A Modal Approach for Chaotic Vibrations of a Drillstring Conference Paper uri icon


  • The purpose of this paper is to present a methodology to predict vibrations of drilllstrings for oil recovery service. The paper extends a previous model in the literature to include drill collar flexibility utilizing a modal coordinate condensed, finite element approach. The nonlinear effects of drillstring / borehole contact, friction and quadratic damping are included. Bifurcation diagrams are presented to illustrate the effects of speed, friction, stabilizer gap and drill collar length on chaotic vibration response. A study is conducted on factors for improving the accuracy of Lyapunov Exponents to predict the presence of chaos. This study considers the length of time to steady state, the number and duration of linearization sub-intervals, the presence of rigid body modes and the number of finite elements and modal coordinates. The results may be helpful for computing Lyapunov exponents of other types of nonlinear vibrating systems with many degrees of freedom.

name of conference

  • ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference

published proceedings

  • Volume 1: 22nd Biennial Conference on Mechanical Vibration and Noise, Parts A and B

author list (cited authors)

  • Mongkolcheep, K., Palazzolo, A., Ruimi, A., & Tucker, R.

citation count

  • 2

complete list of authors

  • Mongkolcheep, Kathira||Palazzolo, Alan||Ruimi, Annie||Tucker, Randall

publication date

  • January 2009