Underground geological storage

Abstract

Underground accumulation of carbon dioxide (CO2 ) is a widespread geological phenomenon, with natural trapping of CO2 in underground reservoirs. Information and experience gained from the injection and/or storage of CO2 from a large number of existing enhanced oil recovery (EOR) and acid gas projects, as well as from the Sleipner, Weyburn and In Salah projects, indicate that it is feasible to store CO2 in geological formations as a CO2 mitigation option. Industrial analogues, including underground natural gas storage projects around the world and acid gas injection projects, provide additional indications that CO2 can be safely injected and stored at well-characterized and properly managed sites. While there are differences between natural accumulations and engineered storage, injecting CO2 into deep geological formations at carefully selected sites can store it underground for long periods of time: it is considered likely that 99% or more of the injected CO2 will be retained for 1000 years.