某油井在起甩管柱时第329根修复油管发生断裂。通过化学成分分析、力学性能测试、断口宏微观分析、金相检验以及受力分析等方法, 对该油管的断裂原因进行了分析。结果表明: 该油管为过载断裂, 油管管壁因修复过程及均匀腐蚀减薄严重, 使其承载能力大大降低, 从而导致其在提升过程中的较大载荷作用下发生过载拉伸断裂。

In an oil well, the 329th repair tubing fractured during throwing the string. By means of chemical compositions analysis, mechanical properties test, macro and micro fracture analysis, metallographic examination and force analysis, the fracture reason of the tubing was analyzed. The results show that the tubing was overload fracture. Because the tubing wall thickness was thinned seriously due to repair process and uniform corrosion, the bearing capacity of the tubing reduced greatly, which resulted in the tensile overload fracture of the tubing under the action of large load during throwing.