HIGH RESOLUTION BASIN MODELING OF THE PERMIAN CAPITAN REEF, NEW MEXICO: NEW INSIGHT FROM INTEGRATED OUTCROP LIDAR-XRF-SGR ANALYSIS INTO REEF ARCHITECTURE

The classic paradigm for Capitan Permian reef architecture and growth in the Guadalupe Mountains of New Mexico portrays continuous progradation and aggradation until the onset of the Ochoan with increasing steepening of the associated downdip talus. The results of integrated LiDAR (Light Detection and Ranging), XRF (X-ray Fluorescence) and SGR (Spectral Gamma Ray) analysis of the ~3 km long by ~1 km high eastern wall of Slaughter Canyon input into a high resolution basin model challenge this paradigm. When constrained by the XRF and SGR data, LiDAR reflectivity reveals eight separate sponge bioherms. Varying thicknesses of allochthonous carbonate cycles with enriched clastic sediment punctuate bioherm growth. The oscillations in reef growth correspond to high stand systems tract times on a constructed Relative Sea Level Curve which matches that of the Saudi Aramco sea level curve for the Permian Arabian Platform. The breaks in bioherm growth may indicate times of Delaware Basin lowstands owing to pulsed closures of the Hovie Channel and/or global sea level falls. 76 virtual wells were developed from the XRF-SGR constrained LiDAR stratigraphy along the canyon wall in order to model the effects of compaction and its role in reefal steepening. The subsequent high resolution 2D subsidence models, constructed at ~0.25-0.5 ma intervals, reveal alternating reef and associated talus dip angles for decompacted and compacted sediments from gentle to steep to gentle which dramatically influence the antecedent topography of overlying beds. The decompacted low energy muddy boundstone bioherms are located downdip of high energy back reef shoaling facies, defining the overall architecture as a shoal rimmed platform.