Uncertainty Quantification and Assessment of CO2 Leakage in Groundwater Aquifers
Abstract
Complexity of subsurface aquifers and the geochemical reactions that control drinking water compositions complicate our ability to estimate the impact of leaking CO2 on groundwater quality. We combined lithologic field data from the High Plains Aquifer, numerical simulations, and uncertainty quantification analysis to assess the role of aquifer heterogeneity and physical transport on the extent of CO2 impacted plume over a 100-year period. The High Plains aquifer is a major aquifer over much of the central United States where CO2 may be sequestered in depleted oil and gas reservoirs or deep saline formations. Input parameters considered included, aquifer heterogeneity, permeability, porosity, regional groundwater flow, CO2 and TDS leakage rates over time, and the number of leakage source points. Sensitivity analysis suggest that variations in sand and clay permeability, correlation lengths, van Genuchten parameters, and CO2 leakage rate have the greatest impact on impacted volume or maximum distance from the leak source. A key finding is that relative sensitivity of the parameters changes over the 100-year period. Reduced order models developed from regression of the numerical simulations show that volume of the CO2-impacted aquifer increases over time with 2 order of magnitude variance.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFMGC42A..01C
- Keywords:
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- 1630 GLOBAL CHANGE / Impacts of global change;
- 1655 GLOBAL CHANGE / Water cycles;
- 1805 HYDROLOGY / Computational hydrology;
- 1831 HYDROLOGY / Groundwater quality