Finite difference simulation of elastic waves propagation through 3D heterogeneous multiscale media based on locally refined grids

In order to simulate the interaction of seismic waves with microheterogeneities (like cavernous/fractured reservoirs), a finite difference technique based on locally refined in time and in space grids is used. The need to use these grids is due to essentially different scales of heterogeneities in the reference medium and in the reservoir. Parallel computations are based on Domain Decomposition of the target area into elementary subdomains in both the reference medium (a coarse grid) and the reservoir (a fine grid). Each subdomain is assigned to its specific Processor Unit which forms two groups: for the reference medium and for the reservoir. The data exchange between PU within the group is performed by non-blocking iSend/iReceive MPI commands. The data exchange between the two groups is done simultaneously with coupling a coarse and a fine grids and is controlled by a specially designated PU. The results of numerical simulation for a realistic model of fracture corridors are presented and discussed.