Heterogeneity‐enhanced gas phase formation in shallow aquifers during leakage of CO2‐saturated water from geologic sequestration sites. Issue 12 (8th December 2014)

• Record Type: Journal Article
• Authors: Plampin, Michael R.; Lassen, Rune N.; Sakaki, Toshihiro; Porter, Mark L.; Pawar, Rajesh J.; Jensen, Karsten H.; Illangasekare, Tissa H.
• Is Part Of: Water resources research. Volume 50:Issue 12(2014:Dec.)
• Page Start: 9251
• Page End: 9266
• Publication Date: 2014-12-08
• Subjects: Hydrology -- Periodicals; 333.91
• DOI: 10.1002/2014WR015715
• Languages: English
• ISSNs: 0043-1397

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>A primary concern for geologic carbon storage is the potential for leakage of stored carbon dioxide (CO<sub>2</sub>) into the shallow subsurface where it could degrade the quality of groundwater and surface water. In order to predict and mitigate the potentially negative impacts of CO<sub>2</sub> leakage, it is important to understand the physical processes that CO<sub>2</sub> will undergo as it moves through naturally heterogeneous porous media formations. Previous studies have shown that heterogeneity can enhance the evolution of gas phase CO<sub>2</sub> in some cases, but the conditions under which this occurs have not yet been quantitatively defined, nor tested through laboratory experiments. This study quantitatively investigates the effects of geologic heterogeneity on the process of gas phase CO<sub>2</sub> evolution in shallow aquifers through an extensive set of experiments conducted in a column that was packed with layers of various test sands. Soil moisture sensors were utilized to observe the formation of gas phase near the porous media interfaces. Results indicate that the conditions under which heterogeneity controls gas phase evolution can be successfully predicted through analysis of simple parameters, including the dissolved CO<sub>2</sub> concentration in the flowing water, the distance between the heterogeneity and the leakage location, and some fundamental properties of the porous media. Results also show that interfaces where a less permeable material overlies a more permeable material affect gas phase evolution more significantly than interfaces with the opposite layering.</p> </abstract>