Abstract
Due to the finite beam radiation and reception of the cased well Lamb-wave measurement and the plane-wave propagation approximation, the influence of wave spreading on wave amplitude attenuation is often ignored. To investigate the problem, the logging response characteristics of the ultrasonic pitch-catch measurement system in cased wells are analyzed using numerical modeling and experimental measurement. The snapshots of displacement wave field in the casing for different offsets are compared, from which the apparent radiation spreading of the wave field is observed. In the measurement, the receivers have reception directivity and the flexural Lamb wave propagation is in the arcuate casing. As a result, the attenuation measured from the waveform amplitude of the near and far receivers is affected by these effects; the closer the ultrasonic pitch-catch system gets to the inner wall of the casing, the greater the measured attenuation value is, as is caused by the Lamb wave spreading from the arcuate casing. The results of this study demonstrate that a correction for this wave radiation or spreading effect is needed for using the attenuation measurement for cementing quality evaluation.
How to Cite:
Chen, X. ., Tang, X. ., Tao, A. ., Li, J. . & Cheng , L. ., (2019) “Modeling casedhole lamb-wave characteristics for an oriented transmitter and receiver system”, Review of Progress in Quantitative Nondestructive Evaluation .
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