A Method to Avoid the Snapshots Wavefields Storage in Reverse Time Migration

Prestack reverse time migration based on two-way wave equation has been proved the most accurate migration methods for seismic imaging. But it is significantly constrained by modern computers’ memory size and hard disk access speed, especially used in 3D imaging. The random boundary condition can be used to avoid the disk need for saving the wavefield during the forward wave propagation. However, the random wavefield reflected from the boundary can lead the unwanted artifacts in the reverse time migration images. In this paper, we proposed an attenuation random boundary condition, which is mixed by attenuated boundary condition and random boundary condition. Compared to the images using the random boundary condition, the images using the attenuation random boundary condition can eliminate the unwanted artefacts, and improve the computational efficiency greatly.