TY - JOUR
T1 - A simplified model to explore the root cause of stick-slip vibrations in drilling systems with drag bits
AU - Richard, Thomas
AU - Germay, Christophe
AU - Detournay, Emmanuel
PY - 2007/8/21
Y1 - 2007/8/21
N2 - In this paper a study of the self-excited stick-slip oscillations of a rotary drilling system with a drag bit, using a discrete model that takes into consideration the axial and torsional vibration modes of the system, is described. Coupling between these two vibration modes takes place through a bit-rock interaction law, which accounts for both the frictional contact and the cutting processes. The cutting process introduces a delay in the equations of motion that is responsible for the existence of self-excited vibrations, which can degenerate into stick-slip oscillations and/or bit bouncing under certain conditions. From analysis of this new model it is concluded that the experimentally observed decrease of the reacting torque with the angular velocity is actually an expression of the system response, rather than an intrinsic rate dependence of the interface laws between the rock and the drill bit, as is commonly assumed.
AB - In this paper a study of the self-excited stick-slip oscillations of a rotary drilling system with a drag bit, using a discrete model that takes into consideration the axial and torsional vibration modes of the system, is described. Coupling between these two vibration modes takes place through a bit-rock interaction law, which accounts for both the frictional contact and the cutting processes. The cutting process introduces a delay in the equations of motion that is responsible for the existence of self-excited vibrations, which can degenerate into stick-slip oscillations and/or bit bouncing under certain conditions. From analysis of this new model it is concluded that the experimentally observed decrease of the reacting torque with the angular velocity is actually an expression of the system response, rather than an intrinsic rate dependence of the interface laws between the rock and the drill bit, as is commonly assumed.
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U2 - 10.1016/j.jsv.2007.04.015
DO - 10.1016/j.jsv.2007.04.015
M3 - Article
AN - SCOPUS:34447523409
VL - 305
SP - 432
EP - 456
JO - Journal of Sound and Vibration
JF - Journal of Sound and Vibration
SN - 0022-460X
IS - 3
ER -