INDUCTIVE MEASUREMENTS UNDER DECREASED BOREHOLE EFFECT Russian patent published in 2009 - IPC G01V3/26 

FIELD: electricity, mining.

SUBSTANCE: induction instrument comprises conducting core, at least one sound having transmitter, compensating coil and receiver which are placed in the insulating casing of the instrument, the casing encloses the conducting core and electrode mounted on the instrument insulating casing at the chosen place between the compensating coil and the receiver. The chosen place is spaced from the transmitter at the distance approximately corresponding to the harmonic average of distance between the transmitter and the compensating coil and the distance between the transmitter and the receiver. The electrode comprises contact which forms a conductive path to the conducting core. Additional electrodes can be mounted above and below each transmitter and receiving coil to decrease sensitivity to the instrument decentering in the borehole.

EFFECT: decreasing susceptibility to influence of instrument decentering in borehole.

18 cl, 23 dwg