Static and dynamic adsorption of supramolecular surfactant for oil recovery in high temperature and salinity conditions

Abstract

The adsorption of a supramolecular surfactant formed by the non‐covalent interactions among sodium (E)‐dodec‐2‐ene‐1‐sulfonate, sodium 3‐hydroxydodecane‐1‐sulfonate and 3‐[(3‐dodecanoylamidopropyl)dimethylazaniumyl]‐2‐hydroxypropane‐1‐sulfonate onto limestone under static and dynamic conditions in the presence of seawater and connate water is presented. In the static test at 70°C and atmospheric pressure, the adsorption capacity of the saturated monolayer was 8.65 mg/g for seawater and 4.05 mg/g for connate water. This behavior was associated with the increase of the critical micellar concentration from 217 ppm in seawater to 672 ppm in connate water, which is related to the capacity of the supramolecular surfactant to form complexes at high salinity and hardness. The dynamic experiment was carried out at 130°C with a pressure of 16,500 kPa, a flow rate of 90 mL/h and a dose of 2000 ppm of the surfactant. An adsorption of 0.230 mg/g was found in seawater, while a value of 0.109 mg/g was obtained in connate water, consistent with the static experiment. In addition, spontaneous imbibition experiments for connate and connate water with 2000 ppm of surfactant showed an increase in the oil recovery factor from 3% to 17% in the presence of surfactant at 100°C. It was observed that the rock changed from oil‐wettable to water‐wettable, indicating that the supramolecular complex retains its capability to form the monolayer on the rock surface. In contrast to the ionic and cationic conventional surfactants, the experimental evidence indicates that the surfactant preserves its properties under the extreme conditions found in mature Mexican carbonate reservoirs.