Peculiarities of rheological behavior of highly concentrated water-in-oil emulsion: The role of droplet size, surfactant, oil and ammonium nitrate content

Abstract

An investigation was performed into the rheological behavior of highly concentrated water-in-oil emulsion (HCE). The experimental results show that HCE behaves as a shear-thinning fluid and there are two platforms in the flow curve. But, the second platform at high shear rate region can't be observed with the increase of the intensity of interaction between droplets caused by the decrease of the size of dispersed phase droplets. The recovery capacity of HCE underwent shear was affected by the size of dispersed phase droplets. Relatively strong resilience was observed when the droplet size of dispersed phase was small. However, the recovery capacity of HCE underwent oscillation was not affected by the droplet size. The nature of surfactant, oil and the AN content of dispersed phase have important effect on the rheology of HCE. The plateau zone of storage modulus goes to a higher level when the blended surfactant used as surfactant. There is optimal oil viscosity region within which the higher G' can be formed. The G′ of HCE decreases obviously, while the oil-water interfacial tension decreases. The G′ decreases with the increase of the concentration of ammonium nitrate.