Seismic Reverse Time Migration With Random Boundary and Frequency Modulation

In seismic reverse time migration (RTM), the random boundary condition (RBC) method can be used to reduce the amount of storage required to store the source or receiver wavefield. However, the RBC method generates low-frequency coherent noise in the wavefield, which is a remnant of the artificial reflections at the random boundaries. To solve this problem, we have proposed a frequency modulation method for the RBC-based RTM, in which the dominant frequency of both the source and receiver wavefields is shifted upward. This method not only mitigates the low-frequency coherent noise of the RBC method but also improves the resolution of the RTM image.