Effect of Composition and Interfacial Tension on the Rheology and Morphology of Heavy Oil-In-Water Emulsions

Abstract

Rheological and morphological properties of heavy crude oil-in-water (O/W) emulsions have been studied. Two series of emulsions were considered: first, the surfactant type remained constant, while the continuous phase content was varied and second, the surfactant type was varied while the continuous phase content remained constant. Under stress-controlled shearing, all samples exhibit viscoplastic behavior. The rheological properties are directly related to the morphology of the emulsions which vary in size of dispersed phase droplets and their inherent structure. Adding a surfactant characterized by a high value of interfacial oil–water tension results in a decrease in the yield stress (which is a measure of the interparticulate structure strength). The same effect is attained by increasing the water content. Meanwhile, these two factors determine the viscosity which can be much lower than that of the basic heavy crude oil if the O/W type of emulsions has been created. Special attention was paid to the viscoelastic properties which have been scarcely reported. Correlations were found between the surfactant properties, composition of the emulsion, and rheological characteristics of emulsions (yield stress, apparent viscosity, and viscoelastic properties), which allows for reduction in the crude oil viscosity down to a low enough level acceptable for pipe transportation.

Breaking of Emulsions with Chemical Additives: Using Surrogate Fluids to Develop a Novel Theoretical Framework and Its Application to Water-in-Crude Oil Emulsions

“…By lowering the W/O interfacial tension of the system, the presence of Tween 20 (the demulsifier) leads to the formation of smaller droplets during emulsification (see the SI). Since at high Reynolds numbers, the mean droplet size results from a balance between the droplet interfacial and inertial stresses, R 0 scalesfor a given Reynolds numberas γ 3/5 , where γ is the W/O interfacial tension of the system, as experimentally reported . If one considers that R 0 varies with γ, according to this scaling law, it is then straightforward to establish from eq that: .…”

“…Since at high Reynolds numbers, the mean droplet size results from a balance between the droplet interfacial and inertial stresses, 18 R 0 scalesfor a given Reynolds numberas γ 3/5 , where γ is the W/O interfacial tension of the system, as experimentally reported. 19 If one considers that R 0 varies with γ, according to this scaling law, it is then straightforward to establish from eq 7 that:…”

A review on octenyl succinic anhydride modified starch‐based Pickering‐emulsion: Instabilities and ingredients interactions

“…Additionally, the oil/water interfacial tension indicates the velocity and the performance of water spreading. For example, the lower is the interfacial tension, the greater is the extent of spreading (Arinina, Zuev, Kulichikhin, & Malkin, 2020; Gaonkar, 1989). All these parameters above influence the sensorial properties of final emulsions as well as their stability.…”

Nanoemulsions: formation, stability and an account of dietary polyphenol encapsulation

“…It is achieved by altering the emulsifier nature or composition of an aqueous phase and the addition of suitable surfactants forming a thick multilamellar film that adsorbs over the droplet interface (Qadir et al ., 2016). The stability of NE also varies with the rheological behaviour of the emulsions which depends on the ratio of oil and water and the size distribution of the droplets (Arinina et al ., 2020). Pal (2000) reported that concentrated samples of NE mostly exhibit shear‐thinning behaviour and the viscosity of the NE system is determined by droplet size.…”