Hydrochemical and Isotopic Characteristics of CO2-rich Groundwater in the Gyeongsang Sedimentary Basin, South Korea: A Natural Analogue Study on the Potential Leakage of Geologically-stored CO2

Hyun Kwon Do, Kyoung Ho Kim, Seong Taek Yun

Research output: Contribution to journalConference articlepeer-review

3 Citations (Scopus)


The potential of geologic carbon storage has been considered in the Gyeongsang sedimentary basin (GSB) at the southeastern part of South Korea. In order to understand the long-term behaviors of geologically-stored CO2, hydrochemical and multi-isotopic data (δ18O-δD of water and δ13C of dissolved inorganic carbon) of groundwater samples were collected from naturally seeping CO2-rich springs and ambient shallow groundwater wells in the GSB. The collected samples were classified into three hydrochemical groups: 1) dilute and acidic, CO2-rich springs, 2) high TDS, CO2-rich springs, and 3) CO2-poor groundwater. CO2-rich springs (i.e., Groups 1 and 2) were differentiated from Group 3 by their high carbon isotope values and partial pressure of CO2, suggesting that the CO2 in Groups 1 and 2 originates from a deep-seated (magmatic) source. Compared to the CO2-rich springs of Group 1, major cations and HCO3-, together with Fe, Mn and Sr, are enriched in CO2-rich springs of Group 2 and these constituents are highly correlated with TDS. This indicates that, during the ascent of CO2-rich fluids via fractures, CO2-rich springs of Group 2 experienced substantial CO2-water-rock interactions, possibly through longer or restricted pathways, whereas CO2-rich springs of Group 1 acquired the chemistry through lower degrees of water-rock interaction via the rapid ascent through more permeable pathways. The results of principal component analysis (PCA) with compositional data demonstrated that pH can be used as a prior monitoring parameter to detect the direct leakage of CO2 as represented by Group 1. In addition, the changes of ionic composition can be used as a supplementary tool to monitor the indirect leakage of CO2 accompanying a substantial CO2-water-rock interaction.

Original languageEnglish
Pages (from-to)3805-3811
Number of pages7
JournalEnergy Procedia
Publication statusPublished - 2017
Event13th International Conference on Greenhouse Gas Control Technologies, GHGT 2016 - Lausanne, Switzerland
Duration: 2016 Nov 142016 Nov 18


  • CO-rich springs
  • Principal Component Analysis
  • geochemical monitoring
  • natural analogue of carbon storage

ASJC Scopus subject areas

  • Energy(all)


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