Chemical Force Microscopy Study on the Interactions of COOH Functional Groups with Kaolinite Surfaces: Implications for Enhanced Oil Recovery

Santha, Nipada; Cubillas, Pablo; Saw, Adrian; Brooksbank, Harry; Greenwell, Hugh Christopher

Abstract

Clay–oil interactions play a critical role in determining the wettability of sandstone oil reservoirs, which, in turn, governs the effectiveness of enhanced oil recovery methods. In this study, we have measured the adhesion between –COOH functional groups and the siloxane and aluminol faces of kaolinite clay minerals by means of chemical force microscopy as a function of pH, salinity (from 0.001 M to 1 M) and cation identity (Na+ vs. Ca2+). Results from measurements on the siloxane face show that Ca2+ displays a reverse low-salinity effect (adhesion decreasing at higher concentrations) at pH 5.5, and a low salinity effect at pH 8. At a constant Ca2+ concentration of 0.001 M, however, an increase in pH leads to larger adhesion. In contrast, a variation in the Na+ concentration showed less effect in varying the adhesion of –COOH groups to the siloxane face. Measurements on the aluminol face showed a reverse low-salinity effect at pH 5.5 in the presence of Ca2+, whereas an increase in pH with constant ion concentration resulted in a decrease in adhesion for both Ca2+ and Na+. Results are explained by looking at the kaolinite’s surface complexation and the protonation state of the functional group, and highlight a more important role of the multicomponent ion exchange mechanism in controlling adhesion than the double layer expansion mechanism

Citation

Santha, N., Cubillas, P., Saw, A., Brooksbank, H., & Greenwell, H. C. (2017). Chemical Force Microscopy Study on the Interactions of COOH Functional Groups with Kaolinite Surfaces: Implications for Enhanced Oil Recovery. Minerals, 7(12), Article 250. https://doi.org/10.3390/min7120250

• Journal Article Type: Article
• Acceptance Date: Dec 12, 2017
• Online Publication Date: Dec 19, 2017
• Publication Date: Dec 19, 2017
• Deposit Date: Jan 11, 2018
• Publicly Available Date: Jan 12, 2018
• Journal: Minerals
• Electronic ISSN: 2075-163X
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 12
• Article Number: 250
• DOI: https://doi.org/10.3390/min7120250
• Public URL: https://durham-repository.worktribe.com/output/1368697