Least-squares Reverse Time Migration of Multiples in Visco-acoustic Media

Multiples are also real reflections from the subsurface with longer propagation path and smaller reflection angle than primaries. Consequently, they can provide wider illumination, higher fold, and better vertical resolution of the subsurface. So instead of suppression, multiples have been used to improve seismic imaging in recent years. However, the much longer propagating path makes the energy of multiples attenuates seriously especially in the viscosity media. Besides, the artifacts caused by crosscorrelation of unrelated events are introduced in the image. These problems severely decrease the quality of multiple image. Therefore, we present to do the imaging by the LSRTM of multiples in the visco-acoustic media. The amplitude can be compensated and the artifacts can be suppressed gradually during the iterative inversion. Then, a perfect image with more information, more balanced amplitude and higher resolution can be acquired. Numerical examples effectively demonstrate the advantages of this method.