GEOCHEMICAL EVALUATION OF CLAY-RICH INTERVALS IN THE CHERRY CANYON FORMATION IN THE DELAWARE BASIN OF TEXAS

In the Permian Basin of West Texas and Southeastern New Mexico, the late Permian Delaware Mountain Group (DMG) has been a target for Carbon Capture, Utilization, and Storage (CCUS) activities including Enhanced Oil Recovery (EOR) utilizing CO2 and disposal of acid gas with variable hydrogen sulfide (H2S) and CO2 content. The 4,500-ft-thick (1,375 m) DMG is divided into the Bell Canyon, Cherry Canyon, and Brushy Canyon formations, which are arkosic sandstone, siltstone, and carbonate debris flows deposited in submarine fan complexes in the Delaware Basin. Detrital clay minerals are not commonly associated with the DMG sediments, however authigenic illite and chlorite are commonly found. The Cherry Canyon Formation reservoirs are found where sandstone facies pinch out laterally to calcite cemented siltstone and carbonate debris flows. Zones of tightly cemented siltstone and skeletal debrites provide further baffles to flow in the Cherry Canyon Fm. Recent work on the Cherry Canyon in the Ford-Geraldine Field in the Delaware Basin identified illite, smectite, chlorite, and mixed-layer clays coating grains and lining pores. The presence of these authigenic mineral phases increases reservoir compartmentalization which may favor carbon storage efforts in the Cherry Canyon Formation.

Here, we evaluate the lower Cherry Canyon Formation in a wildcat well from Reeves County, TX. The Timber/Sharp #2-22 Ligon State core (6377 – 6540.4 ft below surface) contains 163.4 ft (49.8 m) of core from the South Wells Member of the formation. The core can be divided into three intervals: an interval of swelling clays, a tectonic interval with soft sediment deformation, high angle blocks and overturned beds, and a “classic” lower Cherry Canyon interval of mixed sandstones and thinly laminated siltstones. Porosity in the core ranges from 5% to 20% with permeability between 0.2 md and 39 md. The core was scanned with a portable X-ray fluorescence (XRF) spectrometer at 0.1 ft (3 cm) intervals to evaluate geochemical changes recorded in the sediments. Preliminary analysis of the XRF data indicates the intervals of swelling clays can be identified by elevated Sr, Mg, and Ca concentrations and suggests the presence of chlorite-smectite clays in the core. Evaluation of clay mineral phases in the core with Scanning Electron Microcopy with Energy Dispersive X-ray (SEM-EDS) analysis is ongoing.