Formation and Stability of Heterogeneous Organo–Ionic Surface Layers on Geological Carbonates

Many geological processes from oil recovery to underground CO2 storage are affected by natural molecules adsorbed on rock surfaces. Yet, geochemical models tend overlook their formation and stability, let alone existence. With a suite of analytical techniques, we address this “missing-link” describe fundamental mechanisms for (i) the deposition surface-active in complex brines oils minerals (ii) desorption heterogeneous sorbents its dependence aqueous composition. First, show that organic inorganic constituents both water crude form an organo–ionic surface layer calcite. Primary modifiers revealed as nonaqueous polyaromatic with polar metal-binding functional groups solubility characteristics asphaltenes. Formed via π-stacking ionic hydrogen bonding interactions, establishes physical barrier between mineral ambient atmosphere/fluid, impacting dissolution wettability rocks. Second, investigate various under flow static conditions. chromatographic spectroscopic methods (including Raman sum-frequency generation), release material carbonate surfaces encompasses key coupled reactions: “brine-soluble” asphaltenes, leading relative interfacial enrichment bulky “brine-insoluble” nanoscale orientational changes asphaltene assemblies, ions, at brine–rock interface, (iii) reconstruction mineral. Through these reactions, “low-salinity effect” is uncovered two-stage process: initial or selective extraction “water-soluble” subsequent delamination residual “water-insoluble” asphaltenes dissolving surface. Illuminating reactions minerals, conclude passivation matter not only ubiquitous nature but also regulator chemistry, reactivity