Brine migration along vertical pathways due to CO2 injection – a simulated case study in the North German Basin with stakeholder involvement
Alexander Kissinger1, Vera Noack2, Stefan Knopf2, Wilfried Konrad3, Dirk Scheer3, and Holger Class11Department of Hydromechanics and Modelling of Hydrosystems, University Stuttgart, Pfaffenwaldring 61, 70569 Stuttgart, Germany 2Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Stilleweg 2, 30655 Hannover 3DIALOGIK, Lerchenstraße 22, 70176 Stuttgart, Germany
Received: 02 Jun 2016 – Accepted for review: 06 Jun 2016 – Discussion started: 08 Jun 2016
Abstract. Brine migration into potential drinking water aquifers due to the injection of CO2 into deep saline aquifers is one of the potential hazards associated with the Carbon Capture and Storage technology (CCS). Thus, in any site selection process, an important criterion should be the evaluation of brine migration resulting from the injection. We follow an interdisciplinary approach using participatory modeling to incorporate stakeholder opinion at an early stage in order to discuss and evaluate model conception and relevant scenarios for brine migration. The basis for this approach is a realistic (but not real) on-shore site in the North German Basin with characteristic geological features for that region. Our model fully couples flow in shallow and in deep saline aquifers including variable-density transport of salt and a realistic description of the top surface boundary conditions with groundwater recharge and rivers. We investigate different scenarios to identify relevant system components. Further, different model simplifications are compared and discussed with respect to the relevant physical processes and the expected data availability, i.e. to find a model as complex as necessary and as simple as possible. It becomes clear that the initial salt distribution plays a key role as to where noticeable concentration changes may occur. Also the boundary conditions are important for determining the amount of vertically displaced brine. Simplifications in the model setup, such as neglecting variable-density flow or simplifying the complex geometry may prove valid options given sparse data availability.
Kissinger, A., Noack, V., Knopf, S., Konrad, W., Scheer, D., and Class, H.: Brine migration along vertical pathways due to CO2 injection – a simulated case study in the North German Basin with stakeholder involvement, Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2016-281, 2016.