3828867 is referenced by 81 patents and cites 9 patents.

An earth drill bit locating apparatus and method of detecting and locating the position of a drill bit below the surface of the earth utilizing very low frequency electromagnetic energy. The apparatus includes a transmitter located adjacent the drill bit for transmitting a very low-frequency electromagnetic wave below 5,000 Hz and a plurality of receivers including antennae placed adjacent to the earth's surface for detecting the low-frequency wave and computing the position of the drill bit by triangulation. Each receiver is a directional indicating receiving means for obtaining raw data in order to display and plot the movement of the drill head as it moves into the earth. The transmitter is powered by an alternator driven by a turbine in the mud supply conduit or collar just above the bit. The drill collar is fitted with electrodes or wire loops which are connected to the transmitter output to cause the drill collar to act as an electric or magnetic radiating dipole.

Low frequency drill bit apparatus and method of locating the position of the drill head below the surface of the earth
Application Number
Publication Number
Application Date
May 15, 1972
Publication Date
August 13, 1974
Elwood Albert A
Malin & Haley
E21b 47/24
G01V 15/00
G01S 01/02
G01S 01/00
E21B 47/00
E21B 47/04
E21B 41/00
E21B 47/09
E21B 07/04
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