Effect of biopolymer addition on the formulation and properties of an oil-in-water microemulsion

In this study stable microemulsions with very low interfacial tension (IFT) were developed. This type of microemulsion has very low viscosity (very similar to that of water). For application of these systems for solubilization and enhanced oil recovery, we studied the effect on the properties of such microemulsions of adding biopolymer to increase viscosity while maintaining IFT as low as possible. Hydroxyethylcellulose and hydrophobically modified hydroxyethylcellulose were selected; their mode of addition to the formulation is discussed. Microemulsion zones were determined by phase diagram investigation in accordance with Winsor’s classification. In addition to spontaneous formation, transparency, and stability, other properties were measured and others calculated to better define the formulated systems and to confirm the presence of microemulsions. Microemulsion droplet number and size both decrease with increasing salt concentration. Depending on emulsion size, rheological measurements confirm that both polysaccharides have a favourable effect on the viscosity of microemulsion without important modification of IFT.