Présentations Colloques

Oral Presentation
Session 5.03: CO2 storage in deep saline aquifers and potential impacts on shallow aquifers
Kissinger Alexander
Assessment of brine migration along vertical pathways due to CO2 injection
Brine migration into potential drinking water aquifers due to the injection of CO2 into deep saline aquifers is perceived as a potential threat resulting from the Carbon Capture and Storage Technology (CCS). **In this work, we focus on the large scale impacts of CO2 injection into deep saline aquifers on brine migration. The methodology and the obtained results may also apply to other fields like waste water disposal, where large amounts of fluid are injected into the subsurface. **We consider a realistic (but not real) on-shore site in the North German Basin with characteristic geological features such as a fault zone, a salt wall and hydrogeological windows in the Rupelian clay. These features influence brine migration rates into shallow aquifers. In contrast to modeling on the reservoir scale, the spatial scale in this work is much larger in both vertical and lateral direction, since the regional hydrogeology is considered as well by including groundwater recharge for shallow aquifers. Additionally, variable density flow due to salt transport is considered.**At first different scenarios are simulated in order to identify the relevant parameters for brine migration within this setting. Simulations on this scale always require a compromise between the accuracy of the description of the relevant physical processes, data availability and computational resources. Therefore, we further test different model simplifications and discuss them with respect to the relevant physical processes and the expected data availability. The simplifications in the models are concerned with the role of salt-induced density differences on the flow, with injection of brine (into brine) instead of CO2 into brine, and with simplifying the geometry of the site.