GCCC Feature - Dedolomitization, CO2 and Freshwater Aquifers

Katherine D. Romanak
Rebecca C. Smyth
Changbing Yang
Susan D. Hovorka
Jiemin Lu

 

February 2011 -- Our examination of groundwater geochemistry at a site where CO2 has been injected for decades shows that understanding water-rock interaction is critical to correct interpretations regarding CO2 storage evaluation. Whereas it is currently widely accepted that input of CO2 into an aquifer system will result in calcite dissolution leading to increases in HCO3 - and decreases in pH, we have found that these generalizations may not hold true in all hydrogeologic settings. For example, our geochemical models show that the process of dedolomitization will mimic the effects of calcite dissolution by increasing Ca2+ and decreasing pH, but this reaction is in response to input of calcium ions, not CO2.

 

Role of Dedolomitization in the Detection of Anthropogenic CO2
in Freshwater Aquifers

GCCC Digital Publication Series #10-02

Katherine D. Romanak
Rebecca C. Smyth
Changbing Yang
Susan D. Hovorka
Jiemin Lu

Keywords:
CO2-EOR (Enhanced oil recovery); Field study-SACROC-Scurry Co-TX; Modeling-Geochemical; Monitoring; Monitoring-groundwater-USDW; Rock-CO2-water interaction; Rock-water-CO2 reaction

Cited as:
Romanak, K. D., Smyth, R. C., Yang, C., Hovorka, S. D., and Lu, J., Role of dedolomitization in the detection of anthropogenic CO2 in freshwater aquifers: paper presented at the Water Rock Interaction 13 Conference, 16-20 August, 2010, Guanajuato, México. GCCC Digital Publication Series #10-02, pp. 1-4.

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