Downhole buried utility sensing and data transmission system and method

Abstract

A downhole buried utility sensing and data transmission system for connection at the lower end of a drill string has sensors capable of detecting the existence of various different types of buried utilities and objects and making calculations as to the radial separation distance between the detected utilities and the drill head and transmitting data between the down hole drill head to the surface. The sensors respond to material properties used to construct the utility lines or the energy fields created by the operation of these lines (pipes and cables) or from the energy associated with transmission of the particular utility service, including sound energy resulting from fluid flow and electromagnetic energy from electric currents. The system can detect and distinguish the presence of ferromagnetic metallic objects including steel pipes and structures; non-metallic utility infrastructure including gas pipelines, concrete sewer lines, telecommunication lines, and cable systems outfitted with RF tracer lines and transmitters; energized AC and DC power cable systems; and determining the approximate range, relative azimuth, and elevation of the sensors relative to the detected utility or object. The system also supports automatic cessation of drilling operations by combining the warning information with microprocessor control of drill string rotation and thrust.