Parametric studies on drill-string motions

Chien Min Liao, Nicholas Vlajic, Hamad Karki, Balakumar Balachandran

Research output: Contribution to journalArticlepeer-review

60 Scopus citations


Experimental and numerical investigations are conducted into drill-string motions. The numerical efforts are carried out by using a reduced-order model with attention to stickslip interactions between a drill string and an outer shell. These efforts are complemented by experimental studies conducted with a unique, laboratory scale model. Qualitative and quantitative changes in the system behavior are studied with respect to the rotation speed and mass imbalance. Comparisons are made between the numerical findings and the corresponding experimental results. In addition, the influence of contact conditions between the drill string and the outer shell on the drill-string dynamics is also examined. The findings of the work suggest that small changes in the system rotation speed can have a significant influence on the nature of drill-string motions and they also provide guidelines for steering the system out of regions of undesirable dynamics and maintaining drill-string motions close to the center of a borehole.

Original languageBritish English
Pages (from-to)260-268
Number of pages9
JournalInternational Journal of Mechanical Sciences
Issue number1
StatePublished - Jan 2012


  • Drill string
  • Mass imbalance
  • Reduced-order model
  • Stickslip interactions


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