Mechanisms of asphaltene aggregation in toluene–heptane mixtures

Yudin, I. K.; Nikolaenko, G. L.; Городецкий, Е. Е.; Kosov, V.I.; Melikyan, V.R.; Markhashov, E.L; Frot, D.; Briolant, Y.

doi:10.1016/s0920-4105(98)00033-3

Cited by 113 publications

(126 citation statements)

References 8 publications

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“…This precipitation phenomenon, close to flocculation onset conditions, leads to time-dependent aggregation in the volume [54,55]. It has been shown recently [45,56] that these conditions favour deposition at the solid/liquid interface by a multilayer growth process.…”

Section: Colloidal Stabilitymentioning

confidence: 91%

Relation between Nanoscale Structure of Asphaltene Aggregates and their Macroscopic Solution Properties

Barré

Jestin

Morisset

et al. 2009

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Relation entre nanostructure des agrégats d'asphaltène et les propriétés macroscopiques de leur solution -Certaines propriétés particulières de bruts pétroliers sont attribuées à leur fraction la plus dense, lourde et polaire : les asphaltènes. La compréhension de l'origine de ces propriétés repose sur une description structurale fine de ces fractions. Nous présentons une caractérisation des solutions d'asphaltène, à l'échelle du nanomètre, basée sur de nouvelles ou récentes expériences de diffusion de rayonnement (rayons X ou neutrons) à partir desquelles des paramètres structuraux des agrégats d'asphaltène (R g , M w et A 2 ) sont déduits. La dépendance de ces paramètres est compatible avec un modèle d'agrégats de type fractal de masse. Ce modèle rend compte de toute la variété de propriétés macroscopiques de ces solutions. En particulier, la prise en compte de l'aspect solvaté des agrégats permet de prédire la viscosité de solutions d'asphaltène en fonction de leur concentration. D'autre part, les asphaltènes s'adsorbent aux interfaces liquide-liquide et liquide-solide et forment des monocouches dont l'épaisseur est du même ordre de grandeur que la taille des agrégats de la solution. L'analyse des isothermes d'adsorption, les expériences de réflectivité des neutrons ainsi que les expériences de diffusion des neutrons en conditions d'extinction de contraste, mettent en évidence une densification des agrégats d'asphaltène dans la couche adsorbée relativement à leur état solvaté dans le volume. Enfin, la résultante des interactions attractives/répulsives entre agrégats peut être reliée à la stabilité relative d'émulsions d'eau dans l'huile et à la stabilité d'effluents d'hydroconversion. Cette approche de mise en relation entre structure et propriété permet d'asseoir et de justifier le modèle de fractal de masse qui est discuté. Abstract

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Section: Colloidal Stabilitymentioning

confidence: 91%

Relation between Nanoscale Structure of Asphaltene Aggregates and their Macroscopic Solution Properties

Barré

Jestin

Morisset

et al. 2009

Oil & Gas Science and Technology - Rev. IFP

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“…The initial concentration of 1500 mg/L is the good choice for this experiment. Because it is lower than critical clustering concentration of asphaltene in toluene (≈2000 mg/L) [24]. Therefore, with selection of this concentration, the contribution of the asphaltene selfassociation to the adsorbed mass of the asphaltene was decreased [25].…”

Section: Estimation Of Proper Amount Of Nanoparticles For Asphaltene mentioning

confidence: 98%

Investigation of Asphaltene Adsorption onto Zeolite Beta Nanoparticles to Reduce Asphaltene Deposition in a Silica Sand Pack

Kashefi

Lotfollahi

Shahrabadi³

2018

Oil & Gas Science and Technology - Rev. IFP Energies nouvel

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-Zeolite beta nanoparticles were used as a new asphaltene adsorbent for reducing asphaltene deposition during fluid injection into a silica sand pack. At first, the asphaltene adsorption efficiency and capacity of zeolite beta nanoparticles were determined by UV-Vis spectrophotometer. It was found that the proper concentration of nanoparticles for asphaltene adsorption was 10 g/L and the maximum asphaltene adsorption onto zeolite beta was 1.98 mg/m 2 . Second, two dynamic experiments including co-injection of crude oil and n-heptane (as an asphaltene precipitant) with and without use of zeolite beta nanoparticles in the sand pack was carried out. The results showed that the use of zeolite beta nanoparticles increased the permeability ratio and outlet fluid's asphaltene content about 22% and 40% compared to without use of nanoparticles, respectively. Moreover, a model based on monolayer asphaltene adsorption onto nanoparticles and asphaltene deposition mechanisms including surface deposition, entrainment and pore throat plugging was developed to determine formation damage during co-injection of crude oil and n-heptane into the sand pack. The proposed model presented good prediction of permeability and porosity ratios with AAD% of 1.07 and 0.07, respectively.

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“…One of the most promising techniques to monitor in real time the kinetics of asphaltene aggregation and measure a changing size of the aggregates is the dynamic light scattering (DLS) [32][33][34]. It allows determining the value of the threshold concentration of precipitant that characterizes so called "zero rate of aggregation" -the stability threshold of system.…”

Section: Resultsmentioning

confidence: 99%

“…Toluene-heptane system used is a widely accepted model system for studying the properties of the asphaltenes [32][33][34].…”

Section: Methodsmentioning

confidence: 99%

Supramolecular Structures of Oil Systems as the Key to Regulation of Oil Behavior

Az¹,

Ee²,

Vn³

et al. 2013

J Pet Environ Biotechnol

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The paper is devoted to investigation of supramolecular structures formed by high-molecular components of oil -asphaltenes and waxes. Petroleum asphaltenes that are characterized by their ability to self-organization can be considered as a polydisperse system. The aggregation of A1and A2 asphaltenes both in toluene solution and in diluted heavy oils was studied by dynamic light scattering technique. The stabilizing role of resins was confirmed. Due to the fact that the supramolecular structures in oils can be also formed by high molecular microcrystalline waxes, their influence as well as A1 and A2 asphaltenes on wax crystallization process was evaluated using optical microscopy. The effect of the different molecular structures of asphaltenes (A1 and A2) on the rheological properties of crude oils was also observed. Self-organization of asphaltenes directly in heavy high-viscosity oils with high content of resins was investigated by varying the ratios oil:precipitant. It was shown that extremely stable supramolecular structures in heavy oils had been formed. The influence of ultrasonic action for the destruction of stable supramolecular structures and the reduction of oil viscosity were considered.Also petroleum asphaltenes can be the indicators of many processes that occur in the reservoir. We have shown the possibility of using the gradient of asphaltenes, as well as their structure, to confirm the influx of deep light hydrocarbons in carbonate reservoirs. Thus, all obtained results of investigation of structure formation processes will let regulate the macroscopic properties of heavy oils in the future and identify the processes occurring in the reservoir.

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Mechanisms of asphaltene aggregation in toluene–heptane mixtures

Cited by 113 publications

References 8 publications

Relation between Nanoscale Structure of Asphaltene Aggregates and their Macroscopic Solution Properties

Relation between Nanoscale Structure of Asphaltene Aggregates and their Macroscopic Solution Properties

Investigation of Asphaltene Adsorption onto Zeolite Beta Nanoparticles to Reduce Asphaltene Deposition in a Silica Sand Pack

Supramolecular Structures of Oil Systems as the Key to Regulation of Oil Behavior

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