ADCIGs for forward-scattered wavefields

Jeff Shragge, Brad Artman, and Biondo Biondi

jeff@sep.stanford.edu, brad@sep.stanford.edu, biondo@sep.stanford.edu

ABSTRACT

We extend the 2-D theory of angle-domain common-image gathers (ADCIGs) to forward-scattered wavefields, and present a method for extracting reflectivity as a function of either the reflected or converted-wave receiver-side scattering angle. We use the shot-profile configuration of wave-equation migration along with planar source and receiver wavefields to generate an analytic hyper-plane surface in the intermediate offset-domain common-image gather space. Geometrical relations and partial derivatives of the hyper-plane function generate six constraint equations for the the unknown six parameters, allowing us to solve for the source- and receiver-side reflection angles and geologic dip angle. Results of numerical experiments indicate that information on wavefield focusing is present in forward-scattered ADCIGs, which suggests that this algorithm may be useful tool for improving wave-equation based tomography of transmission wavefields.