Cavitating and Structured Jets for Mechanical Bits to Increase Drilling Rate—Part I: Theory and Concepts

Abstract

The erosion and cleaning effect of jets is enhanced when the degree of cavitation on or near the bottom of the hole is increased. Analyses indicate that self-excited, acoustically resonating nozzles, causing jets to be structured with large discrete vortex rings, should 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 effect hole cleaning in the absence of cavitation.