Prestack depth migration in a viscoelastic medium
Theory and experiment have shown that the propagation of seismic waves in real media is in many respects different from propagation in ideal solids. In data processing, the attenuation and dispersion of the seismic wave has often been neglected. Presented here is a method for accommodating absorption and dispersion effects in prestack depth migration schemes. Extrapolation operators that compensate for absorption and dispersion have been designed. The algorithm is developed in the frequency-wavenumber domain, and is characterized by simplicity, speed, little dependence on stratum obliquity, and good stability. To test the validity of the method, a viscoelastic geology model was designed. Synthetic seismic data were generated based on the model. Viscoelastic and elastic prestack depth migration were performed on the synthetic data; the two results obtained are compared in this paper and show the influence of absorption and attenuation.