Stick Slip

A sudden jump in velocity from standstill as a reaction to built-up torsional energy along the length of the drill string. While ‘stuck’, the bit stops drilling but torque continues to be applied from the turning rotatory table on the rig floor. The build-up of torque causes the bit to giveaway and ‘slip’, resulting in a significant increase in rotational speed. Vibrations are sent along the drill string, which can cause damage.