| CPC E21B 47/16 (2013.01) [E21B 47/005 (2020.05); E21B 47/107 (2020.05); G01N 29/041 (2013.01)] | 13 Claims |

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1. A system for evaluating well cementation, comprising:
a body configured to be lowered into a casing within a wellbore;
an emitter configured to emit an acoustic signal and coupled to the body at a pitch angle and frequency band selected to excite a mixed-mode Lamb wave comprising a symmetric extensional (Sn) mode and an asymmetric flexural (An) mode in the casing;
wherein the pitch angle is selected to primarily excite a single dominant S0 mode and a single dominant A0 mode of the Lamb wave in the casing; and
a first receiver coupled to the body at a first distance from the emitter and configured to receive a portion of the Lamb wave that has leaked from the casing at approximately the first distance and calculate a first moment (EM1) of an energy distribution between points n1 and n2 of the mixed mode (S0, A0) portion of the first waveform, given by the equation:
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