Research On Reverse Time Migration Method In TTI Media

Since the anisotropy of media widely developed, conventional isotropic migration can not be accurate imaging in anisotropic media, so research of anisotropic migration method is very important for imaging.Reverse time migration is the most accurate imaging method in theory. Tilted transversely isotropic(TTI) media is a representative anisotropic media, and qP-wave equation can be simple and effectively simulate P wave field characteristics of anisotropic media, so the research on TTI media qP-wave equation can better play the reverse-time migration imaging technology, and also improve the imaging precision of complex formation effectively.At present, the TTI media qP wave equation to realize TTI-qP-RTM, not ignore the spatial variability of the axis of symmetry, is contained the derivative angle parameters of spatial coordinates, thus affecting the stability of equation and the reality of calculation, which is the important issues that TTI-RTM is facing.First, this paper reviews the research status of TTI media qP-wave RTM at home and abroad now, then derives different form of VTI and TTI media qP-wave equations, and introduces the basic principle of RTM, while realizes the traditional TTI-RTM. Second, we analyze several basic conditions that remain the stability of solving the qP wave equation systematically and validate them by numerical experiments. This paper mainly present and implement a stable TTI media qP-wave equation. The new equation considering the variability of symmetry axis is more stable theoretically, and it is easy to be solved because it does not contain derivatives of the model parameter in space coordinates. Therefore, it solves the stability problem of TTI-RTM. Finally, compared to the conventional equation in the model of experiment, verify the stability advantages of TTI media q P wave equations.In this study, the numerical stability conditions of qP wave equation promote the implementation of stable TTI-RTM method. The trial results demonstrate that the new equation provides effective TTI-RTM and it is necessary to discuss the RTM in TTI media.