Outcrop-Based Sequence Stratigraphy and Reservoir Characterization of an Upper Mississippian Mixed Carbonate-Siliciclastic Ramp, Mayes County, Oklahoma

Abstract

While Osagean and Kinderhookian strata have been closely studied using biostratigraphy, lithostratigraphy, and sequence stratigraphy, little work has been completed on the Meramecian and Chesterian strata of Oklahoma and Kansas. This study proposes a depositional model, sequence stratigraphic framework, and 3-D outcrop model for Upper Mississippian strata exposed in Mayes County, Oklahoma.

Facies shoal upwards from lowstand clay-rich wackestones and siltstones to progressively more carbonate-dominated facies, terminating in mud-lean skeletal packstones to grainstones. The sequence stratigraphic hierarchy present at the studied outcrop consists of two partial 3rd-order composite sequences (1-10 m.y.) constrained by biostratigraphy that are made up of probable 4th-order high frequency sequences (100 or 400 k.y.). Facies, sedimentary structures, and bed geometries observed in outcrop indicate deposition within the ramp crest to outer ramp portion of a distally-steepened ramp during various fluctuations in sea level.

Utilizing photogrammetry to stitch and geo-reference high-resolution aerial photos, 3-D representations of outcropping walls and pavement can be created at a sub-meter resolution, and can serve as valuable tools for the visualization of bed and facies relationships in 3-D space. Drone-based aerial and orthogonal photography can be used to capture images and create 3-D models of dangerous or otherwise inaccessible outcrop areas. These models can be directly imported as base surfaces to reservoir modeling software, where they can be integrated with petrographic and sequence stratigraphic data to model facies, porosity, and permeability relationships. Petrel-based facies and porosity models illustrate the lateral and vertical variability that exists in outcrop while providing detailed approximations of subsurface reservoir heterogeneity.