Local angle-domain Gaussian beam prestack depth migration in a TI medium

Angle-domain prestack depth migration based on anisotropic ray theory can provide strong support to the structural imaging in the depth domain and angle-gather-based seismic tomography. The Gaussian beam prestack depth migration has shown its great advantages in accuracy of complex structural imaging, computational efficiency and flexibility. In this paper, we focus on implementing Gaussian beam perstack depth migration in the framework of local angle domain imaging. In order to improve the efficiency and practicability of proposed algorithm, we discuss a kind of phase velocity based kinematic and dynamic ray tracing systems, which is evolved from the classic ray tracing equation of anisotropic media. And we propose a more economical program for constructing anisotropic Gaussian beams. Combined with the principle of seismic local angle domain imaging, we discuss an angle parameter calculation method which is suitable for Gaussian beam migration. Numerical tests on the standard theoretical anisotropic models show that compared with local angle domain Kirchhoff migration, our approach has a higher imaging precision and better anti-noise ability. It also can be used as an imaging tool for complex geological structures and efficient migration engine for anisotropic migration velocity analysis and model construction.