|dc.description.abstract||In-situ oil-in-water emulsion generation, using modified silica hydrophilic nanoparticles as emulsifier, has been proposed as an enhanced oil recovery process. The nanoparticles are injected as an aqueous dispersion; its hydrophilic character allows emulsifying the immobile heavy oil, and transports it out of the reservoir as a low viscosity fluid. Generating the emulsions in the reservoir was suggested because it offers numerous advantages. The first advantage is low injectivity pressures due to the low dispersion viscosity. Also, the size of nanoparticles (5 nm) yields a better emulsion stability. Furthermore, complex injection facilities are not required, which reduces operational costs.
In this research, 12 nanoparticle dispersions were created using nanoparticle concentrations of 0.5, 2.0 and 5.0 wt%, deionized water or brine made with 0.5 wt% of Sodium Chloride. These dispersions were tested to investigate their ability to generate oil-in-water emulsions. Emulsion generation experiments included interfacial tension measurements between heavy oil and nanoparticle dispersions, microscopy analysis to determine the amount of emulsion generated, and emulsion viscosity measurements. Results obtained from these experiments indicated that the nanoparticles lead to a reduction of the interfacial tension of the heavy oil and the dispersion. In addition, the presence of Sodium Chloride in the dispersion reduced still more of that interfacial tension, generating the largest amount of emulsions.
Six core flooding experiments were conducted to study the effect of the nanoparticle dispersion flooding on the final recovery under different settings. Two types of core plugs with permeabilities of 150 mD and 2,300 mD, and two heavy oils with viscosities of 600 cP and 3500 cP were combined to establish the original experiment conditions. Tertiary heavy oil recoveries ranged from 20% to 64 % of OOIP were obtained. The results throughout these experiments suggest that if the reservoir conditions (e.g. permeability, porosity and oil viscosity) are adequate, the nanoparticle dispersion flooding may be a reliable alternative to the thermal recovery processes.||