The AVO modelling volume

Abstract

An AVO modelling scheme is proposed in which we create a 3D volume of modelled CDP gathers by varying two physical parameters, one in the in-line direction, and one in the cross-line direction. This 3D volume is then processed using conventional AVO analysis techniques, and the results are interpreted using time or structure slices. Two examples are presented. The first involves P-wave velocity change in one direction versus S-wave velocity change in the other. In the second, we change porosity in one direction against water saturation in the other, using the Biot-Gassmann equations to perform the modelling. In the first example, an excellent fit is obtained between actual and expected results. In the second example, the fit is encouraging, but far from perfect. This study has therefore motivated future research into the use of multi-attribute statistical methods on this problem.