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AbstractW/O emulsification in the J-7 reservoir has been regarded as the main reason for enhancing oil recovery. Therefore, in this article, the chemical structures of SARA fractions of JD-1 crude oil were obtained through characterization experiments, and the effect of the influence of SARA fractions on the W/O emulsification and the oil recovery by using emulsification experiments, interfacial experiments, emulsification experiments, and water flooding experiments. Results showed from emulsification experiments that the emulsification degree of the simulated oil containing asphaltenes was higher than other simulated oils. All emulsions of SARA fractions after emulsifying were W/O emulsions, but compared with other components, the performance of emulsions of asphaltenes was the best. The viscosity of emulsions reached 8.16–18.38 times that of simulated oil, the average size of was only 0.68 μm, and the stability was also very good. From interface tension and expansion modulus experiments, it can be seen that after adding asphaltenes, the decrease degree of interface tension and the increased degree of expansion modulus were the most. The result of molecules dynamic simulations showed that the adsorption force on the oil-water interface of asphaltenes was greater than other components. The water flooding experiments found the recovery of the simulated oil containing asphaltenes reached 43.81%, which was higher than other simulated oil, indicating that the easier W/O emulsification was formed, the recovery rate was higher. [ABSTRACT FROM AUTHOR]

The emulsification flooding is an effective method for enhance oil recovery. In this work, an amphiphilic nano titanium dioxide (ANTD) was prepared by the chemical reaction of nano titanium dioxide (NTD) with the titanate coupling agent. The contact angle experiments shown that the contact angle of NTD changed from 11.6° to 110.6°after modification, which became more lipophilic. The dispersion testing shown that Span85 was the best dispersant for ANTD. The nanofluid was configured by using 0.05 g of ANTD and 100 ml of 0.05 % Span85, which was tested by the emulsification experiment, the interface tension experiment and the dilatation rheological experiment. The result shown that the nanofluid can be emulsified to form the W/O emulsion with the crude oil, the average emulsion particle size was 1.96 µm, and the nanofluid could reduce the oil-water interface tension and improve the strength of the interface film. The wettability alteration experiment shown that the nanofluid can change the core from oil-wet to water-wet. The flow displacement experiment demonstrated that the oil recovery rate increased by 26.4 % after the nanofluid flooding. Finally, the Nuclear Magnetic Resonance experiment shown that the nanofluid could reduce the oil-water mobility rate, and expand the swept volume, thus enhancing oil recovery. [Display omitted] • An amphiphilic nano titanium dioxide (ANTD) was prepared by using nano titanium dioxide (NTD) and titanate coupling agent (TC-2). • The nanofluid was configured by using 0.05 g of ANTD and 100 ml of 0.05 % Span85. • The nanofluid can be emulsified to form the W/O emulsion with crude oil. • The nanofluid can reduce interfacial tension, improve expansion modulus, and change wettability. • The nanofluid can enhance oil recovery by reducing oil-water mobility ratio and increasing sweep volume. [ABSTRACT FROM AUTHOR]

More extensive attention has been directed toward amphiphilic nanomaterials in the field of chemical enhanced oil recovery owing to they have the same excellent properties as surfactants. In this work, an amphiphilic nano calcium carbonate(ANCC) was prepared by chemical one-pot synthesis of NCC and alkyl acid. ANCC had a lipophilic property, which can make the oil and water were completely emulsified at the concentration of 500 ppm to form W/O emulsion with a particle size of 0.2–2.6 µm. ANCC had best dispersion effect at the solution of 0.1% Tween80. In the oil-water phase, ANCC can be adsorbed on the oil-water interface to reduce interface tension, and increase interface strength, and improve emulsion stability. The lipophilic slide can be changed from lipophilic to hydrophilic when immersed in the nanofluid. Using TW-ANCC (0.1% of Tween80 +500 ppm of ANCC) as the oil displacement fluid, which improved oil recovery by 23.3% in the single core displacement experiment and by 36.9% in the flat panel visualization experiment with comparing primary water flooding. The oil displacement mechanism of TW-ANCC was obtained by the etched glass micromodel experiment and the nuclear magnetic resonance experiment, the result shown that TW-ANCC can enhance oil recovery by reducing interface tension, changing rock wettability, reducing flow in high permeability zone, and expanding sweep volume in low permeability zones. [Display omitted] [ABSTRACT FROM AUTHOR]

More extensive attention has been directed toward amphiphilic nanomaterials in the field of chemical enhanced oil recovery owing to they have the same excellent properties as surfactants. In this work, an amphiphilic nano calcium carbonate(ANCC) was prepared by chemical one-pot synthesis of NCC and alkyl acid. ANCC had a lipophilic property, which can make the oil and water were completely emulsified at the concentration of 500 ppm to form W/O emulsion with a particle size of 0.2–2.6 µm. ANCC had best dispersion effect at the solution of 0.1% Tween80. In the oil-water phase, ANCC can be adsorbed on the oil-water interface to reduce interface tension, and increase interface strength, and improve emulsion stability. The lipophilic slide can be changed from lipophilic to hydrophilic when immersed in the nanofluid. Using TW-ANCC (0.1% of Tween80 +500 ppm of ANCC) as the oil displacement fluid, which improved oil recovery by 23.3% in the single core displacement experiment and by 36.9% in the flat panel visualization experiment with comparing primary water flooding. The oil displacement mechanism of TW-ANCC was obtained by the etched glass micromodel experiment and the nuclear magnetic resonance experiment, the result shown that TW-ANCC can enhance oil recovery by reducing interface tension, changing rock wettability, reducing flow in high permeability zone, and expanding sweep volume in low permeability zones. [Display omitted] [ABSTRACT FROM AUTHOR]