Molecular Dynamics-Based Simulation on Chemical Flooding Produced Emulsion Formation and Stabilization: A Critical Review

Wang, Zhihua; Xu, Yunfei; Liu, Yang; Liu, Xiaoyu; Rui, Zhenhua

doi:10.1007/s13369-020-04840-9

Cited by 34 publications

(15 citation statements)

References 64 publications

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“…To analyze the diffusion properties of wax–asphaltene molecules on the non-coated wall surface, the mean square displacement (MSD) is introduced here to reflect the deviation of the spatial position of a particle from its initial position during the MD simulation, and the MSD expression is as follows. where N is the number of diffusing molecules in the simulation system; r i ( t ) is the position of particle i at time t ; and r 0 ( t ) is the position of particle i at the initial time. A larger slope of the MSD curve indicates that the target molecule is more capable of migration and movement. , Furthermore, the MSD curve can also be converted into the diffusion coefficient D through the Stocks–Einstein formula to realize the quantitative characterization of the target molecular motion properties …”

Section: Resultsmentioning

confidence: 99%

“…The interaction energy is an important parameter to determine the strength of the interaction between two contacting materials, , and it reflects the interaction strength between the heavy component molecules and coated wall surface in this paper. The higher the absolute value of interaction energy, the stronger the bond of heavy component molecules with the coated wall surface, which also means the stronger the adsorption of heavy component molecules on the coated wall surface. where E total is the total energy of the system, kJ/mol; E Interaction is the interaction energy between heavy component molecules and non-coated and coated wall surface, kJ/mol; E non‑coated is the total energy of the non-coated wall system, kJ/mol; E coated is the total energy of the coated wall system, kJ/mol; E wax is the total energy of wax molecules, kJ/mol; E asp is the total energy of asphaltene molecules, kJ/mol.…”

Section: Resultsmentioning

confidence: 99%

“…There are several predominant methods to prevent and control the deposition of heavy components on the pipe walls, which can be achieved by mechanical, physical, and chemical means. , As the primitive approach, the mechanical methods utilize a scraping device combined with external forces to perform the removal of the sediment layer, which involves frequent manual operations as well as significant capital investment . Physical methods attempt to address the heavy components deposition via lowering the temperature difference between the oil flow and the wall surface through thermal and electromagnetic effects, but this is often expensive and energy-intensive . The application of chemical agents to inhibit the heavy components deposition can have a serious negative effect not only on crude oil quality but also on downstream processing. , A low-cost and efficient technology represented by coating is increasingly being applied to the field of flow assurance in oilfields.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of a Coated Wall on Wax–Asphaltene Molecule Diffusion, Aggregation, and Adhesion Mechanism: A Molecular Dynamics Simulation Study

Wang

Liu

et al. 2022

Energy Fuels

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Coating is increasingly used as a cost-effective strategy for controlling heavy component deposition in waxy crude oil transportation flowlines. This paper systematically investigated the micro influence mechanism of the coated wall on the diffusion, aggregation, and adhesion behavior of wax–asphaltene molecules by the molecular dynamics (MD) method. A set of experiments was performed to determine the properties of the waxy crude oil. For overcoming the limitations of the model simplification of previous MD studies, the MD models based on experimental data were developed to characterize the motion behavior of wax–asphaltene molecules on non-coated and coated wall surfaces, and the simulated densities of crude oil components had an error of less than 5% with the National Institute of Standards and Technology (NIST) data, which showed that the established model was accurate and reliable. The simulation results showed that two condensate oil layers were formed on the non-coated wall surface, the diffusion and aggregation behavior of wax–asphaltene molecules were enhanced under the low-temperature condition, and there was considerably heavy component molecules adhesion to the non-coated wall surface. The analysis of mean square displacement, radial distribution function, and relative concentration distribution revealed that 288.15 K was the peak wax precipitation, which was consistent with the experimental conclusion. It was also found that the presence of low surface energy coating weakened the diffusion of heavy component molecules. The epoxy silicone-coated had the weakest interaction with wax–asphaltene molecules. Moreover, the fact that the coated wall had a certain inhibitory effect on the aggregation and adhesion of wax–asphaltene molecules in the pipeline was proven, where the epoxy silicone-coated had the strongest inhibitory effect. These investigations present new insights and guidance for controlling heavy component deposition by coating in the pipeline transportation process of waxy crude oil.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of a Coated Wall on Wax–Asphaltene Molecule Diffusion, Aggregation, and Adhesion Mechanism: A Molecular Dynamics Simulation Study

