Laboratory experiments on ultrasonic logging through casing for barrier integrity validation

Abstract

Verification of annular barriers is essential for well integrity, with ultrasonic methods being central in well integrity testing for many decades. By doing ultrasonic pitch-catch measurements on a bench top laboratory setup developed to replicate an oil well casing, we were able to show that the beam width,-6dB, of the leaky Lamb wave propagating in the pipe widens only from 14 to 20.4 mm after 140mm of propagation in the pipe. This indicates that the excited Lamb wave has beam-like features, with litle spreading perpendicular to the propagation direction, hence, can be used to evaluate a limited area of the pipe. When introducing two pipes in the experimental setup, as an extension of a previously conducted simulation study by Viggen et al. [1], we could observe multiple Lamb wave packets being excited in the pipes. By adjusting the setup to replicate casing eccentricity, the effects of this could be observed in the measurements