Diffraction traveltime approximation for TI media with an inhomogeneous background
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Earth Science and Engineering Program
Environmental Science and Engineering Program
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AbstractDiffractions in seismic data contain valuable information that can help improve our modeling capability for better imaging of the subsurface. They are especially useful for anisotropic media because they inherently possess a wide range of dips necessary to resolve the angular dependence of velocity. We develop a scheme for diffraction traveltime computations based on perturbation of the anellipticity anisotropy parameter for transversely isotropic media with tilted axis of symmetry (TTI). The expansion, therefore, uses an elliptically anisotropic medium with tilt as the background model. This formulation has advantages on two fronts: first, it alleviates the computational complexity associated with solving the TTI eikonal equation, and second, it provides a mechanism to scan for the best-fitting anellipticity parameter η without the need for repetitive modeling of traveltimes, because the traveltime coefficients of the expansion are independent of the perturbed parameter η. The accuracy of such an expansion is further enhanced by the use of Shanks transform. We established the effectiveness of the proposed formulation with tests on a homogeneous TTI model and complex media such as the Marmousi and BP models.
SponsorsWe would like to thank KAUST and ROSE project for financial support. We also extend thanks to BP for releasing the benchmark synthetic model. We acknowledge useful discussions with David Ketcheson on implementing the TTI eikonal solver. We are extremely grateful to Claudia Vanelle, Stig-Kyrre Foss, Zvi Koren, and Sergius Dell for useful reviews that improved the quality of the paper.
PublisherSociety of Exploration Geophysicists