Underground CO2 geological storage in deep saline aquifers represents a mediation solution for reducing the anthropogenic CO2 emissions. Consequently, this kind of storage required adequate scientific knowledge to evaluate injection scenarios, estimate reservoir capacity and asses leakage risks. In this context, we have developed and used high pressure / high temperature microfluidic tools to investigate the different mechanisms associated with CO2 geological storage in deep saline aquifers. The silicon-Pyrex 2D porous networks can replicate the reservoir p,T conditions (25 < T < 50°C, 50 < p < 10 MPa), geological and topological properties.
This talk will first highlight the strategy to access to global characteristics of our porous media such as porosity and permeability, which are later compared to numerical modelling results. The presentation will then focus on the use of GLoCs to investigate each trapping mechanisms at pore scale. The direct optical visualization and image treatments allow us to follow the evolution of the CO2/brine phase distribution of the injected CO2 within the reservoir, including displacement mechanisms and pore saturation levels. Finally, we will present some ongoing work aiming at coupling GLoCs to spectroscopy and optical characterization to get information about dissolution and mineralization trapping such as Raman spectroscopy or the integration of optic fibers to our HP/HT microsystems. Beyond CO2 geological storage investigations, the GLoCs could also find wider applications in geological-related studies such as Enhanced Oil Recovery (EOR), shale gas recovery or geothermal energy.