Anisotropy parameter inversion in vertical axis of symmetry media using diffractions

Anisotropy parameter inversion in vertical axis of symmetry media using diffractions

Umair bin Waheed, Alexey Stovas and Tariq Alkhalifah, "Anisotropy parameter inversion in vertical axis of symmetry media using diffractions", Geophysical Prospecting (2017):submitted.​​
Umair bin Waheed, Alexey Stovas, Tariq Alkhalifah
anisotropy, VTI, diffraction
2017
​Diffractions play a vital role in seismic processing as they can be utilized for highresolution imaging applications and analysis of subsurface medium properties like velocity. They are particularly valuable for anisotropic media as they inherently possess a wide range of dips necessary to resolve the angular dependence of velocity. However, until recently, the focus of diffraction imaging or inversion algorithms have been only on the isotropic approximation of the subsurface. Using diffracted waves, we develop a framework to invert for the effective η model. This effective model is obtained through scanning over possible effective η values and selecting the one that best fits the observed moveout curve for each diffractor location. The obtained effective η model is then converted to an interval η model using a Dix-type inversion formula. The inversion methodology holds the potential to reconstruct the true η model with sufficiently high accuracy and resolution properties. However, it relies on an accurate estimation of diffractor locations, which in turn requires good knowledge of the background velocity model. We test the effectiveness and applicability of our method on the vertical transverse isotropic Marmousi model. The inversion results yield a reasonable match even for the complex Marmousi model.
1365-2478