The study on the properties of the newly extended Gemini surfactants and their application potentials in the petroleum industry

In this study, the newly extended Gemini surfactants (EGSs) were studied as potential candidates in the petroleum industry applications. The performances of EGSs with respect to variant spacer lengths were studied through surface tension, conductivity, dynamic light scattering (DLS), interfacial tension, rheological behavior, field emission electron microscopy (FESEM), core flooding, and corrosion inhibition measurements. The surface pressure (πCMC), surface efficiency (pC20), critical micelle concentration (CMC), maximum surface excess concentration (Γmax), minimum area per molecule of surfactant at the air-water interface (Amin), average the degree of counterion binding to micelle (β), Gibb's free energy of micellization (ΔGmic), and Gibb's free energy of adsorption (ΔGads) of the EGSs were determined from surface tension and conductivity data. The results showed that the EGSs exhibited more surface activity properties, low CMCs, and spontaneously adsorbed at the air-water interface and micellized in the bulk aqueous phase. The surfactants reduced the oil-water interfacial tension (IFT) to ultralow values (10−3 mN/m) at low concentration, and it decreased substantively to very ultralow values (10−4 mN/m) due to the addition of inorganic salts. Also, they exhibited fascinating viscosifying effect and viscoelastic behavior at the experimental temperatures (30 °C–60 °C). The rheological behaviors were influenced by the formation of entangled micelles in aqueous solutions. Furthermore, through core flooding, EGS1 increased oil recovery by 12.30% which is an interesting incremental recovery. Besides, the EGSs surfactants showed high anticorrosion efficacy on A3 carbon steel in 1 M HCl aqueous solution and the inhibitive action mechanism was revealed to be by creating a protective film on the carbon steel surface through physisorption.