Contact or proximity pad mounted sensor system for imaging cavity defects and delamination defects between layers in multilayered cylindrical structures in subsurface wells

A method for inspecting a well having a nested multi-tubular structure, the method comprising:

• generating a signal pulse having a plurality of frequencies using a signal generator;
• modifying the signal pulse by applying at least one of amplitude modulation and frequency modulation using a signal shaper to provide a drive signal;
• transmitting an acoustic signal based on the drive signal into an inner-most tubular of the nested multi-tubular structure using an acoustic transducer coupled to a mandrel configured to be conveyed in the inner-most tubular, the acoustic transducer being configured to transmit the acoustic signal and receive a return acoustic signal having a plurality of resonances due to the nested multi-tubular structure;
• transitioning an acoustic impedance between the acoustic transducer and the inner-most tubular using an acoustic transition impedance matching material disposed on a sensing face of the acoustic transducer;
• receiving the return acoustic signal having the plurality of resonances using the acoustic transducer;
• determining an annulus distance of any tubular in the nested multi-tubular structure with respect to an adjacent tubular using a time of flight of the transmitted acoustic signal;
• determining an acoustic speed in a component in the nested multi-tubular structure using the annulus distance and the plurality of resonances;
• and
• determining a characteristic of the component that corresponds with the acoustic speed.