A Hierarchic Approach for the Characterization of CO2 Permeable Pathways Using Geophysical and Geochemical Methods

Before large-scale underground CO2 storage can take place, it will be necessary to demonstrate that the processes are well understood, risks to the environment and population are low, and environmental disturbances are negligible. One of the main research questions is to understand the transport processes of CO2 from the reservoir through the earth’s crust to the surface. The locations of degassing areas are linked to faults acting as preferential pathways for the fluids. An important issue for the acceptance of the CO2 storage in geological formations is the availability of methods for the detection and monitoring of potential CO2 degassing. For an efficient and fast as well as cost effective assessment of different types of potential CO2 degassing different methods and technologies from chemistry, hydrogeology, geophysics and biology should be combined. The here presented study was carried out with the purpose to develop a sophisticated approach to investigate and to observe potential CO2 emanations in large areas with high resolution. For the secure monitoring of future geological CO2 storage sites an adapted concept for the investigations is crucially needed. The recent results obtained at natural CO2 degassing areas represent the successful application of the underlying basic hierarchical concept.