3D synthesized areal shot-record residual migration velocity analysis

Abstract

Velocity analysis is always a critical step during seismic processing due to its influence on the final quality of the data. Over the last few decades, residual migration velocity analysis (RMVA) as a popular tool to estimate a velocity–depth model has been an area of active research. Previous works on the RMVA have been computationally intensive to be applied in 3D cases. In this paper, we propose a 3D synthesized areal shot-record RMVA method with controlled illumination. In the scheme, the interval velocities are updated using the residual analysis in the plane wave domain only with the layer-stripping residual correction rather than the layer-stripping prestack depth migration (PSDM). The synthesized areal shot-record migration is performed in the plane wave domain. This is consistent with the condition of the velocity correction formulae. The common image gather (CIG) sections can be extracted directly from the migrated data. To avoid the propagation distortion of the plane wave source wavefield through an inhomogeneous subsurface, the controlled illumination technique is employed. Results on both synthetic data and field data demonstrate that the method is practical and efficient.