Ultrasonic imaging device and method for wells

A method for imaging a wellbore in a spiral wave imaging mode using a phased array ultrasonic radial imaging probe having an annular transducer array comprising a plurality of elements, the method comprising the steps of:

• a) pulsing a first element in the transducer array that forms part of a first sequence of elements;
• b) pulsing a next element that forms part of the first sequence of elements;
• c) repeating step b) for each element in the first sequence with a time delay between pulses to create a wave front that spirals radially outward from the transducer array in a clockwise or counterclockwise direction;
• d) receiving signals for each element in the first sequence;
• e) applying time delays to the received signals to achieve virtual beamforming and form imaging data;
• f) repeating steps a) to e) for additional sequences of elements in the transducer array;
• and
• g) coherently summing the imaging data from each sequence to form a 3D image of the wellbore.