钻杆振动特性分析及疲劳周期预测

Vibration Characteristics Analysis and Fatigue Cycle Prediction of Petroleum Drill Pipe

近年来随着深井、超深井数量持续增加,在钻井过程中,钻柱振动引起钻具失效的问题比较常见。运用ANSYS软件模拟了钻柱在钻井液条件下的振动过程;这次分析在一定程度上反映井下钻柱工作状态,为钻柱的随钻控制研究提供理论基础。结果表明:钻杆在44. 620 2 r/min的转速位置振动破坏最大,比不考虑钻井液影响下转速降低了15. 9 r/min。根据钻柱振动信号的频域分析,给定40~80 r/min的转速范围,钻杆的疲劳周期为3. 107×10~7s;并且随着钻进深度的增加,不同钻柱振动位置逐渐接近并发生重合,引起的共振破坏显著增加,与实际井深的变化所引起共振现象十分吻合。

In recent years,as the number of deep wells and ultra-deep wells continues to increase,the problem of drill string failure often causing drill failure during drilling is common. The ANSYS software was used to simulate the vibration process of the drill string under drilling fluid conditions. This analysis reflects the working state of the drill string to some extent and it provides a theoretical basis for the drilling while drilling control research. The results show that the vibration damage of the drill pipe is the highest at the speed of 44. 620 2 r/min,which is 15. 9 r/min lower than that of the drilling fluid. According to the frequency domain analysis of the vibration signal of the drill string,the fatigue period of the drill pipe is 3. 107 × 10~7 s given the range of speed from 40 r/min to 80 r/min. With the increase of the drilling depth,the vibration positions of different drill strings are gradually approaching. Coincidence occurs and the resulting resonance damage will increase significantly,which is in good agreement with the resonance phenomenon caused by the change of the actual well depth.