Carbon Storage in Fold‐and‐Thrust Belts: An Overlooked Gigatonne Storage Opportunity

This study presents numerical investigations of the trapping characteristics of fold‐and‐thrust belt structures, defining three carbon capture and storage (CCS) play types that could be used to store commercial volumes (millions of tonnes) of CO2. Specifically, we present simulations of CO2 storage in three fold‐and‐thrust belt models comprising a thrust‐ramp, duplex, and thrust‐fold geometry. To constrain these play types in realistic geology, each model is based on a study site, including a novel investigation of a greenfield saline reservoir in Virginia, USA, being considered for commercial carbon storage and two well‐characterized petroleum fields: the Wilburton field in Oklahoma, USA, and the Incahuasi field in Bolivia. Our results provide insight into several key parameters, such as the long‐term security of injected CO2 in these geologies and injection strategies for maximizing storage efficiency while reducing pressure‐related risk. These results improve the understanding of CCS in fold‐and‐thrust belt storage sites globally by describing general storage parameters that may be applied to site‐specific projects. We find that thrust‐ramp geometries may securely trap CO2 through solubility and hydrodynamic trapping under suitable reservoir conditions, duplex structures may store some quantities of CO2 but are pressure‐constrained, and that thrust‐ramp structures may store large quantities of CO2 by maximizing fetch volume, which simultaneously lowers geomechanical risk by reducing pressure buildup along zones of weakness.