when induced in casing 8 surrounded by light weight cement therefore lamb waves are well suited for use in the analysis of cement bonds comprised of regular or light weight cement furthermore propagating lamb waves into the bond can also help detect defects therein such as the presence of a microannulus 20 or water 22 as well as a poor bond 24 as noted above lamb waves have the capability to couple into light weight cements but will not couple into bond defects as such the presence of any of these defects disposed between a transmitting and a receiving transducer can be discovered by monitoring the resulting attenuation of the lamb wave propagating across the defect it is well within the capabilities of those skilled in the art to study monitored attenuation results in order to detect the presence of bond defects it should be pointed out that the transducer in question can comprise two or more transducers 16 a 16 b as shown in fig3 and 4 but could also comprise a single transducer capable of transmitting and receiving an acoustic signal analysis of a lamb wave 39 s attenuation induced within casing 8 can reveal not only cement characteristics but also.