Table 1. pH, Temperature, conductivity and hydrochemistry of samples

DOI

Carbon dioxide deep geological storage, especially in deep saline aquifers, is one of the preferred technological options to mitigate the effects of greenhouse gases emissions. Thus, in the last decade, studies characterising the behaviour of potential CO2 deep geological storage sites along with thorough safety assessments have been considered essential in order to minimise the risks associated with these sites. The study of natural analogues represents the best source of reliable information about the expected hydrogeochemical processes involved in the CO2 storage in such deep saline aquifers.In this work, a comprehensive study of the hydrogeochemical features and processes taking place at the natural analogue of the Alicún de las Torres thermal system (Betic Cordillera) has been conducted. Thus, the main water/CO2/rock interaction processes occurring at the thermal system have been identified, quantified and modelled, and a principle conclusion is that the hydrogeochemical evolution of the thermal system is controlled by a global dedolomitization process triggered by gypsum dissolution. This geochemical process generates a different geochemical environment to that which would result from the exclusive dissolution of carbonates from the deep aquifer, which is generally considered as the direct result of CO2 injection in a deep carbonate aquifer. Therefore, discounting of the dedolomitization process in any CO2 deep geological storage may lead to erroneous conclusions. This process will also influence the porosity evolution of the CO2 storage formation, which is a very relevant parameter when evaluating a reservoir for CO2 storage. The geothermometric calculation performed in this work leads to estimate that the thermal water reservoir is located between 650 and 800 m depth, which is very close to the minimum required to inject CO2 in a deep geological storage.It is clear that the proper characterisation of the features and hydrogeochemical processes taking place at a natural system analogous to a man-made deep geological storage will provide useful conceptual, semi-quantitative and even quantitative information about the processes and consequences that may occur at the artificial storage system.

Supplement to: Prado-Pérez, Antonio; Pérez del Villar, Luís (2011): Dedolomitization as an analogue process for assessing the long-term behaviour of a CO2 deep geological storage: The Alicún de las Torres thermal system (Betic Cordillera, Spain). Chemical Geology, 289(1-2), 98-113

Identifier
DOI https://doi.org/10.1594/PANGAEA.855515
Related Identifier https://doi.org/10.1016/j.chemgeo.2011.07.017
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.855515
Provenance
Creator Prado-Pérez, Antonio; Pérez del Villar, Luís
Publisher PANGAEA
Publication Year 2011
Funding Reference Seventh Framework Programme https://doi.org/10.13039/100011102 Crossref Funder ID 265847 https://cordis.europa.eu/project/id/265847 Sub-seabed CO2 Storage: Impact on Marine Ecosystems
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 298 data points
Discipline Earth System Research
Spatial Coverage (-3.120 LON, 37.500 LAT); Alicún de las Torres, southern Spain