Assessment of Factors Influencing CO2 Storage Capacity and Injectivity in Eastern U.S. Gas Shales

This article delves into a study, funded by the U.S. Department of Energy, which investigates the capacity of organic-rich gas shales, specifically the Marcellus Shale in the Eastern United States, for simultaneous CO2 storage and methane recovery. Similar in behavior to coal, these shales release methane and preferentially absorb CO2. The research estimates that the Marcellus Shale could theoretically replace all its methane, whether adsorbed or in "free" form, with injected CO2. The total projected maximum CO2 storage capacity stands at about 1.12 million metric tonnes per square kilometer (MMt/km2).

To assess the feasibility and dynamics of this storage, the researchers undertook comprehensive geological and reservoir characterizations. Detailed simulations were then executed, focusing on areas ideal for CO2 storage, based on factors like reservoir conditions, shale thickness, and current gas extraction activities. The simulations aimed to predict CO2 injection rates, the potential increase in methane yield, and the behavior of CO2 in the reservoir over time. This research could pave the way for dual benefits in shale regions: enhanced methane recovery and effective CO2 storage.