VPS高阶有限差分正演模型

采用有限差分法求解声波方程．较好地应用吸收边界、自由边界及震源，成功地模拟了地下半无限非均匀介质中声波传播的物理过程；获得了能清楚分辨反射波、多次波、绕射波等各种波型的声波ＶＰＳ剖面．该方法可用于计算构造任意复杂的地震模型．用精度较高的四阶差分格式代替传统的二阶差分格式求解声波方程，得到高精度的差分解．各种构造模型的计算实例表明，此方法已达到实用水平．

High Order Finite Forward Modeling for VSP of Acoustic Wave Equation

The finite difference method was used to solve the acoustic waves equation. By properly using the absorbing boundary, free boundary and the seismic source,the physical procedure of acoustic waves propagating in semi-infinite inhomogeneous midia was simulated. Various kinds of acoustic ways such as reflection, multiplie, diffracted waves can be clearly seen in the vsp profile obtained by the method.The method provided in this paper can be used to compute the seismic models which are as complicated as they could be. Instead of using common second-order finite difference algorithm,the paper adopted the fourth-order difference algorithm tosolve the acoustic wave equation and resulted in difference solution of high accuracy. The computing examples of different kinds of structure models show that the method in this paper can be put into practical use.