Upward migration of anthropogenic CO2 and vertical finite element mesh resolution in a layered sedimentary basin

A possible option for the greenhouse effect mitigation is the disposal of anthropogenic CO2 into deep geological formations. Reliable numerical finite element models are required to simulate correctly the basic processes which underlie and control the safe storage of CO2 of industrial origin. The large saline aquifers of the Northern Adriatic basin appear to be promising porous bodies to sequester a significant amount of CO2 produced by nearby thermoelectric plants. In the present communication the influence on the upward CO2 migration of local clay units within a permeable formation is investigated. Finite element simulations are performed to address the gas break-through in a silt/shale lens embedded in a realistic Northern Adriatic aquifer where anthropogenic CO2 is injected. The vertical mesh resolution is shown to impact quite significantly on the upward CO2 flow and emphasizes the need for a properly refined mesh to ensure reliable confinement prediction.