中文摘要：

某井在油管提升过程中,发现位于紧接油管挂下端的88.90mm×6.45mm油管短节发生断裂。通过宏观检验、化学成分分析、力学性能检测、显微组织分析、宏观和微观断口分析,对该油管短节的断裂原因进行了分析。结果表明：该油管短节为过载断裂,断裂的原因是油管短节外螺纹端的设计拉伸余量偏低,同时螺纹加工存在偏心,使油管短节的承载能力有一定程度的下降。

英文摘要：

During the process of pulling the oil pipes in one well,it was found that the tubing joint（88.90mm×6.45mm）in lower end of tubing hanger had fractured.The fracture reasons of the tubing joint were analyzed by means of macrographic examination,chemical composition analysis, mechanical property test,microstructure analysis,macro and micro fracture analysis.The results show that the fracture type of the tubing joint was overload fracture.The fracture reason was that the designed tensile margin of external thread of the tubing joint was relatively low.Meanwhile,the eccentricity existed in the thread processing of the tubing joint,leading to a certain decline of the bearing capacity of the tubing joint.