Stonewell

Vault GSL CCS LP is developing the Stonewell Project, a proposed Class VI carbon storage project in Marion County, Ohio, designed to capture and permanently sequester carbon dioxide from a nearby ethanol facility. The project plans to inject approximately 5.1 million tonnes of CO₂ over a 12 year operational period into the Cambrian-age Mt. Simon Sandstone, with an anticipated injection rate of approximately 425,000 tonnes per year. The project is centered around a single proposed Class VI injection well, Stonewell Injection Well 1 (STO INJ1), which is expected to be sufficient to handle the full injection volume due to the favorable reservoir properties of the formation. The primary storage reservoir is the Mt. Simon Sandstone, a regionally extensive deep saline formation that has been widely used for Class I, II, and Class VI injection operations across the Midwest. At the Stonewell site, the Mt. Simon Sandstone serves as the injection zone and is overlain by the Rome Formation, which acts as the primary confining zone. Additional regional seals include the Glenwood Shale, Utica Shale, and Queenston Formation/Maquoketa Group, providing multiple layers of vertical containment. The project area lies on the eastern flank of the Findlay Arch within Ohio’s Arches Province, a tectonically stable region with approximately 3,000 feet of Cambrian through Silurian sedimentary section. The project includes four primary wells consisting of one injection well, one deep observation well, one above-confining-zone monitoring well, and one USDW monitoring well to support long term monitoring and verification activities.