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KAUST-IAMCS Workshop on Modeling and Simulation of Wave Propagation and Applications

Richard Gibson, Texas A&M University
Multiscale Finite Element Modeling of Acoustic Wave Propagation

Abstract

Numerical simulation of acoustic wave propagation provides important insights for interpretation and inversion of seismic data acquired in areas with complex, heterogeneous hydrocarbon reservoirs. However, important problems arise in applying numerical methods to models including fine scale heterogeneities such as fractures in common finite difference algorithms that rely on uniform grids, since the complex features are difficult to represent accurately on grids with spacing of 10 to 20 m. Effective medium theories are often used to approximate material properties in such cases, but it is likely that more complex media will not be accurately calculated by such solutions. This provides strong motivation for the development of multiscale finite element algorithms for simulating acoustic wave propagation in complex media, as such algorithms offer the potential of allowing more reliable results by combining fine- and coarse-scale grids. The relevant equations are solved on a coarse grid, allowing application to models of large earth structures, but a global coupling mechanism relates information between the two grids. Time-stepping also takes place on the coarse grid, facilitating savings in computation time. The presentation will emphasize examples of application of this method to models similar to those of interest for hydrocarbon exploration, including migration imaging of strongly heterogeneous media using reflected waves. The results will show how the multiscale method can accelerate simulations of seismic surveys for validating earth models and for applications such as inversion of seismic waveforms.