CEMENT ACOUSTIC PROPERTIES FROM ULTRASONIC SIGNAL AMPLITUDE DISPERSIONS IN CASED WELLS

摘要

Apparatus and methods for characterizing the physical state of a barrier installed in a borehole traversing a formation including locating an ultrasonic tool with a plurality of spaced receivers and a transmitter at a location in the borehole, activating the ultrasonic tool to form ultrasonic waveforms, wherein the spaced receivers record the ultrasonic waveforms, aligning the transmitter and the spaced receivers, wherein the ultrasonic waveforms comprise propagated Lamb modes, processing the ultrasonic waveforms to obtain a first amplitude dispersion plot of attenuation as a function of frequency and first phase dispersion plot of phase velocity as a function of frequency, processing attenuation dispersions to identify discontinuities, and relating the discontinuities to barrier wavespeeds.