CO2 Long-term Periodic Injection Experiment (CO2LPIE) Multidisciplinary Fluid-Rock Investigations on Multiple Scales

Abstract

CO2 Long-term Periodic Injection Experiment (CO2LPIE) involves multidisciplinary research focusing on the long-term impact of fluids on the integrity of geological barriers. One prominent key feature of the experiment is the time period of interest, which will cover more than a decade. This allows for a more realistic approach to improve the necessary understanding of caprocks with regard to geological carbon storage. In addition, the expected knowledge gain in caprock behavior is also of interest for storage or extraction of other fluids, solids, or energy in the subsurface, benefitting geothermal energy, nuclear waste storage, as well as groundwater use and protection.

Another key factor of CO2LPIE lies in its strongly interwoven, mutually supporting subject areas: (i) in-situ field experiment, (ii) laboratory work, and (iii) computational modeling. In this new in-situ experiment situated in the Swiss Mont Terri underground rock laboratory, the relevant thermo-hydro-mechanical-chemical processes (THMC) are investigated by a periodic CO2 injection into the local Opalinus Clay. This claystone is of longstanding special interest for radioactive waste disposal, but furthermore, it stands as an excellent proxy for a caprock. The envisioned time frame of about 15 to 20 years of CO2-rich brine exposure of the rock along with state-of-the-art monitoring will enable the quantification and understanding of the relevant THMC processes at various time scales. On the spatial scale, the expected results will bridge the knowledge gap between natural behavior and laboratory observations. All findings will be employed in various phases as input, verification, and calibration for the numerical part with the overall goal of predicting the long-term caprock behavior.