Defining CO2 Geological Storage Capacity in Unmineable Coal Seams Through Adsorption Data in 3D: Case Study of the Chico Lomã Deposit, Southern Brazil

The concentration of greenhouse gases in the atmosphere has led to irreversible climate changes, emphasizing the need for effective strategies to mitigate emissions. Carbon capture, utilization, and storage (CCUS) technologies, including geological CO2 storage, have gained recognition worldwide due to their potential for CO2 emissions abatement. Among potential geological reservoirs, coal seams are significant due to their efficiency in securing CO2 storage, through their adsorption storage capacity. This study presents an innovative methodology for estimating the theoretical CO2 storage capacity in unmineable coal seams, focusing on the Chico Lomã deposit in southern Brazil. The methodology integrates a comprehensive drillhole database and adsorption isotherm data to define the coal reservoir zone and calculate its CO2 storage capacity. The results indicate a total theoretical CO2 storage capacity of 47.8 Gt in the Chico Lomã deposit, with the potential to mitigate emissions from local thermoelectric plants for over 500 years. The study encourages the application of the proposed methodology to assess CO2 storage capacity in other unmineable coal deposits worldwide.