Patent ID: 6489772
Filing Date: 2002-12-03
Classification: G01V

Abstract:
A borehole induction coil transmitter comprising:an enclosed casing adapted to be positioned in a borehole; a core positioned in and enclosed by said casing and composed of material selected from the group consisting of ferrite and mu-metal; said core having a coil of electrically conductive material wrapped there around; said coil being composed of a wrapping of a wire composed of said electrically conductive material, such that the wire wrapping is selected from the group of even spaced wraps along a length thereof, and even spaced wraps along a portion of the length with more closely spaced wraps near the ends thereof; an array of capacitors positioned in and enclosed by said casing and connected in series with said coil of electrically conductive material to tune the coil to a resonant frequency; a flux monitor positioned in and enclosed by said casing including a wire winding around a central section of said coil; a current driver positioned in and enclosed by said casing for driving the transmitter at the resonant frequency; and means connected to said enclosed casing and adapted to retain said enclosed casing in an associated borehole.