Similarity attributes from differential resolution components

Abstract

Seismic resolution plays an important role in the delineation of structural and stratigraphic features. The resolution improvement directly affects the seismic attributes and, consequently, the interpretation of a given feature. However, the broadband data do not necessarily provide the best insight for seismic attribute evaluation. Particularly, geologic discontinuities, such as karsts, faults, and fractures, can have different seismic expressions according to their intrinsic scales, and, therefore, they are better illuminated in a given frequency range. To extract dissimilar characteristics in different frequency bands, we have combined a recently developed spectral enhancement method based on differential resolution (DR) and similarity attributes. The DR algorithm is simultaneously used for frequency enhancement and acting as a pseudofilter, allowing us to compute similarity attributes at different frequency bands. The similarity computation follows the reflector dip of each DR subband and adjusts its analysis window accordingly to the dominant frequency within the subbands. Then, the subband similarities are combined in the red-green-blue-alpha color space, allowing a more detailed view of the geology under investigation. Although more expensive in terms of processing time because of all the steps needed for each subband, the proposed strategy proved to be a great improvement over the conventional procedure of detecting and delineating discontinuities in fault and karst structures when treating seismic data from an offshore carbonate field in Campos Basin, Brazil.