Interfacial Properties of Water–Crude Oil Systems Using the Oscillating Pendant Drop. Correlations to Asphaltene Solubility by Near Infrared Spectroscopy

Stability of water/crude oil emulsions based on interfacial dilatational rheology

“…This result contrasts with those reported by many authors [6,7,[16][17][18][19]27] that demonstrated that the absence of asphaltene or a high resin/asphaltene ratio in a crude oil generally reduces drastically the emulsion stability. However, McLean and Kilpatrick [19] observed that some types of resins demonstrated an ability to stabilize w/o emulsions although these resin-stabilized emulsions were less stable than those prepared with asphaltenes.…”

“…The rheological properties of these interfaces have been found to be strongly dependent on the nature of solvent used for dilution, the oil concentration, the asphaltene and resin concentrations, the resin to asphaltene ratio, and so on [16][17][18]. Nevertheless, stable w/o emulsions have been generally found to exhibit high interfacial viscosity and/or elasticity modulus.…”

“…As the stability of w/o emulsions appeared clearly related to the presence of an interfacial network surrounding the water droplets [10,11], many rheological studies of water/asphaltedoil interfaces have been made to clarify the mechanisms involved [12][13][14][15][16][17]. The rheological properties of these interfaces have been found to be strongly dependent on the nature of solvent used for dilution, the oil concentration, the asphaltene and resin concentrations, the resin to asphaltene ratio, and so on [16][17][18].…”

The Role of Asphaltenes in Stabilizing Water-in-Crude Oil Emulsions

“…Similar results as shown above have been found for other crude oils, and demonstrate that measuring interfacial rheological properties of crude oil systems is highly dependent both on the oil concentration and what solvent is used for dilution. 4 The effect of high-interfacial activity in aliphatic solvents is quickly opposed by asphaltene aggregation when increasing the oil concentration. When comparing the interfacial rheological properties of different crude oils, both these effects have to be taken into consideration.…”

“…The left-hand side of Figure 21.15 shows the measured elasticity as a function of crude oil concentration and solvent composition for a diluted crude oil. 4 The sample was diluted in heptane/toluene solutions containing 0, 50, 95, and 100 vol% heptane (heptol(0)-heptol(100)) at concentrations of 0.002, 0.01, and 0.02 mL oil/mL solvent. In addition all the solutions were characterized by NIR spectroscopy, and on the right-hand side of the figure are shown the corresponding optical density at 1600 nm from the NIR spectra of the crude oil solutions.…”