CO2 Sequestration: Studying Caprock And Fault Sealing Integrity, The CS-D Experiment In Mont Terri

A key challenge for CO2 geological storage is the integrity of the caprock. This challenge is addressed by executing a decameter-scale experiment at the Mont Terri Underground Rock Laboratory in Switzerland, under the umbrella of ELEGANCY (Enabling a Low-Carbon Economy via Hydrogen and CCS). ELEGANCY is an European project aiming at advance sustainable geo-energy processes through studies on risk mitigation, characterization and public perception, whose achievements will benefit the fields of carbon dixode sequestration. The experiment will investigating the mechanisms and the physical parameters governing the migration of CO2-rich brine through a faults. In particular, the test seeks to understand the conditions for slip activation (seismic vs. aseismic slip) and the stability of clay faults, as well as the coupling between fault slip, pore pressure, fluid migration and possible induced “micro” seismicity. To this end, we will inject CO2-rich brine into the fault core for a period of about eight months, while monitoring its geo-mechanical response. Additional tracer and transmissivity tests will be conducted at regular time intervals to determine the fluid path evolution of the injected fluid and to infer the potential evolution of CO2 from the brine. Numerical simulation work assist the different phases of the field experiment.