Perfectly Matched Layer Absorbing Boundary Condition of Finite Element Prestack Reverse Time Migration in Rugged Topography

Boundary reflection is an important problem of numerical simulation in limited domain. Perfectly matched layer (PML) absorbing boundary condition (ABC) is one of the best choices to eliminate boundary reflection. Generally, forward modeling needn’t consider PML ABC in free surface, but in prestack reverse time migration, false events will be existed due to the free surface reflection. The goal of this article is to derive the PML ABC formulas of second-order finite element acoustic wave equation based on rugged topography in displacement form and apply it in finite element numerical simulation in rugged topography. Several numerical modeling results are compared. The numerical results show that PML ABC based on rugged topography obtains a much better boundary absorption effect than that of CE ABC, which shows the advantages of this method. So it will eliminate the fault events result from the free surface reflection in prestack reverse time migration based on rugged topography.