Mapping Seismic Damage Zones Using Seismic Attributes
Nowadays most interpretation models proposed within basin and reservoir systems assume and simplify the seismic representations of structures as simple lines or surface strands. Faults are commonly picked as a single plane or a sharp discontinuity through the center of the fault.
Similarly, in compression systems, Deepwater toe thrust anticlines have been interpreted using traditional simplistic models such as fault-propagation folds, detachment folds, and both simple- and pure-shear fault bend folds. Even in very high quality 3D seismic lines the thrust anticline structures are often represented by wipe out zones that are critical to determining the trap elements in compression thrust system. Drilling in such a zones disclosed a much more complicated picture of the thrust and zones system. Exploration success in the offshore fold belts depends on understanding and visualizing their architecture and those low signal/noise zones using specific seismic attributes. A detailed and correct 3D visualization of their architecture represents a necessary step toward a correct conduit-reservoir -cap rocks characterization. A specific study focusing on the seismic image processing and mapping of fault distortion zone called Seismic Damage Zones (SDZ) within thrust fault and fold system is still lacking in the literature. In this paper we describe specifically the main image processing workflow and underline the potential of combining seismic attributes through volume visualization techniques to describe, map and highlight some deformation properties of the SDZ at the seismic resolution (10 to 100 m). By using the 3D image processing and data analysis tools available to us in this software, we applied a computational workflow to our 3D poststack seismic dataset. We will briefly describe the algorithms applied at each stage in the context of improving oriented structures, their interpretation and understanding within the single thrust fault system being studied. As a result of the post stack seismic image processing we investigated discontinuities using semblance attributes (that quantify and delineate the short-range anomalies on the intensity of reflector amplitudes,), spectral decomposition collecting these into so-called “disturbance geobodies” and proposed a possible workflow to detect deformation in low signal/noise zones bounding the thrust and main forelimb.
AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California