Modelling the wave phenomena in acoustic and elastic media with sharp variations of physical properties using the grid-characteristic method

摘要

This paper introduces a novel method of modelling acoustic and elastic wave propagation in inhomogeneous media with sharp variations of physical properties based on the recently developed grid-characteristic method which considers different types of waves generated in inhomogeneous linear-elastic media (e.g., longitudinal, transverse, Stoneley, Rayleigh, scattered PP-, SS-waves, and converted PS- and SP-waves). In the framework of this method, the problem of solving acoustic or elastic wave equations is reduced to the interpolation of the solutions, determined at earlier time, thus avoiding a direct solution of the large systems of linear equations required by the FD or FE methods. We apply the grid-characteristic method to compare wave phenomena computed using the acoustic and elastic wave equations in geological medium containing a hydrocarbon reservoir or a fracture zone. The results of this study demonstrate that the developed algorithm can be used as an effective technique for modelling wave phenomena in the models containing hydrocarbon reservoir and/or the fracture zones, which are important targets of seismic exploration.