The effect of surfactants (alkyl olefin sulfonate and cetyltrimethylammonium bromide) on the chemical reactions in CO2-brine-clay mineral systems (montmorillonite and sepiolite) was studied under subcritical to supercritical CO2 conditions (10–150 bar at 45 °C). Compared to the CO2-brine-clay mineral system without surfactants, the introduction of surfactants increased CO2 solubility. Dissolution of Si from montmorillonite and sepiolite increased significantly on addition of the surfactants, which was unlike the results from the system without surfactants. The structural changes of the clay minerals after reaction in the CO2-brine medium with surfactants were analyzed using various techniques. The pore structure of montmorillonite and sepiolite was changed after reaction in the systems with surfactants, and the adsorption of surfactants on the clay minerals led to more significant change of pore structure. The added surfactants conserved the micro-crystallinity of montmorillonite, which otherwise collapsed considerably after dissolution reactions conducted without surfactants. The experimental and calculated results indicated that the structural changes and dissolution of clay minerals could be accelerated by adding surfactants during CO2 geological sequestration combined with enhanced oil and gas recovery (CO2 foam-EOR and EGR).
Bibliographical noteFunding Information:
This work was supported by the Korea Institute of Energy Technology Evaluation and Planning ( 20172010202070 ) funded by the Ministry of Trade, Industry & Energy (MOTIE, South Korea).
© 2019 Elsevier B.V.
All Science Journal Classification (ASJC) codes
- Environmental Chemistry
- Chemical Engineering(all)
- Industrial and Manufacturing Engineering