Inverse AVO problem for a stack of layers

Abstract

The problem of estimating thin layered model parameters by amplitude variation with offset (AVO) inversion has been studied. The motivation was resolving of the thin layers in inverted prestack seismic data as it contains more information on elastic properties of the subsurface than poststack seismic data.In this paper, an algorithm for solving the prestack inverse AVO problem in the case of multilayered media is derived. This algorithm is based on iterative corrections to the parameters of the initial model which tend to minimise the misfits between observed and synthetic seismograms. The synthetic seismograms are calculated using the reflection–transmission (RT)-matrices method, assuming a plane-wave with respect to the source position.A regularised Gauss-type algorithm for the inversion of prestack seismic data has been used. A differential seismogram computation algorithm to characterise the sensitivity of the seismic signal to the variations of a model parameter was used. The derived solution of the inverse problem is constructed in the time domain. This gives a slight advantage because it allows for visual control of the solution process. One can monitor the amplitude reduction of the data residual (difference between observed and synthetic seismograms) during the iteration process. Numerical examples show the accuracy and efficiency of the method.