塔里木油田钻柱转换接头失效原因分析及预防

Failure Analysis and Prevention on Drill Stem X-Qver Subs in Tarim Oilfield

对塔里木油田2006年1—5月发生的钻柱转换接头失效事故进行了分析研究,对失效的钻柱转换接头尺寸进行了测量,对钻柱转换接头断口形貌进行了宏观分析,发现钻柱转换接头断裂位置都在外螺纹接头危险截面上。通过分析计算认为,钻柱转换接头断裂原因与外径不符合标准及内、外螺纹接头弯曲强度比不合理有关。对钻柱转换接头刺漏形貌分析结果认为,刺漏与接头密封能力不足有关。进一步调查研究发现,钻柱转换接头失效与没有严格执行SY/T5200行业标准和API SPEC 7标准有一定关系。在调查分析的基础上,对如何防止或减少钻柱转换接头失效事故提出了有效的预防措施。

This paper gives a thorough analysis of failure accidents of drill stem X-over subs occurred from January to May in 2006 inTarimOilfield. It found that the fracture positions of drill-stem subs are all at pin sections based on dimension measure and analysis of the fracture sections, h shows that the frac- tures of drill-stem subs are ascribed to outside diameter and the irrational bend strength between inside and outside threads. The leakage is caused by insufficient seal capability of drill-stem subs based on the analy sis of leakage morphology. The failure accidents of drill-stem subs are related to not carrying out SY/T 5200 and API SPEC 7 standards. Some suggestions are provided in order to prevent drill-stem subs failure.