Patent ID: 7120541

Claim:
A method for determining a characteristic of a formation traversed by a borehole, comprising the steps of: a) obtaining signals from a plurality of sonic detectors, which signals include dispersive waveform information; b) Fourier transforming at least a portion of said signals to obtain Fourier transformed signals; c) backpropagating said Fourier transformed signals utilizing a dispersion curve defined by a plurality of parameters to obtain a set of backpropagated signals, said plurality of parameters including at least one of (i) a slowness at an indication of first frequency and a slowness at an indication of second frequency, (ii) an indication of a kick-in frequency, and (iii) and an indication of a flexion frequency; d) modifying at least two of said plurality of parameters according to a search algorithm, and repeating said backpropagating step a plurality of times with modified parameters; and e) using sets of backpropagated signals, identifying a best-fit dispersion curve for at least one depth of the formation.