A method to detect the relative position of a drill bit with respect to a coal seam boundary using an electric-field borehole telemetry apparatus, that includes the steps: providing a measure-while-drilling apparatus that includes inclination sensors, directional sensors, logging sensors of choice and...http://www.google.fr/patents/US8044819?utm_source=gb-gplus-shareBrevet US8044819 - Coal boundary detection using an electric-field borehole telemetry apparatus
Coal boundary detection using an electric-field borehole telemetry apparatus
