Natural analogues: a potential approach for developing reliable monitoring methods to understand subsurface CO2 migration processes

Autor: Gerhard Strauch, U. Sauer, K. Beyer, H. Lamert, H. Kämpf, Claudia Schütze, Peter Dietrich, Karin Bräuer, Ch. Flechsig
Rok vydání: 2012
Předmět:
Zdroj: Environmental Earth Sciences
ISSN: 1866-6299
1866-6280
DOI: 10.1007/s12665-012-1701-4
Popis: One possible way of mitigating carbon dioxide (CO2) emissions from fossil fuel combustion is using carbon dioxide capture and storage (CCS) technology. However, public perception concerning CO2 storage in the geosphere is generally negative, being particularly motivated by perceived leakage risks. Therefore, a main issue when attempting to gain public acceptance is ensuring provision of appropriate monitoring practices, aimed at providing health, safety and environmental risk assessment, so that potential risks from CO2 storage are minimized. Naturally occurring CO2 deposits provide unique natural analogues for evaluating and validating methods used for the detection and monitoring of CO2 spreading and degassing into the atmosphere. Geological and hydrological structures of the Cheb Basin (NW Bohemia, Czech Republic) represent such a natural analogue for investigating CO2 leakage and offer a perfect location at which to verify monitoring tools used for direct investigation of processes along preferential migration paths. This shallow basin dating from the Tertiary age is characterized by up to 300 m thick Neogene sediment deposits and several tectonically active faults. The objectives of this paper are to introduce the CO2 analogues concept to present the Eger Rift as a suitable location for a natural CO2 analogue site and to demonstrate to what extent such an analogue site should be used (with a case study). The case study presents the results obtained from a joint application of geoelectrical measurements in combination with soil CO2 concentration and flux determination methods, for the detection and characterization of natural CO2 releases at gas seeps (as part of a hierarchic monitoring concept). To highlight discharge-controlling structural near surface features was the initial motivation for the application of geoelectrical measurements. Soil-gas concentration and flux measurement techniques are relatively simple to employ and are valuable methods that can be used to monitor seeping CO2 along preferential pathways. Joint interpretation of both approaches yields a first insight into fluid paths and reveals that the thickness and permeability of site-specific near surface sedimentary deposits have a great influence upon the spatial distribution of the CO2 degassing pattern at surface level.
Databáze: OpenAIRE
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