Transmission amplitude variation with offset (TAVO)

This study presents new approximations for the transmission PP and PS coefficients from Zoeppritz equations. The approximations are presented in a form that is convenient for conventional AVO analysis. The expressions are tested using several reservoir models by comparing their performance to their corresponding Zoeppritz expressions. Results show that a one-term approximation is good at small to intermediate incidence angles while two or three terms might be required at large incidence angles approaching the critical angle. We show also that using higher number of terms does not improve the results. The presented approximations are ideal for use with VSP geometry and offer several advantages over existing reflected AVO analysis.