Schema for regional evaluation supporting class VI well applications in the Arbuckle Group of Kansas

Abstract An integrated, basin-scale methodology was developed to screen areas for geologic carbon storage in Kansas, focusing on the Arbuckle Group – the principal candidate for large-scale carbon capture and storage (CCS) in the U.S. Midcontinent. This approach is fit-for-purpose at the pre-Class VI stage, providing a defensible, regional framework to support early decision-making before undertaking more detailed site-specific characterization. The methodology integrates a faulted framework geocellular property model with spatial chance-of-adequacy (COA) evaluation for four fundamental CCS play elements: reservoir presence, reservoir quality, reservoir seal, and CO 2 phase state. By combining elements at the basin scale, the workflow identifies areas with favorable geologic conditions and estimates effective storage resource ranges at the formation scale. Legacy data spanning a century were evaluated for confidence, enabling differentiation between areas with robust screening results and those where additional data could materially change CCS potential. Results support significant CO 2 storage potential across Kansas, with effective storage resource estimates ranging from ~ 24–75 Gt statewide with a best estimate of ~ 39 Gt. Areas with high aggregate COA values align with previous Kansas Geological Survey CCS assessments, reinforcing confidence in the statewide screening outcomes. Importantly, this regional evaluation establishes the regional geologic framework and trends that can support Class VI site selection, where detailed stratigraphic, structural, geochemical, and geomechanical analyses are mandatory. State-led, publicly accessible regional subsurface evaluations provide a neutral, basin-wide framework that frames subsurface uncertainty, improves technical communication, can be leveraged for Class VI applications, and may accelerate CCS project development and enable long-term carbon storage planning.