Abstract

Production-scale variability in Mississippian reservoirs of the U.S. Mid-Continent is poorly understood, largely due to distant spacing of subsurface wells and the lack of outcrops that provide a 3-D distribution of potential reservoir facies. This study utilizes exposures of Upper Mississippian (Meramecian to Chesterian in age) lithofacies in a quarry to develop a first order 3-D facies model at a production or enhanced-production scale (<40 ac; <16.2 ha). By utilizing photogrammetry to stitch and geo-reference high-resolution aerial photos, 3-D representations of outcropping walls were created at a sub-meter resolution, and serve as valuable tools for the visualization of bed and facies relationships in 3-D space. Drone-based aerial and orthogonal photography was used to capture images and create 3-D models of inaccessible outcrop areas. These models were imported as base surfaces to geostatistical reservoir modeling software (Petrel), in which they were integrated with petrographic and sequence stratigraphic data to model facies and porosity relationships. Various algorithms and variogram lengths were tested and compared to high resolution outcrop data to determine the most appropriate workflow for future subsurface modeling. The Petrel-based facies and porosity models illustrate the lateral and vertical variability that exists in outcrop while providing detailed approximations of subsurface reservoir heterogeneity.