Offset Weighting for Multiple Suppression in AVO Analysis

Contamination of primary reflections by remnant multiple reflections continues to<br>degrade the results of rock property estimation from Amplitude Versus Offset (A VO)<br>analysis of seismic data. Conventional stacked seismic sections benefit from the<br>application of near and far trace tapering prior to stacking, but this would not seem<br>applicable in AVO analysis. Presented here is a means whereby offset weighting<br>schemes can be incorporated into A VO analyses, resulting in improved multiple<br>suppression. The weighting is inserted into the Aki and Richards approximation to the<br>Zoeppritz equations, and thus can be used with any method which attempts to<br>minimise the error between the observed and predicted seismic amplitudes. The<br>incorporation of this weighting into the GEOSTACK method of Smith and Gidlow is<br>demonstrated, together with a real data example showing the multiple suppression<br>achieved by this approach. The combination of a suitable multiple suppressing<br>weighting scheme and a least squares minimisation approach produces a more robust<br>method of AVO processing in the presence of multiples or any other noise.