Multiparameter Acoustic Inversion for Variable-Tilt Transversely Isotropic Media with Generalized Radon Transform

The pseudoacoustic approximations are commonly used for migration and inversion in transversely isotropic (TI) media, as they accurately characterize the P-wave propagation and are simpler than their elastic counterparts, resulting in computational savings. This article is devoted to presenting an approach for generalized Radon transform (GRT) migration and inversion in acoustic TI media with a tilted symmetry axis (TTI). In parameterizing an acoustic TTI medium with the P-wave normal move-out (NMO) velocity v(n), Thomsen's parameter d, and anelliptic parameter 4, a concise single-scattering integral for NMO pressure is obtained by perturbing the TTI medium from a background nonelliptically anisotropic medium. It results in explicitly representing the perturbation scattering patterns of each parameter (v(n), d, and 4), helping us understand the scattering angular influence of the perturbed parameters. The application of GRT on this scattering integral allows a direct construction of the acoustic TTI inversion operator. Numerical examples verify the effectiveness of the proposed acoustic TTI GRT inversion method and show its considerably good performance in the presence of steeply dipping anisotropic layering.