Stick-slip is a destructive drilling dysfunction where the drill bit alternately stops rotating and suddenly accelerates, reducing rate of penetration by up to 50% and causing premature equipment failure. This severe torsional vibration pattern can occur at frequencies of 0.1-2 Hz, with bit speed varying from zero to 2-3 times the applied rotary speed, creating extreme stress concentrations in drilling equipment.

The mechanism develops when friction between the bit and formation creates torque variations that the drill string cannot dampen effectively. As the bit encounters harder rock or increased contact force, torque spikes wind up the drill string like a torsion spring. When stored energy exceeds friction forces, the bit suddenly breaks free and over-rotates before sticking again, wasting energy in destructive oscillations rather than productive rock removal.

Stick-slip vibration is particularly problematic in hard rock drilling and high-angle wells where bit-rock interaction forces are high and drill string flexibility is limited. Advanced drilling systems can detect and mitigate stick-slip in real-time through downhole automation and optimized weight control, maintaining smooth bit rotation and optimal drilling performance even in the most challenging conditions.