Drill bit location, guidance by seismic seen feasible : Katz, L J Oil Gas J, V78, N30, 28 July 1980, P197–200

Abstract

For continuously locating an underground rotary drill bit, a seismic method of monitoring the bit's acoustical emissions (in a manner similar to that used for earthquake detection) has proved feasible in a 7-day experiment: the seismic technique placed the drill bit at the same deviation angle as that found by a conventional survey and provided the azimuthal direction as well; during drilling, a large signal (70-100 db above the background noise) was generated at 22 Hz; and the array of eight stations, each comprising a 12-geophone string directed radially to the drill rig, revealed a correlation value of 0.41 (about 40 times the background level), indicating that a coherent signal was being recorded. A DFS III digital acquisition system collected the data at a 4-ms sampling rate. Compared with lowering directional-surveying equipment into the borehole, the seismic method is less time-consuming and less expensive.