Study On Forward Modeling In Viscous Media And Anisotropic Media Based On Dual-variable Grid

The conventional FD method requires that the domain be discretized into an evenly spaced grid,In order to study seismic wave propagating rule in complex medium,we must use sufficiently fine grid,but this results in an increase of computational memory and time.To overcome these problems,people propose a discontinuous grid FD seismic modeling,that the computation in fine grid is used in local complex medium area,the computation in coarse grid is carried out in rest area.We use a staggered grid FD method using localized discontinuous grids in combination with locally variable timesteps for modeling.The efficiency and accuracy of the discontinuous grid were explained by comparison with the conventional constant grid and timestep FD method.The results show that the proposed discontinuous grid FD attains huge savings in terms of both the computational memory and time without a remarkable loss of accuracy.The underground media has significant effect on wave field,such as attenuation and dispersion.Therefore,the study of seismic wave based on viscous media has important theoretical and practical significance.The generalized standard linear solid is an effective approximation to the earth media.In this paper,we propose a staggered FD method using the dual-variable grid size in time and space based on SLS wave equation for modeling of wave propagation in viscous media.Compared with the conventional finite difference method,some numerical tests demonstrate the accuracy and efficiency of the new method.The research on the propagation of seismic wave in viscous media can lay a solid foundation for migration and inversion.The property of anisotropy is widely existed in the actual formation.It has significant influence on the kinematics and dynamics of propagating waves.If anisotropic effects are neglected,it will lead to errors in migration and inversion.It is very necessary to take the anisotropy of the underground media into consideration.The research on the propagation of seismic wave in anisotropic media can lay a solid foundation for migration and inversion.In this paper,we propose a staggered FD method using the dual-variable grid size in time and space for modeling of qP-wave propagation.Compared with the conventional finite difference method,some numerical tests demonstrate the accuracy and efficiency of the new method.