True Amplitude Reverse Time Migration - From Reflectivity to Velocity and Impedance Perturbations

Conventional prestack depth imaging methods aim at producing a structural image, which delineates the interfaces of the geological variations or the reflectivity of the earth. With the help of broadband acquisition and processing techniques, the bandwidth gap between depth imaging and seismic inversion is reducing. Here, we propose a theory to show how impedance and velocity perturbations can be estimated from the angle domain common image gathers produced by a true amplitude reverse time migration. The near angle stacked image provides the impedance perturbation estimate, while the far angle images can be used to estimate the velocity perturbation. Together with the ghost compensation technique, the method described here can be a useful tool of seismic inversion for marine exploration. Both synthetic and real data examples have demonstrated that the method is reliable and provides additional information for interpreting geological structures and rock properties.