Effective reflection coefficients for seismic wavefields at curved interfaces E.Z. Rakshaeva 1,2, T.V. Nefedkina 2, A.M. Aizenberg 2, R.I. Vilegzhanin 1, P.A. Lykhin 1 1 Novosibirsk State University, Russia 2 Institute of Petroleum Geology and Geophysics, Russian Academy of Science, Russia.

Plane-wave reflection coefficients (PWRC) Assumption 1. planarity of wavefront Assumption 2. planarity of reflector at frequency omega tends to infinity u u P (x)

Spherical wave reflection coefficients [Cerveny and Hron,1961] Assumption 2. planarity of reflector at frequency omega tends to infinity Is it known that both interface curvatures affect the size of the Fresnel zone and cannot be neglected [Favretto-Cristini et al., 2009]

s Effective reflection coefficient (ERC) [Ayzenberg et al, 2007,2011], [Rakshaeva et al, SEG, 2014]

Poster plan Introduction Effective reflection coefficients At interface At receiver Applications: Seismic modeling ERC-based AVO inversion Conclusions 76 th EAGE Conference & Exhibition 2014

Overview We propose an accurate way to model reflection data at curved reflectors, which is based on the ERC. The ERC is numerically stable and capable of simulating complex wave phenomena, such as near-critical, post-critical, and head waves at curved reflectors. Such ERCs exhibit a real accounting for strong front astigmatism and reflectors with noticeable elongation. A comparison of the AVO inversion of long-offsets results obtained with our approach and the results from an AVO inversion method based on PWRC and SpRC are illustrated..

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