The wall thickness and ovality of a tubular are simultaneously determined.
The theoretical radius of a pipe is computed from a measurement of its
circumference. An ultrasonic device conventionally used to measure the
wall thickness of tubulars is adapted to also measure the maximum and
minimum diameters and ovality by equipping or utilizing existing
ultrasound inspection device with contact surfaces which contact the
tubular at a fixed distance apart and at a known distance from the
surface of the ultrasonic transducer. The contact surfaces define a chord
of known length on the tubular under test. The mean radius of the tubular
may be computed from multiple water path measurements around the
circumference relative to a known fixture. The maximum and minimum
diameter and ovality are calculated from the measured differences in
distance from the surface of the tubular to the ultrasonic transducer and
the theoretical circle. Wall thickness and ovality may be correlated
relative to position by using the same apparatus for both measurements.