CO2 Exsolution - Challenges and Opportunities in Subsurface Flow Management

This paper summarizes the results of a 4-year study regarding the implications of CO2 exsolution on geological carbon storage security and subsurface flow management, including core-flood experiments, micro-model studies, pore-scale modeling, and relative permeability calculations. When separate phase CO2 exsolves from carbonated water in sandstones, water relative permeability drops significantly. The relative permeability of exsolved CO2 is disproportionately reduced compared to drainage due to the dispersed morphology of exsolved CO2 bubbles in the pore space. Our studies suggest that CO2 exsolution provides an opportunity for mobility control in subsurface processes. The low mobility of exsolved CO2 suggests that risks of groundwater contamination due to this phenomenon are small. (C) 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/3.0/).