HORIZON SLICE OF BANDWIDTH-ENHANCED SEISMIC DATA FOR THIN BEDS AUTOTRACKED FROM SPECTRAL DECOMPOSITION

The horizon slice along the target horizon can provide a more accurate image of the paleo-depositional surface than the horizon-parallel and stratal (or proportional) slices if the target horizon can be readily interpreted. Fourth-order sequences in the northern central Miocene Gulf of Mexico, embedded in the deformed strata with significant lateral thickness variations, are at or below seismic resolution, making it difficult to interpret. In this study, we first improved the resolution of the seismic data from the northern central Gulf of Mexico by the bandwidth-enhancement technique. Then, a Miocene fourth-order sequence (M4) was autotracked through the 50-Hz isofrequency volume obtained by the generalized spectral decomposition of the enhanced data. The horizon slice along M4 through the enhanced data provides a much better image for incised valleys and distributary channels compared with the stratal slice through the original data reported by earlier work. The coblended image of the variance and amplitude horizon slices even better highlights the depositional features of M4. The horizon slice of M4 through the acoustic impedance volume, computed from post-stack inversion, shows that the incised-valley fill is characterized by low impedance, suggesting good reservoir quality and that the distributary-channel fill is characterized by low to moderate impedance, suggesting fair to good reservoir quality.