The first arrival imaging condition,maximum amplitude imaging condition and cross-correlation imaging condition are three main imaging conditions used in prestack reverse-time migration.The arrival time of the incident waves in the grid were used by both the first arrival imaging condition and the maximum amplitude imaging condition.The first arrival imaging condition considers the first arrival time obtained by ray tracing or eikonal equation as imaging time,and is suitable for simple medium.However,the maximum amplitude imaging condition considers the time at which maximum amplitude appeared as imaging time,and has improved imaging quality.The cross-correlation imaging condition uses the cross-correlation between incident waves and reflected waves.However this condition needs to simulate field recording of wave propagation before migration.Imaging condition computation and data storage are huge.The advantage of cross-correlation imaging condition is that it can image repeatedly.Marmousi model examples demonstrates that the cross-correlation imaging condition has good multiple imaging and better denoising performance than the first arrival time imaging condition and the maximum amplitude imaging condition.
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