极限工况下钻杆接头疲劳分析

近年来,超深井、大位移井的数量持续增加,钻进时钻杆失效问题也越来越多。针对钻杆失效问题,进行了极限工况下的钻杆接头疲劳分析。分析结果表明:超深井及大位移井钻探时,采用高抗扭结构钻杆,相比常规钻杆,整体寿命延长86%,最大应力减小8. 3%;采用高抗弯结构钻杆,相比常规钻杆,整体寿命延长652%,最大应力减小8. 6%。通过合理调整转速和钻压,可以延长钻杆的疲劳周期,提高安全因数。

Fatigue Analysis of Drill Pipe Joint under Extreme Conditions

In recent years,the number of ultra deep wells and extended reach wells has continued to increase,and drill pipe failure has become more and more serious during drilling.Aiming at the drill pipe failure,fatigue analysis of the drill pipe joint under extreme conditions was carried out.The analysis results show that when drilling ultra deep wells and extended reach wells,if high torsional structure drill pipe is adopted,compared with the conventional drill pipe,the bulk life time can be extended by 86%,the maximum stress can be reduced by 8.3%.Compared with the conventional drill pipe,with the drill pipe in high bending resistance structure,the bulk life time can be extended by 652%,the maximum stress can be reduced by 9.1%.By rational readjustment of the rotation speed and bit load,the fatigue cycle of the drill pipe can be extended and the safety factor can be improved.