95-8 Integrated Seismic and Outcrop Characterization of Pore Space for Wastewater Injection in the Delaware Mountain Group, Delaware Basin

Session: Sustainable Subsurface Pore Space Utilization: Site Selection, Characterization, and Modeling

Presenting Author:

Authors:

Abstract:

The growing interest in siliciclastic reservoirs for subsurface injection and storage in energy systems has underscored the need to understand how these formations respond and evolve during fluid injection. The Delaware Mountain Group (DMG) in the Delaware Basin of West Texas and southeastern New Mexico offers an ideal natural laboratory for such studies, currently receiving the injection of approximately 7 million barrels per day of unconventional oilfield wastewater. To investigate the behavior of the DMG injection interval, we analyze a high-resolution 3D seismic survey alongside nearby outcrop data, revealing the group’s complex deep-marine stratigraphic architecture and basin-fill history. The seismic interpretation of lithofacies and reservoir characteristics forms the foundation for evaluating the storage potential of the group and guiding long-term reservoir management, insights that are broadly applicable to other large-scale underground injection systems.

Analysis of multiple seismic attributes and isochore mapping indicates an overall westward shift in basin floor deposition through time. At the base of the DMG, channel systems range from weakly confined channels to broad lobe complexes, likely extending beyond the seismic footprint. The middle interval is dominated by highly erosive, moderately to strongly avulsive distributary channels interbedded with thick, laterally extensive distal lobes. Toward the top of the interval, more sinuous and moderately confined channels are accompanied by elongated lobe systems. We observe a progressive narrowing of channel width upward in the stratigraphy, from an average of 700 meters in the lower and middle intervals to approximately 300 meters in the upper section. This stratigraphic pattern is supported by prior studies and our drone-based outcrop mapping, which confirm confined channel systems eroding into underlying lobe complexes in the upper DMG.

By combining petrophysical analyses from approximately 300 well logs across the mid-central Delaware Basin with our seismic and outcrop interpretations, we construct regional models of reservoir distribution and properties. The integration of seismic facies interpretations with outcrop analogs provides a framework for distributing lithofacies and porosity across the basin. This high-resolution approach enables more accurate pore space calculations and establishes a foundation for assessing the original and potential remaining storage capacity of the DMG system which is essential for understanding the utilization of this strata as an ongoing injection resource.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-5994

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