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Approximate Data-Domain Hessian in Extended-Source Time-Domain Full Waveform Inversion Using Matching Filter and Conjugate Gradient Method
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 83rd EAGE Annual Conference & Exhibition, Jun 2022, Volume 2022, p.1 - 5
Abstract
Wavefield reconstruction inversion (WRI) avoids cycle-skipping in full-waveform inversion (FWI) by computing wavefields with wave-equation errors (i.e., source extensions) such that simulated data closely match observed data with inaccurate velocity models. %However, the implementation of time-domain WRI faces a practical challenge because the source extension in the right-hand side of the wave equation depends on the unknown data residuals.
Recent studies show that source extensions are the least-squares solutions of the scattered-data (i.e., FWI data residuals) fitting problem for contrast-source estimation. As a result, source extensions are computed by propagating backward in time the deblurred FWI data residuals, where the deblurring operator is the inverse of the damped data-domain Hessian of the contrast-source estimation problem. We first estimate an approximate deblurring operator with matching filter, which can be used as a preconditioner for iterative refinement of the source extensions with a conjugate gradient method. Numerical tests validate the proposed scheme for accurate reconstruction of contrasted media from crude initial model.