Amplitude Corrections For Avo In Anisotropic Media

In order to preserve the true relative amplitude in the reflection coefficient response of an interface, the AVO processing<br>sequence must consider the anisotropic effects of the subsurface. The influence of the anisotropy on the reflected<br>seismic amplitudes depends on three distinct factors: the source directivity, the geometrical spreading and the reflection<br>coefficients. In general anisotropic media all these factors have angular dependence, such that they are important and<br>must be considered when performing AVO analysis.<br>In this paper we investigate the influence of these three quantities on the estimated reflection coefficient response<br>(reflection coefficient versus angle curve), which is obtained by making specific amplitude corrections on the registered<br>seismic amplitudes. We evaluate and compare both the true anisotropic and the usual isotropic corrections for a plane<br>interface model consisting of an anisotropic layer over an isotropic one. The vertical transversely isotropic (VTI) and<br>orthorombic symmetries are considered in this work, by their importance in reflection seismic. The results shows that the<br>AVO response is strongly anisotropic dependent and that the AVO interpretation can clearly be distorted if anisotropy is<br>not considered.