Patent ID: 7802640
Filing Date: 2010-09-28
Classification: E21B,Y10T

Abstract:
1. A rotary drill bit for forming a wellbore, comprising: a bit body having an upper portion adapted for engagement with a drill string for rotation of the bit body; a number of cutting structures engaged with the bit body a fluid cavity formed in the bit body and sized to receive drilling fluid from an attached drill string; a plurality of fluid flow passageways extending from the cavity to respective nozzles engaged with exterior portions of the bit body; each nozzle having a nozzle body with a fluid flow passageway extending between an inlet portion and an outlet portion of the nozzle body; a first Coanda surface disposed within the fluid flow passageway adjacent the outlet portion; the first Coanda surface configured to direct a fluid stream from the nozzle body in a desired direction; and a second Coanda surface disposed outside the fluid flow passageway adjacent to and extending from the first Coanda surface.