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COBEM 2019
25th International Congress of Mechanical Engineering
THE EFFECTS OF LATERAL-TORSIONAL COUPLING IN DRILL-STRING DYNAMICS
Submission Author:
Lucas Passos Volpi , RJ
Co-Authors:
Lucas Passos Volpi, Daniel de Moraes Lobo, Thiago Ritto
Presenter: Lucas Passos Volpi
doi://10.26678/ABCM.COBEM2019.COB2019-1151
Abstract
Drill-strings are subjected to a variety of vibrational phenomena that affects the drilling process and often leads to efficiency loss and even premature failure. These vibrations can be classified into axial, torsional and lateral. Although each dynamic can be modeled separately, the coupling between them can significantly affect the system response. In this paper, the effects of the coupling between lateral and torsional dynamics are discussed. The governing equations are obtained assuming a lumped parameter model for both lateral and torsional dynamics. The former considers the BHA an unbalanced rotor surrounded by a fluid annulus with discontinuous impact mechanics. The latter models the drill-string as a torsion pendulum with bit-rock interaction. Simulations regarding uncoupled and coupled dynamics shows that torsional vibrations, such as stick-slip oscillations, governs the BHA lateral behavior and can induce lateral vibrations.
Keywords
drill-string, Lumped parameter model, stick-slip, Whirling Frequencies
