Joint imaging of angle-dependent reflectivity and estimation of the migration velocity model using multiple scattering

摘要

Migration velocity analysis is an important method for providing an accurate velocity model for seismic imaging, which is crucial for correct focusing and localization of subsurface information. Conventionally, only primaries are considered as a source of information for both methods. The use of surface multiples in imaging is becoming more common due to the use of inversion-based approaches, which allow us to handle the crosstalk associated with multiples. However, including internal multiples in imaging and velocity estimation is not straightforward using the standard combination of reverse time migration in combination with image-domain velocity tomography. Incorporating internal multiples in imaging and velocity estimation is possible with the joint migration inversion (JMI) methodology, in which internal multiples are explicitly modeled using the estimated reflectivity via a data-domain objective function. However, to correctly match the observed data, the angle-dependent reflectivity and the migration velocity model need to be determined, which provide an over-parameterization of the inversion problem. Therefore, we have extended the JMI methodology to carry out velocity analysis via the extended image domain, in which the angle-dependent reflectivity is updated via data-domain matching. Examples of synthetic and field data with strong internal multiples demonstrate the validity of our method.