Including internal multiples from the estimated image in least-squares reverse-time migration

Abstract

Least-squares reverse-time migration (LSRTM) nowadays is a standard inversion-based seismic imaging method. One of the advantages of this approach is a high accuracy of the forward propagator, with which it is easy to handle large variations in the medium and to image vertical structures via diving waves. LSRTM estimates perturbations of the background model under a linear assumption (the Born approximation), therefore only single scattering generated in the subsurface is addressed and internal multiples are considered as noise, which results in image artifacts (crosstalk). In this paper we investigate an option to include internal multiple scattering in the forward model of LSRTM, while still using a smooth background model. This is achieved by introducing two-way scattering sources from the concept of Full Wavefield Migration, which will generate the higher-order scattering due to the imaged reflection structures. The methodology is demonstrated on synthetic and field data, showing its capabilities in properly handling internal multiples.