Adsorption of Crude Oil Components onto Carbonate and Sandstone Outcrop Rocks and Its Effect on Wettability

Research at Stevns Klint reveals that the mineral composition of rocks significantly influences how crude oil components adsorb onto their surfaces, thereby altering wettability—a critical factor for oil recovery. The study found that pure chalk preferentially adsorbs acidic components, while sandstone favors basic ones. Silica-containing chalk showed a reduced affinity for acids due to negatively charged minerals, highlighting the complex interplay between rock mineralogy and crude oil-brine interactions. Core flooding tests with light crude oils demonstrated that adsorption of polar organic components reduces water wetness across all tested cores (pure chalk, silica-containing chalk, and sandstone), emphasizing the profound impact of mineral composition on wettability dynamics. These findings underscore the importance of considering rock mineralogy when restoring core material wettability in laboratory settings.

Puntervold, T., Mamonov, A., Piñerez Torrijos, I. D., & Strand, S. (2021). Adsorption of Crude Oil Components onto Carbonate and Sandstone Outcrop Rocks and Its Effect on Wettability. Energy & Fuels, 35(7), 5738–5747. https://doi.org/10.1021/acs.energyfuels.0c03003