An apparatus for multisensor electromagnetic defectoscopy and integrity monitoring of well casings

An apparatus for defectoscopy of downhole casings, which comprises an electromagnetic field generation unit, pick-up sensor unit, and data acquisition and processing unit, all these units being mounted in a housing, and, specifically:

• Electromagnetic field generation unit for generation of excitation pulse of specified amplitude and duration is essentially an exciter coil containing a core made of a material with a high magnetic permeability;
• Pick-up sensor unit comprises an integral pick-up coil and a plurality of radial pick-up coils mounted around the exciter coil winding, with each pick-up coil having a U-shaped core poles directed perpendicularly to the surveyed pipe surface and centre line of the winding is parallel to the centre line of the exciter coil winding;
• Data control, acquisition and processing unit comprises a plurality of operational amplifiers with variable amplification factors and analogue-to-digital converters (ADC) that transmit signals from pick-up coils to microcontroller connected to a PC with casing defect analysis software installed. The microcontroller controls the electromagnetic field generation unit, amplification factors and ADC.