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Advanced Workflows Coupled with Quantitative Interpretation: Improving Prospect Structural Delineation

Abstract

Recent advances in software development have enabled seamless integration of prestack data with advanced attributes and high-end interpretation and visualization workflows. We describe a new approach that gives geophysicists and geologists more flexibility in checking the quality of prestack data and helping to create and investigate customized seismic stacks. This approach, coupled with advanced attributes, 3D interpretation and visualization functionalities, significantly improves the structural delineation of a prospect. We begin by decomposing the prestack data by angle and then applying specific seismic attributes to each angle stack to highlight the structure. For example, multitrace attributes like variance and Ant Tracking are applied to each angle stack. As a result, the comparison reveals that the near-angle stack is the most appropriate to highlight faults. Clear identification of faults allows interpreting the reservoir top and base. Again, the different-angle stacks show various qualities in terms of reflector continuity. In this case, the mid-angle stack appears to be the best to highlight the top and base of the reservoir. This novel approach combines two types of information—the faults defined from the near-angle stack, and the best seismic amplitude from the mid-angle stack—into a single hybrid seismic cube. With this cube, any reflector can be automatically picked from the mid-angle stack amplitude with the constraint to stop at the faults detected on the near-angle stack. This yields impressive results while using automated tracking to strictly follow faulted corridors. This automated-tracking interpretation is performed without interpreting any single fault. Lastly, the resulting top- and base-faulted horizons are gridded and used to create a surface 3D probe where faults are visually removed, which gives a realistic 3D view of the prospect and its complex compartmentalization. This paper demonstrates that combining prestack seismic data with advanced multitrace attributes and visualization workflows significantly improves the structural delineation of a prospect.