Joint migration inversion based on reflectivity-constrained velocity estimation

Abstract

Joint Migration Inversion (JMI) automatically provides a structual image and velocity model of the subsurface by exploiting primaries and all higher order scattering. It has been shown that JMI is a robust algorithm to estimate reflectivity and velocity models, avoiding local minima. However, the estimated velocity models are relatively smooth and lack detail, as they only describe the propagation of waves. More- over, some improvement in JMI seems to be needed to generate rapid velocity variations like salt structures. In this paper we present a velocity estimation procedure including a reflectivity constraint in JMI in order to improve the accuracy of the velocity model. The residual between the estimated velocity by JMI and the approximate velocity that is derived from the estimated reflectivity is minimized through an additional constraint in the objective function. Synthetic examples are shown to demonstrate the validity of the proposed method.