Abstract

Observations from outcrop offer insight into Freservoir geometry that may be used to better understand subsurface stratigraphic architecture. Prediction of reservoir sweet-spots in steep-slope systems for both conventional and unconventional production is frequently hindered by poor seismic resolution, sub-seismic and inter-well heterogeneity, and a lack of understanding of how steep-slope systems respond to relative sea-level. Prediction of stratigraphic packaging within the Permian Basin may offer significant savings in production cost through optimization of completion techniques that focus on the most productive zones of the target interval.

Measured stratigraphic sections, field mapping, high-resolution, airborne-lidar interpretation, and spectral-image analysis were integrated into a 3-D GIS database and used to extract relationships between channel positions and fill types along Upper Permian (Guadalupian) paleoslopes between Pine and McKittrick Canyons in Guadalupe Mountains National Park. Exposures of the Bell Canyon/Capitan Formations offer multiple windows into the transition between proximal mid-to-lower slope carbonate debris and more distal siliciclastic slope-channel successions. Outcrop observations were used to reconstruct the lower slope to basin profile and channel geometries for distal equivalents of the steep, high-relief Capitan reef and foreslope systems. These channel systems are best exposed within the middle Yates Formation, when progradation to aggradation ratios are highest.

The turbidity currents responsible for channel incision into the lower-slope equivalents of the Capitan clinothems were most active during relative sea-level lowstand when siliciclastic material bypassed the slope and deposited many tens of kilometers out in the basin. After active channelization waned, lower-slope channels were back filled by amalgamated margin-derived carbonate debrites (Rader Member megabreccia) followed by platform-top-derived grain-dominated carbonates with low concentration of siliciclastic matrix material.

The mixed carbonate and siliciclastic deposits preserved in the Guadalupe Mountains offer clues to help better understand the timing of coarse carbonate sediment delivery into the lower slope-to-proximal basin setting. Knowledge gained from this outcrop study may improve predictive capability in the subsurface assets of the Permian Basin and systems with similar geometry and sediment type that are targets for exploration and production in unconventional resource plays.