Drilling Stick-Slip Problem & Mitigation
Stick-slip torsional drill string vibrations manifest in low-frequency torque fluctuations of significant amplitude during drilling or coring operations. It is often seen as a groaning noise emanating from the top drive or rotary table. The period of oscillation is typical of the order of 2-10 seconds. This period corresponds to the first eigenfrequency of the drill string/BHA combination, the so-called ‘torsional pendulum mode’.
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