Injection and trapping of carbon dioxide in deep saline aquifers

Abstract

AbstractCarbon dioxide (CO2) collected from the waste streams of point sources can be injected into deep geologic formations in order to limit the emission of greenhouse gases to the atmosphere. Deep saline aquifers provide the largest potential subsurface storage capacity for injected CO2. Once injected, free CO2 can be retained in deep aquifers for long time periods by slow-moving, downward-directed formation waters. Over time, the injected CO2 will dissolve in the formation waters and, through reactions with formation minerals, may be converted to carbonate minerals, resulting in permanent sequestration. Factors that influence the mass of CO2 that can be injected and stored in free or aqueous form, and as mineral phases, are reviewed and applied to estimate storage capacity of the Rose Run Sandstone, a saline aquifer beneath eastern Ohio, USA. It is estimated that 30 years of CO2 emissions from five of Ohio’s largest coal-fired power plants can be injected into the Rose Run Sandstone and, over time, converted to aqueous and, ultimately, mineral phases.