Updating velocity using hyperbolic gamma, tomography and FWI - A comprehensive in-house model building workflow

Summary We propose a comprehensive workflow for velocity model building. Our strategy avoids a relatively lengthy process of stacking velocity analysis and can proceed all the way to producing a high-resolution interpretable velocity model. The workflow includes three major parts: 1) computing hyperbolic gamma from depth-migrated common image gathers and adjusting the velocity model accordingly, an efficient step that can significantly reduce the nonlinearity in the inversion problem, 2) employing ray-based tomography, an industry-workhorse which is routinely used to construct a low-frequency velocity field for depth imaging, and 3) using FWI, the state-of-the-art technology for building a high-resolution velocity model for both imaging and interpretation. The workflow has been applied to both synthetic and field data examples and the results demonstrate the successes of applying our comprehensive in-house model-building capability.