Image domain least-squares migration based on ray-based point spread function

Least-squares migration is able to eliminate the adverse effects of irregular seismic acquisition, band-limited source wavelet and other factors on seismic migration, and improve imaging resolution and illumination. However, the huge computational cost significantly hinders the application of this method. In this paper, we present a fast point spread function calculation method based on ray-based Green's function and first -order traveltime approximation, which not only can reduce the computational cost but also can adapt arbitrarily spatial sampling to ensure interpolation accuracy. Then, we develop an imaging domain least-squares migration method to produce subsurface reflectivity with higher resolution and amplitude fidelity. The synthetic and the real data tests verify the correctness and effectiveness of the proposed method.