An improved high-order rotated staggered finite-difference algorithm for simulating seismic waves in heterogeneous viscoelastic media

Abstract

By comparing the standard and staggered grid methods, a high-order rotated staggered grid algorithm has been developed for simulating seismic wave propagation in heterogeneous viscoelastic or transverse isotropic media. Numerical simulation results show that, staggered high-order staggered FD method is better than staggered pseudo-spectral method in modelling heterogeneous anisotropic or viscolastic media. Based on the algorithm, a uniform random function is used to establish random models with two kinds of components, i. e., clays and pure sandstones. These two media consist of various synthetic shale sand formations and are simulated for various clay contents. Elastic wave velocities and attenuations for various clay contents are simulated properly at the frequency around 10 kHz to 100 kHz. The numerical results show that our developed algorithms can be used for modelling composite media for studying elastic wave attenuation and velocity variation. The modelling analyses demonstrate that, the more the clay particles in the models, the more reflected backscattering produced when the wave length is around equal to the 10 times of the minimum size of the clays.