Seismic AVO Inversion with Geological Constraints

Amplitude varies with offset (AVO) inversion produces P-wave velocity, S-wave velocity and the density, which are key elastic parameters for seismic interpretation and reservoir characterization. The inversion process is based on exact Zoeppritz equations, which illustrate true relationship between the reflection coefficient and the angle of incidence. Because this inversion process is non-linear, we attempt to incorporate the geological information of layers into the inversion to constrain the results. By making use of the interpreted horizons, a geological operator can be constructed under the assumption that each geological layer is approximately homogeneous. The geological operator transforms the sample-based models into the layer-based models and hence enables the inversion results to be geologically meaningful. The first-order-derivative spatial Tikhonov regularization operator is also used to improve the lateral continuity. 2D synthetic tests have shown that with the proposed geological layer constraints and spatial regularization operator, it is able to obtain geologically reliable results with high lateral continuity.