Estimation of the Subsurface Reflection Coefficient Using the Prestack Reverse-Time Depth Migration.

Abstract

The prestack reverse-time depth migration is developed to estimate the reflection coefficient of the subsurface. To examine the capability of this method, a numerical experiment is implemented and it is shown that this method gives proper reflection coefficients even for a structure with 45-degree dips. It is also applied to real data of land survey. A distribution map of the reflection coefficient can be obtained after compensating the amplitude from the 3D to 2D wavefield including consideration for the Q value. However, extracting the velocity perturbation from the estimated reflection coefficient is hard due to inaccuracy of the estimated source strength, oscillatory be- havior of the image, and lack of information about the density. The waveform inversion method is compared with the present method and it is found that the first iteration of the former method is nearly identical to the present method. Problems which are inherent in these methods are discussed.