Formation and stability of W/O emulsions in presence of asphaltene at reservoir thermodynamic conditions

Development of Water-in-Oil Emulsions as Delivery Vehicles and Testing with a Natural Antimicrobial Extract

“…The main challenge in emulsion technology is their stability, once they are thermodynamically unstable systems [10][11][12]. However, the kinetic transition to the water/oil separated phases can be so slow that the emulsion may be considered metastable [13].…”

Demulsification Treatment of Spent Metalworking Fluids by Metal Cations: The Synergistic Effect and Efficiency Evaluation

“…was carried out, the demulsification of those emulsified oil pollutants played a key role throughout the L-MWFs' treatment. Currently, common demulsification methods mainly included chemical (such as the addition of organic demulsification [12,13], acidified demulsification [14] and inorganic demulsification [15]), physical (such as thermal demulsification [16], ultrasonic demulsification [17] and membrane demulsification [18]) and the combined physical-chemical method, among which the chemical demulsification methods are the main technology for demulsification at present by virtue of their low investment cost and excellent efficiency. Specifically, (i) organic demulsification means that the water and oil are layered through adding specific organic demulsifiers (such as polymeric flocculant and surfactant [12]), however, the screening process of the demulsifier was so tedious that the efficiency was difficult to remain stable against the complex emulsified oil mixtures such as L-MWFs; (ii) the acidified demulsification [14] was accomplished by the neutralization of the diffused anionic emulsifier by protons discharged under acid conditions; nevertheless, the demulsification efficiency was relatively poor, and the pH environment was seriously corrosive to the equipment in extreme cases; (iii) the inorganic demulsification mainly carried out by the electrolytes (such as ferrous chloride, calcium chloride, polymeric aluminium and polyferric chloride, etc., [19] as well as the reinforced, oriented, additional and inorganic flocculant), similarly to the organic demulsification, had a functional metal ion screening process that was complex, which led to less reports on the inorganic demulsification screening for L-MWFs.…”

Injection of emulsions into cores packed with Ottawa sand and Berea sandstone as a method for enhanced oil recovery

“…Liu et al, 2019;Nazar et al, 2011;F. Yu et al, 2019;Zhou et al, 2020), which can be stabilized by the presence of asphaltenes, waxes, resins and naphthenic acids (Ahmadi et al, 2019;Ismail et al, 2020;Lee & Babadagli, 2020;Pang et al, 2019). When the emulsifier concentration is 0.4 or 0.5 %, pore-throat-scale emulsions with viscosity between 40-70 mPa•s can be formed and with the increase of emulsifier concentration, the storage modulus of emulsion increases related to the loss modulus, enhancing the viscoelasticity of formed emulsions compared to emulsions formed with 0.3 % or less surfactant (Zhou et al, 2017).…”

“…The type of preformed emulsion, oil/water fraction in the emulsion and the formation of dispersed droplets with desired size allow the monitoring of the additional oil displacement mechanism, which is complex (Ismail et al, 2020;F. Yu et al, 2019), based on the blocking of the porous medium and related to the capillary number, which is defined as the ratio of viscous to capillary forces, is more effective at low capillary numbers less than 10-4.…”