A microfluidic platform for assessing reaction and transport in fractured shale media

Shales are inherently multiscale systems as their characteristic length-scales can span many orders of magnitude. Petrographic and microscopic studies have shown the existence of micro-fracture networks, furthering the hypothesis that multi-scale structure may be a critical component in controlling transport processes. Thus far, the topological and chemical complexity of shales have hindered the ability to isolate the impact that shale network topology may have on transport dynamics. In this study, we designed two micromodels with a common primary fracture network but different micro-fracture topologies and compare transport experiments under different flow regimes as quantified by the Peclet number. Based on these results, we propose an experimental roadmap to increase the system complexity in such controlled systems to account for both solute reactivity and geochemical complexity.