Using higher-order scattering in seismic imaging

Abstract

For seismic exploration, acoustic sources and receivers are positioned at the earth's surface in order to measure the reflection response from the subsurface inhomogeneities. However, in most current imaging algorithms, only the primary reflections are being taken into account and multiple reflections are being discarded as noise. In the recently proposed method of full wavefield imaging, the higher-order scattering is taken into account in the imaging process where they contribute to extend the illumination area and no longer produce spurious imaging artifacts. This method involves an inversion process, where a recursive modeling method is used to predict the measured reflection response—including all its higher-order scattering effects—based on estimated reflectivity values and background velocity model. Because the background velocity cannot be assumed to be homogeneous in the earth, background velocity model estimation is a crucial component of the imaging process. It appears that automatic estimation of velocity models can be accomplished within the concept of full wavefield migration, in which higher-order scattering events can also be fully accommodated. Finally, the results of full wavefield imaging can be combined with localized, target-oriented full waveform inversion in order to get the final details, being the elastic properties, at the target zone.