2015 EJRNL PP LIPING TANG 1.pdf
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Terbatas Suharsiyah
» ITB
Terbatas Suharsiyah
» ITB
Stick-slip vibration presents one of the major causes of drilling problems, such as premature tool
failures, low drilling efficiency and poor wellbore quality. The objective of this work is to investigate
the influences of rotary table speed (RTS) on stick-slip phenomenon of the drilling system. In this
study, the drilling system is treated as a lumped torsional pendulum model of which the bit/rock
interaction is regarded as Coulomb friction. By analyzing cases with different RTS, two types of
vibrations on the bit are found: stick-slip vibration and uniform motion. With an increase in the
RTS, the stick-slip vibration on the drill bit disappears once the RTS arrives at its critical value. For
the cases that stick-slip vibrations occur, the phase trajectories converge toward a limit cycle. For
the cases that stick-slip vibration does not appear, the drill bit tends to stabilize at a uniform motion
and the phase trajectories correspond to contracting spirals observed in the phase plane.