Development of geoelectrical monitoring of calcite dissolution on microfluidic chips

Ensuring sustainable strategies to manage water resources in karst reservoirs requires a better understanding of the mechanisms responsible for conduits' formation in the rock matrix, as well as the development of detection methods. Geoelectrical methods, among the various geophysical tools, have already proven their ability to monitor the hydrological and biogeochemical processes of the critical zone in a non-intrusive and low-cost manner. However, the geoelectrical signal interpretation is often approximate, as it is based on superposed microscopic source mechanisms (e.g., ionic concentration gradients, surface charge, fluid-mineral interfaces, pore-clogging). In this work, we propose a laboratory study of calcite dissolution with microscale geoelectrical monitoring on microfluidic chips. This approach allows working in well-controlled conditions, with real-time monitoring by high-speed microscopy. This work, coupled with pore network numerical simulations, will allow a better understanding of the geoelectric signature to improve its interpretation on larger scales.