Hydro-geochemical impact of CO2 leakage from geological storage on shallow potable aquifers: A field scale pilot experiment

Aaron G. Cahill, Rasmus Jakobsen

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

A shallow CO2 injection experiment was conducted in an unconfined, unconsolidated siliclastic aquifer in western Denmark. The aims were to test injection and sampling systems, confirm the conceptual hydrogeological site model and determine the aquifers potential geochemical response to a larger scale, sustained CO2 injection in order to finalize design of the main release experiment. Food grade CO2 (45kg in 48h) was injected at 10m depth into glacial sand and water chemistry subsequently monitored. Results indicate the injection system effectively delivered CO2 gas into the glacial sand layer where it dissolved and moved with advective flow. Dissolved CO2 was not detected in the aeolian sand (0-5m depth) indicating prevention of migration due to permeability heterogeneities. Dissolved CO2 in the glacial sand (5-10m depth) created a plume of depressed pH (5.6-4.7), elevated EC (166-304μS/cm) and concurrent increases in dissolved ion concentrations. EC was the most effective indicator for presence of dissolved CO2. Ionic concentration changes were generally slight with increases in Al, Ba, K, Na, Mg, Si, Sr and Zn forming the major changes. Water quality was not significantly affected and risks from small scale, short duration CO2 contamination appear minimal for this geological setting.

Original languageEnglish
Pages (from-to)678-688
Number of pages11
JournalInternational Journal of Greenhouse Gas Control
Volume19
DOIs
Publication statusPublished - 1 Nov 2013

Keywords

  • Carbon capture and geological storage
  • Carbon dioxide
  • Groundwater chemistry
  • Leakage
  • Trace metals

ASJC Scopus subject areas

  • Pollution
  • Energy(all)
  • Industrial and Manufacturing Engineering
  • Management, Monitoring, Policy and Law

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