Multiangle, multiscale inversion of migrated seismic data

Abstract

The relation between the angle‐dependent reflectivity of an interface in a target zone and the amplitude‐variation‐with‐offset (AVO) effects observed in the seismic data at the earth’s surface is complicated by many factors, as was pointed out in Ostrander’s classic paper (Geophysics, 1984). Some factors are “reflection related” (such as thin‐bed tuning, reflector curvature), others “propagation related” (such as geometrical spreading, transmission and/or anelastic losses), or “acquisition related” (such as source/receiver directivity, geophone coupling). Amplitude‐versus‐angle (AVA) inversion in a target zone can be carried out successfully only when these effects are taken into account, either by forward modeling or by stepwise processing prior to AVA inversion. In the Delphi research program, we opt for the latter. For example, by decomposing multicomponent ocean‐bottom measurements into P- and S-wave responses, the effects of receiver directivity are implicitly suppressed. Furthermore, the geometrical...