The Development Of Structured Cavitating Jets For Deep-Hole Bits

The erosion and cleaning effects of jets are enhanced when the degree of cavitation occurring on or near the bottom of the hole is increased. A new, STRuctured Acoustically Tuned Oscillating Jet (''STRATOJET'') system causes the formation of large discrete vortex rings that promote cavitation to depths several times greater than for conventional jets. The new nozzle designs are shown to be suitable for existing mechanical drill bits and may even enhance hole cleaning in the absence of cavitation. Recent data on the effect of drilling mud on the amplitude of excitation and some laboratory hole bottom cleaning results are also presented.