A combination of microfluidics experiments and numerical simulations for the study of mineral reactivity at the pore-scale

Abstract:

An in-depth understanding of dissolution and precipitation of minerals in porous and fractured porous media and the complex feedback on the transport of fluids is essential for various subsurface applications. In this context, we developed a novel non-destructive “lab-on-chip” approach for quantitative in situ assessments of mineralogical changes in porous media. Our experimental approach involves a microfluidic flow-through reactor of reactive homogeneous and heterogeneous (fractured) porous media coupled with high-resolution imaging. The use of confocal Raman spectroscopic techniques enables the spatio-temporal visualization of the mineral transformation at the pore-scale in two- and three-dimensions. 3D images of minerals are used to obtain the evolution of bulk parameters (e.g. porosity, permeability) due to reactions. Moreover, advanced pore-scale modelling correlates the hydrological heterogeneities to the geochemical observations in the micro-reactor, which explains the observed discrepancies between homogeneous and heterogeneous reactive media. The proposed methodology can provide high-fidelity datasets to benchmark reactive transport codes that are currently under development.