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Multi-parameter Joint Tomography for Anisotropic Model Building
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, May 2011, cp-238-00529
- ISBN: 978-90-73834-12-5
Abstract
This paper presents a multi-parameter joint inversion method to estimate the spatially varying updates for anisotropic parameters using P-wave reflection data. The proposed method can estimate up to three parameters: vertical velocity and the two Thomsen anisotropic parameters (ε and δ) for a vertical transverse isotropic (VTI) medium. For a tilted transverse isotropic (TTI) medium, the method assumes that the symmetry axis (tilted axis) of wave propagation is given. The proposed method has the flexibility to update only vertical velocities for a VTI medium or tilted velocities for a TTI medium keeping the other parameters fixed. To remove inherent ambiguities in the solution, we apply different preconditioning and regularizations to the velocity and anisotropic parameter updates. The method has been tested on both synthetic TTI data from the very complicated model and field data. The synthetic test yields a reliable tilted velocity model and reasonable values for the other two parameters. For the field data test, we use velocities from well logs as constraints. The updated model from the method results in flatter CRP gathers and remains consistent with the well information.