Angle-Domain Least-Squares Reverse Time Migration In 2D Tilted Transverse Isotropic Media

Extending least-squares reverse time migration (LSRTM) to tilted transverse isotropic (TTI) media (TTI-LSRTM) improves imaging accuracy. However, TTI-LSRTM necessitates multiple migration parameters, including velocity, density, anisotropy parameters, and symmetry axis tilt angle θ _t of the stratum. Current multi-parameter inversion methods face challenges due to parameter coupling and high nonlinearity, making it difficult to provide accurate migration parameters for TTI-LSRTM. To address these limitations, we propose an angle-domain LSRTM in TTI media (TTI-ALSRTM), which extends Born modeling and gradient calculation from the space domain to the space-angle domain. Our method ensures robust data matching and rapid convergence even with inaccurate migration parameters. Additionally, it extends RTM-based angle-domain common image gathers (ADCIGs) from isotropic media to LSRTM-based ADCIGs in TTI media, enhancing their reliability. Numerical experiments on two-layer and Marmousi models, as well as field offshore streamer data demonstrate its efficacy and practicality.