Factors impacting the performance of polymer-based EOR in oil reservoirs

Pickering emulsions stabilized by surfactant-modified SiO 2 nanoparticles demonstrate good stability against droplet coalescence, showing application potential for enhanced oil recovery in high-temperature and high-salinity environments. Adjusting the adsorption ratio of surfactant on the nanoparticles significantly affects the wettability of nanoparticles and therefore regulates the microstructure and properties of Pickering emulsions. In this study, a saturated monolayer adsorption occurs at a surfactant-to-nanoparticles ratio of 0.1:1.0%, where an optimal hydrophilic−hydrophobic balance is achieved. However, below or above this ratio, the SiO 2 nanoparticles become more hydrophilic with the decreasing or increasing surfactant concentration. Pickering emulsions stabilized by the intermediate wet nanoparticles exhibit the best stability and highest viscosity. Laser confocal scanning microscopy and cryo-scanning electron microscopy reveal that the SiO 2 nanoparticles can form a bridge-structure network among the droplets of these emulsions. Microfluidic experiments and sand pack experiments show that Pickering emulsions provide greater permeation resistance than conventional emulsions stabilized solely by surfactant solely. In addition, microscopic experiments show that Pickering emulsions enhance oil recovery by 20% after second waterflooding, compared to a 12% recovery rate with conventional emulsions. It is found that the Pickering emulsions with bridge-structures may be accumulated in and plug channels much larger than their droplets, which results in higher properties of conformance control.

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Immiscible invasion of granular suspension by high-viscosity liquid

Qin,

Li,

et al. 2024

Physics of Fluids

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We investigate the morphology and dynamics of the pattern of immiscible invasion by injecting a high-viscosity liquid into a granular suspension consisting of movable solid grains in a low-viscosity liquid. Laboratory experiments conducted in a Hele–Shaw cell shed light on how the frictional forces of the grains and the viscous forces of the liquids affect the instability of the liquid–liquid interface and the formation of viscous fingers. The frictional force increases with an increase in either the volume fraction or the size of the grains, leading to higher resistance to the invading pattern. Upon changing the grain shape from spherical to irregular, both the frictional force and the rotational energy of the grains increase, resulting in more numerous but narrower fingers. Increasing either the injection rate or the viscosity of the injected liquid increases the viscous pressure within the fingers, promoting the splitting of the pattern. Although the defending liquid always has a lower viscosity than the invading liquid in this study, the former's viscous force becomes non-negligible as the viscosity ratio of the invading liquid to the defending liquid decreases to near unity, which destabilizes the fluid–fluid interface and causes a transition to an asymmetric pattern.

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Factors impacting the performance of polymer-based EOR in oil reservoirs

Cited by 5 publications

References 26 publications

Study on oil-in-water emulsions stabilized by SiO2 nanoparticles for enhancing oil recovery in harsh reservoirs

Study on oil-in-water emulsions stabilized by SiO2 nanoparticles for enhancing oil recovery in harsh reservoirs

Study on the Enhanced Oil Recovery Properties of the Pickering Emulsions for Harsh Reservoirs

Immiscible invasion of granular suspension by high-viscosity liquid

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