Experimental investigation of dynamic interfacial tension of crude oil-different aqueous solutions

Dynamic interfacial tension (DIFT) is investigated experimentally for crude oil and several of different aqueous solutions such as alkaline, brine, polymer, and different types of surfactant solutions. A spinning drop tensiometer with high resolution color video camera was employed to measure DIFT. The aqueous solution of NaOH provides a strong effect for interfacial tension (IFT) over the concentration range of 0.1-5 wt%. It was found that 0.5-1.0 wt% NaOH is the optimum concentration range to provide the lowest IFT value of 0.09 and 0.05 mN/m, respectively. The presence of NaCl shows a strong effect on interfacial tension depending upon the NaCl concentration with an optimum concentration of 10⁴ ppm which provides low interfacial tension of 5.78 mN/m after 5 min. The presence of Alcoflood polymer reduces IFT over a short period due to its physico-chemical effect. This study shows the importance of the alkaline presence within the aqueous phase of Alcoflood polymer to make sure that the IFT is sufficiently low. Different types of surfactant materials including non-ionic surfactant of Triton, X-100, anionic surfactant of Aerosol OT, cationic surfactant of Hyamine 1622, and demulsifier of Alkan DE-316 were tested. Non-ionic surfactant of Triton X-100 provided the lowest IFT values among the tested surface active materials over the concentration range of 0.1-0.5 wt%.