Acoustic Finite-difference Prestack Reverse Time Migration with Adaptive Variable Length Spatial Operators

Prestack reverse time migration (RTM) is a very useful tool for seismic imaging, and one of its key problems is wavefield forward and backward extrapolation. The essence of wavefield extrapolation is numerically solving wave equation. To improve the accuracy and efficiency, we adopt finite-difference method with adaptive variable length spatial operators to solve acoustic wave equation and thus to extrapolate wavefield forward and backward. In addition, we use the normalized cross-correlation imaging condition and Laplace operator for removing the low frequency noises. Synthetic data tests demonstrate that this RTM scheme improves imaging effect and computational efficiency greatly comparing with conventional finite-difference RTM.