Natural analogues and test sites for CO2 geological sequestration: experience at Latera, Italy.

Field and laboratory experiments, combined with computer models, are the most common tools applied to the study of how human-engineered geological systems may evolve over time. However, this approach cannot accurately represent and understand processes that occur over geological time periods, on large scales, and within complex, heterogeneous geological set¬tings. The study of natural systems similar to those planned for man-made systems can provide some of this missing informationMost natural analogues of CO2 storage can be divided into two broad categories, those which are well sealed and those which leak. The study of both analogue types can yield valuable information needed to create well-isolated and intrinsically-safe CO2 geological storage sites For example, both offshore and onshore sites can help define deep- and near-surface migration pathways, travel times, and reaction-attenuation processes, data which is vital to develop strategies for site selection and to engineer the chosen locations to prevent leakage. In addition, leaking CO2 in a natural system can be studied to assess risk and the potential impact of a near-surface leak, and to test equipment, approaches, and techniques for leakage monitoring. One particularly large natural analogue study was the EC-funded NASCENT project, which examined and characterized various sites throughout Europe. One of these sites, located within the Latera cadera of central Italy, was of particular interest, and thus it subsequently became an official ‘leaking test site’ for CO2GeoNet (an EC-funded Network of Excellence on geological CO2 storage). Over the last number of years various partners involved in CO2GeoNethave visited the Latera site to test a wide range of study techniques, resulting in a unique database related to monitoring techniques and the modes and effects of CO2 leakage. The present paper gives a short overview of some of this work.