情况,对油田现场使用工况和操作进行了调查分析,对损伤接头的外观、化学成分、力学性能和显微组织进行了分析,并抽取同批次加厚油管进行螺纹参数检测。结果表明:现场拧接操作不当是造成油管螺纹接头损伤的主要原因,并据此提出了油管现场安全使用的建议。

The threaded connections of 2-7/8″ （73.02 mm） upset tubing used for coal-bed gas development were seriously damaged after passing and washing well in gas production test. The oil field service condition and operation were surveyed and diagnosed. The extrinsic feature, chemical compositions, mechanical properties and microstructure of the failure connections were analyzed. The same hatch upset tubing＇s thread parameters were inspected. The results show that the misoperation of make-up was the main reason for the damage failure of the threaded connections, and some suggestions were put forward for safe use of tubings.