Can we quantitatively image complex structures with rays?
Résumé
Ray‐based prestack depth migration fails to image quantitatively complex structures when a single arrival—for example, the first or the strongest one—is taken into account. In this paper, we investigate whether accounting for multiple arrivals in ray‐based preserved amplitude prestack depth migration allows one to improve quantitative imaging of complex media. The asymptotic ray‐Born migration/inversion, originally designed to process one single arrival, is extended to the case of multiple arrivals by accounting for the cross‐contributions of all the source and receiver raypaths. Multiple arrivals in the folded ray fields are computed by a dynamic ray tracing based on a wavefront construction technique. With an application to the complex Marmousi model, we demonstrate that ray‐Born inversion can provide a reliable quantitative estimation of the relative impedance perturbation even in the complex deep part of the model, for which the amplitudes were underestimated drastically when only a single arrival was used, either the first or the strongest one. This 2-D case study shows that complex structures can be imaged quantitatively with rays. Future studies will require the optimizing of the implementation of ray‐Born migration/inversion with multiple arrivals before considering 3-D applications.