The earth filtering is inevitably in seismic wave propagation and the parameters to represent earth filter intensity is the absorption coefficient and the Q value. Using zero-offset vsp's down-going direct wave to estimated Q value is considered the most reliable way to extract stratigraphic quality factor Q value. We used Ken 71 well zero-offset VSP down-going direct wave with the centroid frequency shift method to estimate layer Q value. First, by processing the zero-offset VSP data, we separated down-going-direct wave and up-going wave. Then, we analysis and calculated the layer-velocity and layer Q value using down-going wave. At last, we made the bridge comparison chart by the up-going-wave processed. The bridge comparison chart compared with the layer-velocity and layer-Q value, results show that the corresponding relations are very good.

A key issue in the wave equation simulation of seismic records is the boundary conditions. Due to computer memory and computation and other restrictions, can only be solved on a limited area, which will cause the introduction of an artificial reflector. So as to simulation of seismic wave propagation in an infinite medium, the boundary conditions must be constructed so that the interface of the reflection as little as possible. In 2.5D VTI media feature analysis absorbing boundary of higher order velocity-stress staggered-grid finite difference method are established. The mixed boundary of the feature analysis absorbing boundary plus damping attenuation condition is used in 2.5 D VTI numerical simulations, simulation results show that this method is an efficient absorption and attenuation boundary conditions.