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Abstract
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Concerning the potential positive role of water in oil emulsification in enhancing oil recovery, the current research builds on finding reasons responsible for the considerable water in oil emulsification observed in the produced fluid during carbonate sand pack floodings in the previous works. Allowing a systematic comparison, the results on floodings of three Fe3O4-based nanocomposites were selected from previous studies. The XRD and FESEM of nanocomposites, zeta potentials, stability of synthetic emulsions, IFT, bulk and interfacial oil/water viscosities, and asphaltene adsorption in the presence of nanocomposites were analyzed.
The XRD and FESEM results showed a successful synthesis for all nanocomposites. Zeta potential measurements showed values far above −40 mV, which confirm a good stability for all nanocomposites in the base fluid. In terms of emulsion stability, microscopic images showed that all synthesized nanocomposites had better performance in stabilizing synthetic emulsion droplets as compared to Fe3O4 NPs. IFT measurements indicated an 18–21 mN/m decrease with the addition of nanocomposites to the seawater. The bulk viscosity measurements indicated that Fe3O4/Chitosan nanocomposites present in the aqueous phase increase the water/oil (30/70 vol%) emulsion viscosity up to 334 cp. The interfacial viscosity measurements also showed a reduced oil/water interfacial viscosity by the addition of nanocomposites to the aqueous phase, which is probably due to the increased presence of asphaltene molecules at the interface. In the end, the absorbed asphaltene particles by nanocomposites were measured using batch adsorption experiments and fitted to the BET adsorption isotherm. The results showed that by deploying at the interface, Fe3O4-based nanocomposites are highly capable of asphaltene adsorption, which can stabilize the water in oil emulsions.
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