Reverse-time migration using pseudo-spectral method for tilted TI media
Wang Weiguo1, Xiong Shuijin1, Xu Huaning1, Qian Rongyi2
1. Guangzhou Marine Geological Survey,Guangzhou,Guangdong 510760,China;
2. School of Geophysics and Information Technology,China University of Geosciences(Beijing),Beijing 100083,China
Abstract：Based on Thomsen's accurate phase velocity formula and weak anisotropic assumption,an approximate phase velocity formula in TTI media is derived in this paper by expanding the phase velocity formula in VTI media.Using this approximate phase velocity formula to wave equation,P-wave equation is derived.Pseudo-spectral method is employed to forward simulating and reverse-time migration(RTM).Comparing isotropic pre-stack depth migration in F-X domain with RTM,the following indications are obtained: ①For anisotropic media,migration results by isotropic algorithms may have visible error,and this will cause imaging problems.②With the consideration of cost,efficiency and accuracy,it is a good idea to use pseudo-spectral method which solved the space derivative problem with FFT instead of RTM.③The approximate wave equation can be well used in TTI media on weak anisotropic assumption.
