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AVO INVERSION OF LONG-OFFSET SYNTHETIC PP DATA BASED ON EFFECTIVE REFLECTION COEFFICIENTS. Lyubov Skopintseva Milana Ayzenberg, Martin Landrø Tatyana Nefedkina, Arkady Aizenberg. 10 April 2008. AVO- analysis . What is that ?. Conventional AVO analysis:
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AVO INVERSION OF LONG-OFFSET SYNTHETIC PP DATA BASED ON EFFECTIVE REFLECTION COEFFICIENTS Lyubov Skopintseva Milana Ayzenberg, Martin Landrø Tatyana Nefedkina, Arkady Aizenberg 10 April 2008
AVO-analysis. What is that? • Conventional AVO analysis: • Range of incidence angles: 0-400 • Weak contrasts at reflector
Plane-wave reflection coefficient Post-critical region Critical angle Pre-critical region
Effective reflection coefficient (ERC) Incident wave Plane-wave decomposition Multiplying by plane-wave reflection coefficient (PWRC) Summation Division by incident wave
ERC versus PWRC • PWRC valid for plane waves • ERC generalize PWRC for point sources - incidence angle - frequency - wavefront curvature - wave velocity
Cost functions comparison (pre-critical offsets) Effective reflection coefficient Plane-wave reflection coefficient
Cost functions comparison (all offsets) Effective reflection coefficient Plane-wave reflection coefficient
AVO inversion results ERC solution PWRC solution
Conclusion • ERC give better estimates than PWRC • Rapid variations in reflection amplitude for post-critical offsets improve inversion results • Long-offset data allow accurate estimation of Vp and Vs