Low-frequency upscaling in high-contrast media with application to TTI media

Summary In this paper, an extension of low-frequency upscaling methods to handle more complicated media is developed. Increased variability and anisotropy with a tilted symmetry axis (TTI) are now handled. We show that strong contrasts in elastic properties have a dramatic effect on seismic upscaling regardless of anisotropy. In particular, the lowfrequency upscaling method (Stovas et al., 2013) developed for isotropic and transversely isotropic media does not work due to discontinuities in the effective slowness surface. In this case, the application of a new method is required. The vertical energy flux computed for the stack of layers can be considered as an AVO signature for the overburden. The new upscaling methods are also defined for a tilted TI medium. The developed methods are tested on a real dataset from the Faroes-Shetland Basin.