Patent ID: 6092613
Filing Date: 2000-07-25
Classification: E21B

Abstract:
A rotary drill bit for connection to a drill string and for drilling boreholes in subsurface formations comprising:a bit body having a leading face and a gauge region;a plurality of cutting elements mounted on the leading face of the bit body;a plurality of fluid channels formed in the leading face of the bit body; anda plurality of nozzles mounted in the bit body for supplying drilling fluid to the channels for cleaning and cooling the cutting elements, wherein there is provided in at least one of said channels an opening into an enclosed passage which passes internally through the bit body to an outlet which, in use, communicates with the annulus between the drill string and the wall of the borehole being drilled, the gauge region of the drill bit comprising:a bearing surface which extends around substantially the whole of the gauge region, said bearing surface tapering inwardly as it extends away from the leading face of the drill bit.