SEW J55 钢级LC套管螺纹连接质量影响因素探讨

为了进一步分析SEW J55 LC套管螺纹连接质量的影响因素以及套管发生异常脱扣失效的原因，以Φ139.7 mm×7.72 mm SEW J55 LC套管为例，从套管使用工况、螺纹加工参数、拧接扭矩控制等方面进行了试验研究。结果显示，SEW套管在弯曲状态拉脱试验、螺纹参数极限匹配下拉脱试验的拉脱载荷均高于API TR 5C3标准要求。研究表明，按照内控标准生产加工的SEW套管满足标准要求，弯曲工况、螺纹加工工艺、存放时间和J值均不是套管异常脱扣失效的原因。为提升SEW J55 LC套管螺纹连接质量，预防套管在油田使用中出现异常反拧退扣，建议将拧接扭矩在推荐标准基础上增大10％执行。

Discussion on Influencing Factors of SEW J55 LC Casing Thread Connection Quality

In order to further analyze the influencing factors of thread connection quality of SEW J55 LC casing and the cause of abnormal tripping failure of casing, taking Φ139.7 mm × 7.72 mm SEW J55 LC casing as an example, the test research is carried out from the aspects of casing service conditions, thread processing parameters and screw torque control. The results show that the pull-out load of SEW casing in bending state and thread parameter limit matching pull-out test are higher than the requirements of API TR 5C3 standard. The study indicate that the SEW casing produced and processed according to the internal control standard meets the requirements of the standard, and the bending condition, thread processing technology, storage time and J value are not the causes of casing abnormal tripping failure. In order to improve the quality of SEW J55 LC casing thread connection and prevent abnormal reverse screwing and thread withdrawal during casing application in oilfield, it is recommended to increase the screw-on torque by 10% on the basis of the recommended standard.