Although wettability alteration has been shown to be the main control mechanism of Low Salinity and Smart Water (LS-SmW) injection, understanding of the phenomena resulting in wettability changes still remains incomplete. Thus, direct measurement of wettability through contact angle measurement at ambient and elevated temperatures (28°C and 90°C) during LS-SmW injection to identify trends in wettability alteration was carried out. Zeta potential measurement was applied as an indirect technique for wettability assessment in rock/brine and oil/brine interfaces in order to validate the contact angle measurements. The results provided a new understanding to the effect of temperature and different ions on the wettability state of dolomite particles during an enhanced oil recovery process. Observations showed that increasing temperature from 28°C to 90°C reduced the contact angle of oil droplets from 140 to 41 degrees when Seawater (SW) was injected. Additionally, changing crude oil from crude-A (low asphaltene content) to crude-B (high asphaltene content) contributed to more negative surface charges at the oil/brine interface. The results suggested that the sulfate ion (SO2-4 ) was the most effective ion for altering dolomite surface properties, leading to less oil wetness. Wettability alteration at ambient and elevated temperatures during LS-SmW injection could be explained by Electrical Double Layer (EDL) theory.
ASJC Scopus subject areas
- Chemical Engineering(all)
- Fuel Technology
- Energy Engineering and Power Technology