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Frequency-domain acoustic wave modeling using a hybrid direct-iterative solver based on a parallel domain decomposition method: a tool for 3D Full Waveform Inversion?
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 70th EAGE Conference and Exhibition - Workshops and Fieldtrips, Jun 2008, cp-41-00079
- ISBN: 978-94-6282-104-0
Abstract
Frequency-domain full-waveform tomography has been extensively developed during last decade to build<br>high-resolution velocity models (Pratt, 2004). One advantage of the frequency domain is that inversion<br>of few frequencies are enough to build velocity models from wide-aperture acquisitions. Multi-source<br>frequency-domain wave modeling requires resolution of a large sparse system of linear equations with<br>multiple right-hand side (RHS). In 2D, the method of choice for solving this system relies on direct solver<br>because multi-RHS solutions can be efficiently computed once the matrix was LU factorized. In 3D or<br>for very large 2D problems, the memory complexity of direct solvers precludes applications involving<br>hundred millions of unknowns. To overcome this limitation, we investigate a domain decomposition<br>method based on a Schur complement approach for 2D/3D frequency-domain acoustic wave modeling.<br>The method relies on a hybrid direct-iterative solver. Direct solver is applied to sparse matrices assembled<br>on each sub-domain, hence, mitigating the memory complexity of the overall simulation. Iterative solver<br>based on a preconditioned Krylov method is used to solve the interface nodes between adjacent domains.<br>Drawback of the hybrid approach is that the time complexity of the iterative part linearly increases with<br>the number of RHS. In the following, we introduce the domain decomposition method before illustrating<br>its potentialities with 2D and 3D simulations.