Sub-salt imaging of a 2-D elastic synthetic model, using prestack, split-step, wave equation migration

Douglas Gratwick

doug@sep.stanford.edu

ABSTRACT

This paper explores methods to image complex structures under a salt body, using a 2-D elastic synthetic model. The modeling algorithm handles complex features such as energy from multiple reflections and mode conversion. I show that a complex wave equation depth migration algorithm is needed to position the salt boundaries and reflectors from sediments below the salt properly. Also, using simple ray-tracing diagrams, I show that energy from converted waves is useful in imaging steeply dipping reflectors below the salt. Though these techniques improve overall image quality, parts of the image under the salt are still left unresolved, and I outline possible techniques for imaging these reflectors.