Simulation And Inversion Of Wave Equation In Viscoelastic Media

The propagation of seismic wave exists many differences in real medium and ideal medium. The viscosity of medium can dissipate energy of seismic wave and amplitude, decrease the apparent frequency. So it is hard to obtain detailed subsurface information and high resolution image directly.Absorption and attenuation of seismic wave in viscoelastic medium have been analyzed from the theory through viscoelastic wave equation. Pseudo-spectral method and finite difference method have been used to the wavefield simulation of viscoelastic medium in this paper. Different boundary conditions were introduced. The formulae of different boundary conditions in 2-D Kelvin viscoelastic medium have been derived independently. The numerical simulation compared different method and different boundary conditions. The influence of different coefficient of viscosity on wavefield absorption and attenuation has been analyzed and the conclusions about the influence of coefficient of viscosity on wave propagation have been achieved through wavefield simulation. In this base, the unite nonlinearity method of genetic algorithm and simulated annealing algorithm has been used to inverse the parameter of viscoelastic medium and obtain quality factor. Then, compensation of seismic wave absorption and attenuation in migration can obtain more correctly and accurately subsurface image.