Suppressing Migration Artifacts Using Angle-Domain Least-Squares Migration

Migration artifacts are usually presented in the migrated image or angle-domain common-image gathers (ADCIGs) recovered from the seismic migration operators. When these migration artifacts are not properly suppressed, they may significantly degrade the accuracy of subsequent structure interpretation, amplitude-versus-angle inversion, and reservoir characterization. In this article, we apply an angle-domain least-squares migration (ADLSM) method to suppress these migration artifacts presented in the migrated ADCIGs. There are two key points in this proposed method. The first point is that we explicitly compute the angle-domain Hessian matrix and invert it by the regularized linear inversion technique. Thanks to the introduction of diagonally band Hessian matrix, the migration artifacts at the far-field can be effectively suppressed. The second point is that we have incorporated the smoothness prior of the reflection-angle-dependent reflectivity image along the reflection angle direction into the linear inversion. We determine the validity of the proposed ADLSM method within the Kirchhoff migration. Through the SEG/EAGE Salt model and field data, we demonstrate that the proposed ADLSM method can effectively and efficiently suppress these migration artifacts in the migrated ADCIGs recovered from the Kirchhoff migration. In addition, even when the migration velocity is less than the true velocity model, this method remains valid.