Patent ID: 6129161
Filing Date: 2000-10-10
Classification: E21B

Abstract:
A rotary drill bit for drilling a borehole into the earth comprising a bit body having a leading face and a gauge region, a plurality of cutting elements mounted on the bit body, a plurality of blades formed on the leading face of the bit, a plurality of axially extending kickers formed on the outer extremities of a plurality of said blades providing part-cylindrical bearing surfaces which, in use, bear against a wall of the borehole, a plurality of fluid channels between said blades extending outwardly away from the bit axis across said leading face and towards the gauge region, and a plurality of nozzles for supplying fluid to said channels, there being provided at the outer end of at least one of said channels, in the gauge region, an outwardly facing junk slot which extends across only a part of the width of the channel, and an additional bearing surface adjacent to said kickers which also extends across only a part of the channel and which, in use, also bears against the wall of the borehole, there being provided in said channel, inwardly of the gauge region, an opening into an enclosed passage which passes internally through the bit body to an outlet.