Webinar cycle in Hydrogeology and geochemistry
HYDROGEOLOGY GROUP (Associated Unit CSIC-UPC, Barcelona)
Date: Thursday, 13 Jan 2022
Starting time: 15:00pm (Central European Time)
Duration: 1h
Guest Speaker: Iman Rahimzadeh Kivi, Post-doctoral fellow
Title: Experimental and numerical insights into the likelihood of CO₂ leakage over geological time scales
live in: https://meet.google.com/snb-qdkn-eex (free of charge)
Abstract:
Carbon capture and storage (CCS) in deep geological formations is an essential part of available pathways to reach the net-zero emission target by mid-century and mitigate the climate crisis. The efficiency of the CCS technology to permanently store CO₂ underground is tightly associated with the sealing capacity of the caprock overlying the injection formation. In this presentation, we look deeper into the likelihood and governing mechanisms of CO₂ leakage through shaly caprocks. We present results of breakthrough experiments on Opalinus Clay, widely agreed to be a representative caprock for CO₂ storage. We numerically simulate laboratory experiments to determine the breakthrough pressure of Opalinus Clay and foster an improved understanding of the hydromechanical mechanisms of CO₂ intrusion into and flow across the specimens. We propose a computationally cost-effective, yet realistic upscaling approach to assess the caprock sealing capacity over geological timescales. Our observations are consistent in that the sealing capacity is unlikely to be compromised by capillary breakthrough and viscous flow through the pore network. Potential leakage will be dominated by molecular diffusion, which is intrinsically slow and does not impose a threat to the storage efficiency over hundreds of thousands of years.