Joint Reverse Time Migration of Primaries and Internal Multiples Based on Imaging Constraint

The presence of internal multiples significantly impacts seismic data imaging. Due to the subtle differences in velocity and energy between primaries and internal multiples, the task of eliminating internal multiples poses a significant challenge, often leading to inaccuracies or high costs using current methods. Considering that the internal multiples are also real reflections from interfaces containing valuable structural information, reverse time migration (RTM) can be used to handle their imaging but with artifacts introduced. Therefore, to avoid the high costs associated with internal multiple suppression and to address the impact of internal multiples on imaging, our study focuses on the joint imaging of primaries and multiples using RTM, aiming to mitigate the influence of internal multiples artifacts during the imaging process. First, the generation of the artifacts in joint imaging of primaries and internal multiples is analyzed. Then, an imaging constraint strategy is proposed for the images of separated upgoing and downgoing wavefields based on similarity analysis to address the image artifacts, according to the different behavior of the separated images. Finally, the feasibility and effectiveness of the proposed method are verified by numerical examples. The proposed method can realize the elimination of image artifacts in the image domain instead of suppression of internal multiples in the prestack data domain, thereby reducing calculation costs. In addition, the migration of internal multiples may offer potential advantages in imaging complex cases.