Patent ID: 6065553
Filing Date: 2000-05-23
Classification: E21B

Abstract:
A drag-type drill bit for drilling holes in subsurface formations comprising a bit body having an end face and a shank for connection to a drill string, a plurality of blades upstanding from the end face of the bit body and extending radially outwardly away, a plurality of cutting elements mounted on each blade, and a plurality of nozzles in the bit body for delivering drilling fluid to the end face thereof for cooling and cleaning the cutters, said blades including a plurality of primary blades which, at their outer ends, are spaced apart around a peripheral gauge portion of the bit, and a plurality of secondary blades spaced circumferentially between the adjacent primary blades, each secondary blade having an outer end which terminates at a location adjacent to the outer periphery of the bit body and inwardly of the gauge portion of the bit.