Fluvial architecture of the Burro Canyon Formation using UAV-based photogrammetry and outcrop-based modeling: implications for reservoir performance, Rattlesnake Canyon, southwestern Piceance Basin, Colorado

Abstract

The stratigraphic variability of fluvial architectural elements and their internal lithological and petrophysical heterogeneity influence static connectivity and fluid flow. Analysis of the fluvial architecture and facies heterogeneity of the Lower Cretaceous Burro Canyon Formation provides insight regarding their impact on reservoir performance. The Burro Canyon Formation as exposed in Rattlesnake Canyon, Colorado, forms stacked amalgamated and semi-amalgamated channel complexes that consist of amalgamated and isolated fluvial-bar channel deposits and floodplain fines, and represents a perennial, braidedfluvial system. Detailed two(2-D) and three-dimensional (3-D) static and dynamic reservoir models are constrained using stratigraphic measured sections, outcrop gamma-ray measurements, and Unmanned Aerial Vehicle (UAV)-based photogrammetry. Resulting breakthrough time and sweep efficiency suggest subsurface reservoir performance is most effective perpendicular to paleoflow direction in amalgamated channels. Perpendicular to paleoflow, breakthrough time is 9% shorter than parallel to the paleoflow and sweep efficiency is, on average, 16% greater due to greater sandstone connectivity in this orientation. Variability of preserved channels and lateral pitchouts results in lower recovery efficiency. Facies heterogeneity can account for 50% variation in breakthrough time and slightly lower recovery efficiency (5%). Cemented conglomerates that form channel lags above basal scour surfaces can also create fluid-flow barriers that increase breakthrough time and decrease sweep efficiency (25%) and recovery efficiency (22%).