Abstract: A drill bit with a housing and roller cones has a high-speed fluid jet erosion system utilizing dual discharge, high-velocity, jet streams that is directed at the surface to be eroded. The jet streams are developed from a dual discharge nozzle adapted to form a first, swirling liquid jet and a second, axial liquid jet in combination therewith. When used in a shale-like formation, the bit includes a nozzle in a bowl area of the housing that sends a vortex shaped spray against the roller cones.

Abstract: A high-speed fluid/mechanical jet erosion system utilizing a high-velocity, jet stream discharged contiguous the surface to be cut. The jet stream is developed from a single plenum flow system adapted to merge and enhance the erosive high-speed fluid jet characteristics of fluid with cavitational collapse erosion. The system further includes a tapered drill bit housing, with mechanical cutters therealong which places a generally axially centered, exiting jet immediately against the target formation, providing maximum mechanical and fluid energy transfer to the formation.