Modeling GaseousCO₂Flow Behavior in Layered Basalts: Dimensional Analysis and Aquifer Response

Abstract

Particular attention is paid to the risk of carbon dioxide (CO2) leakage in geologic carbon sequestration (GCS) operations, as it might lead to the failure of sequestration efforts and to the contamination of underground sources of drinking water. As carbon dioxide would eventually reach shallower formations under its gaseous state, understanding its multiphase flow behavior is essential. To this aim, a hypothetical gaseous leak of carbon dioxide resulting from a well integrity failure of the GCS system in operation at Hellisheiði (CarbFix2) is here modeled. Simulations show that migration of gaseous carbon dioxide is largely affected by formation stratigraphy, intrinsic permeability, and retention properties, whereas the initial groundwater hydraulic gradient (0.0284) has practically no effect. In two different scenarios, about 18.3 and 30.6% of the CO2 that would have been injected by the GCS system for 3 days could be potentially released again into the atmosphere due to a sustained leakage of the same duration. As the gaseous leak occurs, the aquifer experiences high pressure buildups, and the presence of a less conductive layer further magnifies these. Strikingly, the dimensional analysis showed that buoyant and viscous forces can be comparable over time within the predicted gaseous plumes, even far from the leakage source. Local pressure gradients, buoyant, viscous, and capillary forces all play an important role during leakage. Therefore, neglecting one or more of these contributions might lead to a partial prediction of gaseous CO2 flow behavior in the subsurface, giving space to incorrect interpretations and wrong operational choices.

Review on Multiscale CO2 Mineralization and Geological Storage: Mechanisms, Characterization, Modeling, Applications and Perspectives

“…(a) CO 2 saturation distribution in basalt (Reproduced with permission from ref ; Copyright 2021 Wiley); (b) 3D reaction transport modeling (Reproduced with permission from ref ; Copyright 2022 Elsevier); (c) CO 2 gas saturation distribution (Reproduced with permission from ref ; Copyright 2016 Elsevier); (d) variation in the porosity of the reservoir (Reproduced with permission from ref ; Copyright 2022 Elsevier); (e) CO 2 gas saturation and dissolved CO 2 mass fraction distribution in sandstone after 30 years of injection (Reproduced with permission from ref ; Copyright 2013 Elsevier); (f) mineral dissolution of calcite (Reproduced with permission from ref ; Copyright 2022 MDPI); (g) CO 2 distribution after 10 and 100 years of injection (Reproduced with permission from ref . Copyright 2023 Elsevier).…”

“…The migration of gaseous carbon dioxide is greatly affected by the formation, intrinsic permeability, and retention properties. D’Aniello et al simulated the flow behavior of gaseous CO 2 in stratified basalts, and the predicted profile of gaseous CO 2 saturation at 3 days is shown in Figure a. At the same time, predictive three-dimensional reaction transport modeling, as shown in Figure b, can achieve an accurate prediction of changes in the mineral content, pH, and CO 2 mass fraction .…”