Like the Arbuckle Group, the Ordovician reservoirs and Hunton Group in Oklahoma exist over most of the state, at depths adequate for carbon capture, utilization, and storage. The Ordovician reservoirs (Ordovician zone) include the Viola Limestone and Simpson Group and lie above the Arbuckle Group. The Silurian–Devonian-age Hunton Group lies directly above the Sylvan Shale, a hydrocarbon seal for the Lower Ordovician reservoir, and is sealed by the overlying Woodford Shale. Although there has been significant research on these reservoirs for their hydrocarbon potential, there have been no regional studies showing the distribution of lithologies, pore volume, and their CO₂ storage resources.

Using well information from 80,800 wells for the structural model and more than 1126 wells with log ASCII standard format with modern well logs, a detailed three-dimensional lithology model was built for the Ordovician and Hunton zones across the state of Oklahoma. Total porosity was then calculated from well logs, and the total porosity model was constrained to the lithology model. To determine the CO₂ storage resources, the US Department of Energy’s methodology was applied. The total CO₂ storage resources for the Ordovician and Hunton range between 6501 and 20,877 million metric tons (Mt) and 1331 and 3094 Mt, respectively, with 35% of the Ordovician sandstones and 17% of the Hunton zone accessible at depths of less than 10,000 ft (3048 m).