Investigating the synergic effects of chemical surfactant (SDBS) and biosurfactant produced by bacterium (Enterobacter cloacae) on IFT reduction and wettability alteration during MEOR process

In the current study, a novel approach which takes into account the effectiveness of both convectional surfactants and biosurfactants was investigated. The biosurfactant produced by Enterobacter cloacae strain was utilized concomitant with conventional surfactant (sodium dodecyl benzene sulfonate (SDBS)) to evaluate its capability to reduce the SDBS adsorption on rock surface (biosurfactant acts as sacrificial agent) or synergistically enhance the effectiveness of the SDBS. In this regard, the wettability alteration and interfacial tension (IFT) measurements and calculation of spreading coefficient were performed considering two different scenarios. In the first scenario, SDBS was added to the incubated bacterial solution medium while in the second case, SDBS was added to the bacterial solution before the incubation stage. Based on the obtained results, it was revealed that the wettability altered from original oil wet towards water wet state using bacterial solution, while the addition of SDBS deteriorated this trend for both scenarios. According to IFT measurements, the first scenario was more effective than the individual solution of bacteria and SDBS as well as the second scenario. In conclusion, the measured spreading coefficient demonstrated that the bacterial solution was a more effective EOR agent in comparison to other studied cases. (C) 2018 Elsevier B.V. All rights reserved.