Depth imaging using CRS shot gathers in reverse time migration

Depth migration based on wave-equation algorithms have been established as standard tools in the processing of reflection seismic data. Reverse time migration (RTM) provides depth images of high accuracy but may be hampered by low data quality, and noise contamination. In such cases the combination of RTM with prestack data preconditioning by the Common-Reflection-Surface (CRS) technique can improve the imaging result. While previous CRS strategies for prestack data mapping regularized CMP and offset coverage for an improved Kirchhoff migration, a new CRS strategy provides so-called CRS shot gathers that preserve the original shot geometry while providing a strong noise suppression. These CRS shot gathers are well suited as input of shot based depth migration algorithms like one-way wave equation and reverse time migration (RTM). These state-of-the-art migration techniques benefit from the strong signal-to-noise ratio of CRS shot gathers. The reverse time migrated shot gathers in offset and angle domain offer new possibilities for velocity analysis in complex geologic structures.