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Seismic Geomorphology of Permian Shelf Margin, Slope and Basin in the Northern Delaware Basin

Abstract

A high-quality 3D seismic volume in the NW Delaware Basin reveals a complex stratigraphic architecture of key producing intervals in the Permian Basin. The 3D volume, combined with regional 2D seismic lines, enabled the interpretation of a reference stratigraphic cross-section for the Northern Delaware Basin. The north-to-south 2D seismic line shows the regional stratigraphic architecture of the Wolfcampian to Guadalupian shelf margin and allows us to relate the slope to basin strata imaged in the 3D seismic to the well-established platform stratigraphic architecture. The 3D seismic volume reveals the seismic geomorphology of several key intervals. In the Wolfcampian, a large carbonate channel-to-fan complex developed on the footwall of a NE-SW oriented fault and is well imaged using RMS amplitude attributes on horizons. In the overlying Bone Spring interval, multiple lobate amplitude anomalies are interpreted as laterally offset fan systems. The RMS amplitude stratigraphic slice shows evidence of a low sinuosity, down-dip elongated amplitude anomaly interpreted as channels in the Bone Spring interval. The best seismic expression of channels and fan are found in the Delaware Mountain Group, where stratal slices reveal spectacular low sinuosity, large channels as well as more frequents narrower, more sinuous channels. The Upper part of the Brushy Canyon shows numerous narrow sinuous channel that are organized in a down dip convergent pattern associated with lobate amplitude anomalies that are interpreted as a fan complexes. In the slope interval associated with the Early Capitanian reef on the 2D sections, down-dip convergent low sinuosity channel are associated with the steeper carbonate reefal margin. Finally, the prograding Capitanian margin is imaged in the 3D volume showing spectacular seismic geomorphology of the very irregular reef margin and the associated straight gullies on the upper slope. The highly irregular reef margin shows a reentrant and promontory morphology feature that extends up to 10 km into the basin and potentially one isolated reef pinnacle. Finally, the 3D seismic volume displays strong evidence of evaporitic karst dissolution in the Capitanian shelf interior and spectacular folds associated with the post depositional deformation of the Castille evaporites. Overall, this new seismic survey provides a fantastic but complex view of the geomorphology of the basinal to slope Permian strata that significantly improves our conceptual models of the Permian carbonate, siliciclastic and mixed carbonate-siliciclastic intervals in the Delaware Basin.