A Quartic Traveltime Inversion Method for TTI Media and Applications on Anisotropic Migration and Fracture Prediction
X. Sun and S.Z. Sun
Event name: 76th EAGE Conference and Exhibition 2014
Session: Anisotropic Parameter Estimation - Theory
Publication date: 16 June 2014
Info: Extended abstract, PDF ( 1.31Mb )
Price: € 20
Currently, NMOz (Normal Moveout Versus Azimuth) plays an important role in anisotropy-related processing. It can also provide parameters required for both anisotropic migration and kinematic fracture prediction. However, NMOz algorithm is developed on the basis of the traveltime formula with a presumed hyperbolic moveout, which losses considerate accuracy due to the truncation of quartic moveout and thereby usually fails to describe kinematic behaviors at large offsets. In this paper, we present a concise and more accurate traveltime formula for TTI media (with a horizontal reflector) by incorporating quartic moveout, which is proven to be in better agreement with most routine VTI or HTI approximations. In practice, we apply the new traveltime formula into a fractured physical model and a carbonate reservoir. Results show that events of common-offset azimuthal CRP gather from anisotropic migration becomes more flattened and the reflection energy is also remarkably concentrated even for large offsets. Besides, predicted fracture intensity and strike both show a close tie to tectonic movements, which may helps a better understanding of fracture evolutions.