空气钻井钻柱疲劳断裂计算分析

Calculation and Analysis of Drill Stem Fatigue Failure in Air Drilling

在现场调研空气钻井钻柱断裂现象的基础上,利用目前断裂力学较成熟的理论和试验数据对钻柱疲劳失效进行了分析计算。简述疲劳裂纹的特点及形成,对裂纹扩展速率的影响因素,即,应力变化量、裂纹长度、温度、过载峰进行分析,并对钻杆裂纹不扩展的临界转速及临界钻压进行计算,得出一些防止钻柱过早疲劳失效的参考结论。建议现场技术人员应高度重视钻具的使用和管理,坚持钻具定期探伤,同时尽可能使用优质钻杆和钻铤。

Drills stem break phenomenon in the scene investigation and study air drilling in the foundation,the use present fracture mechanics mature theory and the empirical datum to drill the column fatigue failure to carry on the analysis computation. Summarizes the fatigue cracking characteristic and the formation, to crack growth fate＇s influencing factor stress variation quantity, the crack length, the temperature, the overload peak carries on the analysis, and the critical rotation speeds which and the critical bit pressure does not expand to the drill rod crack carry on the computation,obtains some to prevent to drill the column premature fatigue failure the reference conclusion. It was thought that the scene technical personnel should take drilling tool＇s use and the management, and insisted that the drilling tool regular crack detection, simultaneously as far as possible uses the high quality drill rod and the drill collar.