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Modelling of Acoustic Wave Propagation Across Irregular Interfaces Using Immersive Boundary Conditions
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 79th EAGE Conference and Exhibition 2017, Jun 2017, Volume 2017, p.1 - 5
Abstract
A significant source of error in modelling of seismic wave propagation is caused by the response of the free-surface boundary and the interaction of the wave field with internal grid boundaries. To reduce the computational cost of simulations, the spatial discretization step is often chosen to merely satisfy a numerical dispersion criterion. For this reason, irregular interfaces present exhibit a staircase effect causing diffractions in the modeled waveforms. A finer spatial discretization of the finite-difference grid is required near the interfaces to get accurate results. To reduce the undesired additional cost caused by the finer sampling, we exploit the immersive boundary condition (IBC) method for acoustic wave propagation and its ability to dynamically link wave propagation in different domains. We enclose the irregular interface in a smaller domain that we wish to model with a finer spatial sampling, while a larger domain encloses the portion of the model discretized with a coarser spatial sampling. We show initial results for a simple layered model with two interfaces. We speculate that this method has the potential to address the long-standing issue of the implementation of the free surface in the presence of a topography.