ELASTIC IMPEDENCE: MODELLING AND INVERSION

Abstract

Elastic impedance is a generalization of acoustic impedance for nonnormal angles of incidence; whereas Acoustic impedance is valid for normal incidence. Elastic impedance provides a absolute and consistent framework to calibrate and invert non-zero offset seismic data same as Acoustic impedance does for zero offset data. Elastic impedance, which is an approximation derived from a linearization of the zeoppritz equations, is accurate enough for widespread application. Elastic impedance depends on incidence angle. For non- .4 normal incidence elastic impedance can be expressed in terms of Elastic impedance. Elastic impedance for p-wave also depends upon S-wave velocity. Its been suggested that elastic impedance inversion of data gives better results. Elastic impedance gives a easy mechanism to produce synthetic seismogram for variable incidence angle. In the present work presented synthetic seismogram have been produced and inverted using aki-richards approximation and the elastic impedance concept for a number of earth models. It has been found that there is no essential difference between the aki-richard inversion and inversion based on elastic impedance when results are compared in terms of AVO attributes A and B.