ELECTROMAGNETIC BOREHOLE DEFECTOSCOPE Russian patent published in 2009 - IPC E21B47/00 

FIELD: oil and gas production.

SUBSTANCE: invention relates to geophysical investigations in wells and can be used for exposure and classification of defects of operational and protecting strings, oil-well tubing in oil and gas wells. Electromagnetic borehole defectoscope contains casing, electronics block, exciter coil of probe inductance, axis of which match to axis of well, and not less than three exploring inductance coils, located by perimetre of probe with magnetic axis, directed perpendicularly to axis. Magnetic axis of exciter inductance coil, excited by feeding of recurrent pulses with specified duration, directed lengthwise probe. Electronics block is implemented with ability of digital recording of electromotive difference of transients of exploring coils, as functions of time in range 1÷100 ms, that provides azimuthal and radial resolution.

EFFECT: increasing informativity of measurements ensured by ability of discharge of defects by different walls of strip, separation of defects on inner and external surface, and also increasing of sensitiveness to little defects.

7 dwg