Imbalance compensated drill bit.

摘要

An imbalance compensated drill bit (10) is disclosed that takes advantage of undesired and destructive imbalance forces to prevent bit whirl. Methods of designing and making such imbalance compensated drill bits are disclosed whereby a drill bit body (12) has at least one cutting zone with a plurality of cutting elements (18) extending therefrom and at least one bearing zone (20). The bearing zone has a relatively smooth surface and is located at a position where the net imbalance force (from the cutting elements) is directed towards. When the drill bit is rotated, the imbalance force presses the bearing zone against the borehole wall, and the bearing zone slips along the wall, thereby preventing the center of rotation to shift and create the destructive whirling motion.