Intra-reservoir sand architecture delineation via depth domain modified cepstral decomposition “seismic resonance”

Abstract

In Gulf of Mexico deep water turbiditic fields, one seismic event may correspond to multiple vertically stacked sand flow units separated by thin-bed shale breaks. Delineation of such intra-reservoir architecture is important especially for injector/infill planning and reservoir management in water flooded fields. For example, if only one or two of the sand units are flooded while the rest of the sand units are still unflooded, they could be targeted for infill drilling or injector placement. However, such fine resolution details within a seismic loop are usually difficult to resolve or unresolvable by traditional seismic interpretation and inversion techniques. In this extended abstract, I demonstrate that sub-resolution shale break reflectors could be identified via a modified cepstral decomposition, “seismic resonance”. This decomposition is carried out in the depth domain to avoid sampling issues arise from depth to time and again time to depth conversion. The result shows that the technique can effectively resolve multiple key sub-resolution reflectors in wells that are 40 ft (∼8 ms) apart at minimum from each other in a seismic data with tuning thickness of 120 ft. Application of this technique to a Kirchhoff migrated OBN data revealed intra-reservoir sand architecture in studied area that agrees with well data, reservoir performance and 4D seismic observations, which feeds into reservoir modeling and management decisions. Note: This paper was accepted into the Technical Program but was not presented at IMAGE 2021 in Denver, Colorado.