Hydro-mechanical-chemical processes in Opalinus Clay during CO2 injection in CL experiment

This study investigates the coupled hydro-mechanical-chemical (HMC) behavior and multiphase flow properties of Opalinus Clay in the CO₂ Long-term Periodic Injection experiment (CO₂LPIE or CL) at the Mont Terri rock laboratory. CO₂LPIE located in the CL niche of Gallery 18 is targeting primarily the sandy and carbonate facies and aims to evaluate the sealing potential of Opalinus Clay as a representative caprock under periodic injection of CO₂-rich water. The primary objectives of CO₂LPIE are to: (i) characterize the coupled HMC behavior of the rock mass at relevant spatial scales, (ii) quantify long-term CO₂-induced variations in rock properties under periodic injection, (iii) determine the in-situ CO₂ breakthrough pressure, and (iv) evaluate the THMC response of the formation over decadal timescales.