Seismic Lithology Sections

Seismic amplitudes are estimated by computing coefficients in a reflectivity polynomial as a function of offset. By considering a small-contrast approximation of the PP reflection coefficient, the coefficients in the reflectivity polynomial can be related directly to the relative changes in elastic parameters. This provides seismic lithology sections for the relative change in P-wave acoustic impedance, P-wave velocity, density and plane-wave modulus. The change in bulk modulus and shear modulus normalized with the plane-wave modulus can also be estimated. By using an average S-wave velocity several other lithology sections can be computed. These include the relative change in the P-wave to S-wave velocity ratio and a fluid factor section. Various lithology sections have been computed for a shallow seismic anomaly in the Southern Barents Sea.