Patent ID: 6941231

Claim:
A method for estimating the time varying mechanical properties of a cement comprising: (i) propagating acoustic waves through a sample ( 3 ) of the cement; (ii) measuring signals corresponding to the acoustic waves after propagated through the sample ( 3 ); (iii) comparing attributes from the measured signals with attributes from corresponding signals provided by a calculating model, the calculating model accounting for at least initially estimated acoustic properties of the cement; (iv) using the differences between the measured and calculated signals to update the initially estimated acoustic properties of the cement in the calculating model; (v) processing (N) iterations of comparison and updating until a predetermined calculating stop; and (vi) calculating the time varying mechanical properties of the cement from the final iterated acoustic properties; wherein the step of propagating acoustic waves through the sample comprises propagating acoustic waves at an incidence angle Θ to the surface of the sample of greater than zero so as to propagate shear waves through the sample.