CRS Shot Gather Reconstruction and Regularization for Improved Prestack Imaging

The structural resolution of complex subsurface geology generally requires advanced prestack depth migration based on wave-equation algorithms. The full benefit of these costly algorithms, however, may be missed in case of irregular spatial data sampling, and high noise contamination. A new data regularisation strategy is proposed including both, a careful regularisation of the shot data, and an enhancement of the signal-to-noise ratio, making use of the Common-Reflection-Surface (CRS) method. In contrast to previous CRS regularization strategies in the CDP-offset domain, the new strategy defines the target traces of the CRS prestack data mapping within so-called CRS shot gathers. This data mapping may preserve the existing shot geometry supplying CRS-based noise suppression only, or may build CRS shot gathers at new geometries with a desired regularity. The effectiveness of the approach is demonstrated at a 3D seismic dataset. In a first CRS processing using all prestack data, the existing shot records are reconstructed as CRS shot gathers with preserved geometry. In a second CRS processing, some shot data is omitted in the input, and then rebuilt as CRS shot gathers. Both applications show a strong increase of the signal-to-noise ratio with a good preservation, or reconstruction, respectively, of the original events.