Subterranean environments are porous environments through which water flows from the surface, but also horizontally. It transports dissolved chemical species. The region of these underground environments closest to the ground (a few metres to a few dozen metres) is unsaturated: the cavities of the environment are partially filled with water and partially filled with air, part of which is in contact with atmospheric air.
The transport of chemical species by water in these unsaturated environments, and the mixing of the water that transports them with that already present, plays an important role in environmental processes. It affects soils, groundwater quality and can impact on underground carbon dioxide storage operations to reduce atmospheric carbon dioxide levels.
However, the impact of this structural heterogeneity on the movement and distribution of mixtures of dissolved chemical species, as well as on the chemical reactions that may result from their contact with other chemical species already present, has not yet been elucidated for unsaturated media.
Thus, the "UnsatPorMix" project "Impact de l'Hétérogénéité Structurale sur le Transport et le Mélange d'Espèces Chimiques Dissoutes en Milieux Poreux" (Impact of Structural Heterogeneity on the Transport and Mixing of Dissolved Chemical Species in Porous Environments) aims to understand this impact, which requires a direct measurement of the processes at the scale of the cavities.
The approach envisaged combines the development of experiments in micromodels and numerical simulations reproducing the porous geometries and the processes studied "in silico". The micromodels used are transparent synthetic porous media that model the studied subsurface environments.
The experiments aim to determine the physical and chemical ingredients to be included in the numerical simulation. The latter will allow the study of a large number of different geometries. Thus, "UnsatPorMix" will be able to quantitatively determine the link between the geometric properties of the medium (in particular the nature of its heterogeneity), the proportion of air in the cavities, but also the transport, mixing and reaction processes of the dissolved chemical species.
The project will give the winner of the MSCA "Marie Curie Sklodowska Action" grant, Oshri Borgman, the opportunity to acquire a set of experimental and modelling skills that will be useful in establishing himself as a researcher or teacher-researcher in the field of transfer in unsaturated porous media
European project UnsatPorMix - Marie S. Action Curie Action
Financing : European Commission HORIZON 2020 Programme
Institution: Université de Rennes 1
Beneficiary: Oshri BORGMAN
Name of the Scientific Director: Yves MEHEUST
Laboratory / UMR: GEOSCIENCES RENNES UMR CNRS 6118
Project duration: From 01/09/2019 to 31/08/2021 (2 years)