Table 1
Possible mechanisms of rock wettability change by injected brine, depending on rock and crude oil polarities
| Polar Oil Components (POC) | Negatively charged rock surface (clayey rocks) | Positively charged rock surface (carbonates) |
|---|---|---|
| Acidic POC | ||
| POC–rock interaction | Cation bridging | Direct adsorption |
| Wettability modification through | Ionic force decrease: brine dilution (plus cation valence reduction) | Anion substitution ( ) OR reduced POC adsorption capacity at low ionic force |
| Basic POC | ||
| POC–rock interaction | Direct adsorption | Anion bridging |
| Wettability modification through | Cation substitution OR reduced POC adsorption capacity at low ionic force | Ionic force decrease: brine dilution (plus cation valence reduction) |