Wang

Liu

et al. 2022

Energy Fuels

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“…In order to overcome the challenges on ASP floodingproduced water, scholars have performed a series of basic studies on the emulsion stability mechanism. Wang et al 14 investigated the effects of oil-displacing agent composition on the oil/water emulsion stability by interfacial tension (IFT) meters, microscopes, and zeta potential analyzers. Both alkali and surfactants play dual roles in the ASP system.…”

Section: Introductionmentioning

confidence: 99%

Effect of Oil-Displacing Agent Composition on Oil/Water Interface Stability of the Asphaltene-Rich ASP Flooding-Produced Water

Liu

Sun

et al. 2022

Langmuir

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In this work, the effect of oil-displacing agent composition on oil/water interface stability of the asphaltene-rich alkali–surfactant–polymer (ASP) flooding-produced water was systematically investigated, especially from the perspective of the interaction between oil displacement agents and asphaltene at the oil/water interface. Primarily, adsorption behavior of the artificial and natural interfacial substances (oil displacement surfactant and asphaltenes) on the oil/water interface was investigated by molecular dynamics simulation. The oil displacement surfactant and asphaltenes formed a cross-linked and compact interfacial film structure, which significantly enhanced the interface stability; the more the oil displacement surfactants adsorbed on the interface, the more stable is the cross-linked structure formed between them and asphaltenes. Then, the interfacial property variations that are originating from the interactions differences between oil displacement agents and asphaltenes were monitored via interfacial tension, zeta potential, and interfacial film rheology tests. Moreover, the effect of oil displacement agent concentrations on the interfacial film thinning and rupture kinetic behavior was further investigated. Finally, cream experiments were conducted to verify the effect of oil displacement agent composition on the oil/water separation efficiencies of asphaltene-rich ASP flooding-produced water. When 5% asphaltenes was added, the creaming oil removal rate reduced from 90.0 to 85.3% at 19 h. The interactions between asphaltenes and oil displacement agents immensely enhance the oil/water interfacial film strength and impede the oil/water separation process.

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“…Compared with experimental analysis methods, molecular dynamics (MD) simulation has unique advantages in microstructure characterization; so in recent years, it has become a trend to explore the aggregation structure of asphaltene and resin molecules from the microscale by molecular simulation [15]. Many studies have shown that the interaction between polar molecules is mainly through the π − π stacking of aromatic rings.…”

Section: Introductionmentioning

confidence: 99%

Effect of Polar Molecule Aggregation on the Stability of Crude Oil/Water Interface: A Molecular Simulation Study

Zhao¹,

Xia²,

Wang³

et al. 2021

Lithosphere

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To ensure the efficient operation of crude oil dehydration and sewage treatment technology in oilfield surface production system, the effect mechanism of polar components represented by asphaltene and resin on the formation and stability of oil-water emulsion needs to be revealed at nanoscale. In this paper, the molecular dynamics simulation method was used to construct the crude oil/polar component/water system models with different molar ratios of asphaltene to resin by adjusting the number of asphaltene and resin molecules, so as to reveal the molecular arrangement and aggregation process and film forming characteristics of asphaltene, resin, and their mixture at the oil-water interface. The simulated results showed that the aggregation process of asphaltene molecules under the influence of hydrogen bonds can be divided into three stages. The addition of resin molecules enhanced the connection between molecules of all polar components at the interface. The π−π stacking and T-shaped stacking structures were found in all aggregations, and the higher the molar ratio of asphaltene molecules, the higher the proportion of π−π stacking structure. With the increase of the molar ratio of asphaltene to resin increases from 0 : 1 to 1 : 0, the interfacial film thickness and interface formation energy increase from 2.366 nm and -143.89 kJ/mol to 3.796 nm and -304.09 kJ/mol, respectively, which indicated that asphaltene molecules play a more significant role in promoting the formation of interfacial film and maintaining its structural stability than resin molecules. The investigations in this study provide theoretical support for demulsification of the crude oil emulsion.

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Molecular Dynamics-Based Simulation on Chemical Flooding Produced Emulsion Formation and Stabilization: A Critical Review

Cited by 34 publications

References 64 publications

Effect of a Coated Wall on Wax–Asphaltene Molecule Diffusion, Aggregation, and Adhesion Mechanism: A Molecular Dynamics Simulation Study

Effect of a Coated Wall on Wax–Asphaltene Molecule Diffusion, Aggregation, and Adhesion Mechanism: A Molecular Dynamics Simulation Study

Effect of Oil-Displacing Agent Composition on Oil/Water Interface Stability of the Asphaltene-Rich ASP Flooding-Produced Water

Effect of Polar Molecule Aggregation on the Stability of Crude Oil/Water Interface: A Molecular Simulation Study

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