Abstract: A method for finding the position of a drill bit working at the bottom of a borehole comprising sending ultrasonic energy down the drill stem, recording the energy radiated from the drill bit through the earth to an array of geophones around the wellhead on the surface, and calculating the distance from the drill bit to each geophone. The drilling mud surrounding the drill stem absorbs the slight amount of ultrasonic energy that escapes laterally so that substantially all of the effective signal is generated at the bottom of the hole where the drill bit is working.
Abstract: A sonic generator sends a collimated acoustical wave into the section of earth under test and resonance conditions are established depending upon the nature and depth of discontinuities in the path of the acoustical wave. These resonance conditions are monitored by observing and recording electrical relationship in the power supply section of the sonic generator.