3D fault imaging using windowed Radon transforms: an example from the North Sea
The interpretation of fault surfaces is key to understanding the subsurface geology represented in 3D seismic volumes. The geologic structure represented by seismic reflections can be auto-tracked in the volume. Faults, however, are imaged as discontinuities or changes in curvature in the seismic data. For many years, fault interpretation involved manually picking fault cuts on orthogonal slices through the seismic volume. These fault cuts were grouped into conceptual faults, and 3D fault surfaces were created from the fault cuts. In the 1990s, the development of attributes to highlight discontinuities in 3D seismic data was pervasive in the industry. Perhaps the most well known of these efforts was the development of Coherence (Bahorich and Farmer, 1995; Gersztenkorn and Marfurt, 1996; Marfurt, et al., 1999). Although coherence or edge attributes highlighted faults in the seismic volume, the fault imaging was insufficient to support automatic extraction of the fault surfaces. These attributes provided guidance to the manual interpretation of faults in the 3D volumes. This paper describes a portion of the history behind the development of techniques to improve 3D fault imaging to the point where fault surfaces can be automatically extracted from seismic volumes. A windowed Radon transform-based technique is then described and applied to the F3 survey from the North Sea. This technique produces fault images that are of sufficient quality to support automatic extraction.