Patent ID: 8113300
Filing Date: 2012-02-14
Classification: E21B

Abstract:
1. A system for excavating a borehole through a subterranean formation comprising: a supply of pressurized fluid mixed with impactors whose mean diameter is between 0.075 inches and 0.100 inches of a substantial portion by their weight; a drill string in a borehole in communication with the pressurized fluid mixed with impactors; a drill bit disposed on a lower end of the drill string; nozzles disposed on the bit that direct the supply of pressurized fluid mixed with impactors from the drill string into excavating contact with the borehole; and a first junk slot defined between a lateral side of the drill bit and a surface of the borehole, wherein the nozzles have an orientation configured so that impactors directed into excavating contact rebound from the borehole through the junk slot to avoid erosion of the drill bit.