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The Inversion of Full Waveform Sonic Data for Estimating Stiffness Elements and Azimuth of Transversely Isotropic Medium
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 80th EAGE Conference and Exhibition 2018, Jun 2018, Volume 2018, p.1 - 5
Abstract
The stiffness elements become complicated when the anisotropic formation has azimuth. It is concerned that the inversion would be unstable due to the increment of the number of unknown parameters. In this research, we suggested a new parameterization strategy which mitigates the instability. We introduced the orientation and dip as model parameters to estimate instead of estimating model as general elastic medium which has 21 independent parameters. Full waveform inversion (FWI) is an effective way to estimate the properties of formation with high accuracy. We applied the FWI to transversely isotropic medium in borehole model to estimate the 5 independent stiffness elements, orientation and dip. As a result, all elements get close to the true value by iterative process. In addition, the convergences of model parameters are verified by looking at the misfit plane. Misfit plane indicates the tendency of convergence and effectiveness of FWI. Our result suggests that the new parameterization and FWI has an advantage over the conventional methods in terms of accuracy and stability.