  This article presents a set of acoustic measurements conducted on the Statoil
funded Behind Casing Logging Set-Up, designed by SINTEF Petroleum Research to
resemble an oil well casing. A set of simple simulations using COMSOL
Multiphysics were also conducted and the results compared with the
measurements. The experiments consists of measuring the pressure wave radiated
of a set of Lamb waves propagating in a 3 mm thick steel plate, using the so
called pitch-catch method. The Lamb waves were excited by a broadband
piezoelectric immersion transducer with center frequency of 1 MHz. Through
measurements and analysis the group velocity of the fastest mode in the plate
was found to be 3138.5 m/s. Measuring the wave radiated into the water in a
grid consisting of 8x33 measuring points, the spreading of the plate wave
normal to the direction of propagation was investigated. Comparing the point
where the amplitude had decreased 50 % relative to the amplitude measured at
the axis pointing straight forward from the transducer shows that the wave
spread out 3.2 mm after propagating 140 mm in the plate.
