Effect of asphaltene and resin on interfacial tension of acidic crude oil/ sulfate aqueous solution: Experimental study

• Natural surfactants of acidic crude oil (i.e. asphaltene and resin) are extracted.
• Interfacial tensions of natural surfactant/sulfate solution are examined.
• Different salts including Na2SO4, MgSO4, and CaSO4 are investigated.
• It is found that asphaltene has higher affinity to the surface compared to resin.

Although the capability of using sulfate anion as a wettability modiffier is well established, no systematic investigation on the effect of sulfate ions and natural surfactants in the crude oil including asphaltene and resin on the interfacial tension (IFT) of acidic crude oil (ACO)/sulfate were performed. In this regards, the fluid/fluid interactions are tested through the IFT measurements for ACO, asphaltene and resin extracted from ACO in the presence of sulfate salts including Na2SO4, MgSO4 and CaSO4 while the concentration of each salt ranges between 0 and 45000 ppm. The obtained results demonstrate that the capability of asphaltene molecules is higher for IFT reduction compared with the resin molecules which can be related to the higher affinity of asphaltene to be arranged on the surface of ACO/sulfate aqueous solutions.

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