Reversibility of Asphaltene Precipitation Using Temperature-Induced Aggregation

Chaisoontornyotin, Wattana; Bingham, Austin W.; Hoepfner, Michael P.

doi:10.1021/acs.energyfuels.6b02344

Cited by 26 publications

(31 citation statements)

References 53 publications

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“…Asphaltenes are polyaromatic molecules found in the crude oil and bitumen that are typically characterized by their solubility, where they are soluble in aromatic solvents, such as benzene or toluene, but insoluble in n-alkanes. During oil production, asphaltenes can precipitate from crude oil and aggregate due to temperature, pressure, and compositional changes that occur when mixing various oil streams during processing, resulting in pipeline plugging, formation damage, and fouling [1][2][3][4][5][6][7]. In particular, asphaltene fouling has been more readily observed during processes involving CO 2 injection for enhanced oil recovery (EOR) [8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Combined interfacial shear rheology and microstructure visualization of asphaltenes at air-water and oil-water interfaces

Lin

Barman

et al. 2018

Journal of Rheology

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Asphaltenes are surface-active polyaromatic molecules in crude oil that are known to deposit in pipelines or stabilize water droplets by flocculating at interfaces resulting highly viscous emulsions, leading to significant flow assurance problems. Commercial dispersants have been developed to disturb asphaltene aggregation to mitigate deposition, but their role on the interfacial properties of asphaltene films is unclear. In this study, we elucidate asphaltene interfacial rheology at air-water and oil-water interfaces at high and low asphaltene surface coverage and in the presence of dispersants. A modified Langmuir trough with double-wall ring rheometer is used to simultaneously visualize the microstructure of asphaltene interface and measure the rheological responses. Two surface coverages, 0.5 and 4 lg cm À2 , show widely different rheological responses at air-water interfaces. Strong yielding behavior was observed for higher coverage while a less yielding behavior and wider linear viscoelastic regime were observed for the lower coverage. Additionally, asphaltenes at decane-water interfaces were less shear-thinning than at air-water interfaces. Surface pressure-area compression-expansion curves show that the interface is more compressible in the presence of commercial chemical dispersants. This combined imaging and interfacial rheology platform provide an effective method to correlate asphaltene microstructure to interfacial rheological properties. V

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Section: Introductionmentioning

confidence: 99%

Combined interfacial shear rheology and microstructure visualization of asphaltenes at air-water and oil-water interfaces

Lin

Barman

et al. 2018

Journal of Rheology

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“…This behavior is not typically reported in the literature, normally asphaltenes are morphologically described as fractal solids that aggregate to form bigger flocks, as the pressure is reduced far from the AOP. 46,47 For this studied crude oil, no fractal particles aggregation is observed still at high gas volume content. For the RC5 and RC6 systems, a wide asphaltene-dominated region is observed, their pressure domain, that is, the difference between AOP and bubble point pressure, goes from 14.5 to 22.9 MPa, respectively.…”

Section: Resultsmentioning

confidence: 77%

“…This behavior is not typical in asphaltenes precipitation, normally associated with the slow kinetics of redissolution and the formation of major aggregates or flocs. 46,47 For stable crude oils, fine and powdery asphaltenes dispersion can be observed. 48−50 Especially for pressures near their asphaltenes onset pressure (AOP), powdery and non-sticking material asphaltene formation is favored, also with rapid redissolution.…”

Section: Resultsmentioning

confidence: 99%

“…This phase seems to appear as a fine particles dispersion, and it was noted that before the complete release of a gas below the saturation pressure, the phase dissolves immediately in the oil phase. This behavior is not typical in asphaltenes precipitation, normally associated with the slow kinetics of redissolution and the formation of major aggregates or flocs. , For stable crude oils, fine and powdery asphaltenes dispersion can be observed. − Especially for pressures near their asphaltenes onset pressure (AOP), powdery and non-sticking material asphaltene formation is favored, also with rapid redissolution …”

Section: Resultsmentioning

confidence: 99%

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Measurement of Fluid Phase Equilibria for High Gas Ratio Mixtures of Carbon Dioxide, Methane, and Brazilian Presalt Crude Oil

et al. 2021

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The phase behavior of petroleum fluids under reservoir conditions provides fundamental information for an adequate crude oil production scheme. Recently, complex phase transitions have been studied for presalt crude oils, involving atypical liquid–liquid–vapor and liquid–liquid–asphalt phase transitions. In this paper, the phase behavior of synthetic mixtures containing carbon dioxide, methane, and a Brazilian presalt crude oil was investigated using PVT, coupled with near-infrared (NIR) transmittance and high-pressure microscopy (HPM) measurements. Crude oil (API 28.0, 0.68 wt % of asphaltenes) was mixed with 25.0 wt % gas (for a CH4/CO2 ratio from 0 to 62.5 wt %), and the phase behavior of the mixture was evaluated at a reservoir temperature of 343.15 K and pressures up to 100 MPa. Black oil phase behavior was detected for systems with a lower CH4/CO2 ratio and lower gas volume fraction, with no asphaltenes precipitation observed. As the CH4/CO2 ratio increased, pressure–volume curves showed a slight phase transition, with a not evident sharp break in the slope because of the minor difference of fluid compressibility. Moreover, a phase insolubility was confirmed by NIR and HPM tests for a high CH4/CO2 ratio that can be associated with the formation of an asphaltic phase. When total molar gas content increases by increasing the CH4/CO2 ratio, the asphaltic phase is formed at higher pressures. However, asphaltenes were detected as an uncommon fine dispersion with no larger fractal aggregates formation, even at pressures far below the asphaltenes onset pressure (AOP). Additionally, a nontypical behavior was observed in HPM tests with a total asphaltene dissolution when pressure reached the bubble pressure point. This atypical redissolution is in accordance with an instantaneous phase dissolving at pressures higher than the AOP, observed for the same oil at high methane ratios.

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“…Changes in pressure, temperature or composition cause the resin layer to shrink followed by asphaltene precipitation [10][11][12][13]. The reversibility or irreversibility of the asphaltene precipitation is not fully understood in the literature, and it is likely to be related to the complex structure of the asphaltene particles [7,14,15].…”

Section: Introductionmentioning

confidence: 99%

Mechanistic study to investigate the effects of different gas injection scenarios on the rate of asphaltene deposition: An experimental approach

Dashti

Zanganeh

Kord

et al. 2020

Fuel

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Asphaltene deposition during enhanced oil recovery (EOR) processes is one of the most problematic challenges in the petroleum industry, potentially resulting in flow blockage. Our understanding of the deposition mechanism with emphasis on the rate of the asphaltene deposition is still in its infancy and must be developed through a range of experiments and modelling studies. This study aims to investigate the rate of asphaltene deposition through a visual study under different gas injection scenarios. To visualise the asphaltene deposition, a high-pressure setup was designed and constructed, which enables us to record high-quality images of the deposition process over time. Present research compares the effects of nitrogen (N2), carbon dioxide (CO2) and methane (CH4) on the rate of asphaltene deposition at different pressures. The experimental results in the absence of gas injection revealed that the rate of asphaltene deposition increases at higher pressures. The results showed that the rate of asphaltene deposition in the case of CO2 injection is 1.2 times faster than CH4 injection at 100 bar pressure. However, N2 injection has less effect on the deposition rate. Finally, it has been concluded that the injection of CO2 leads to more asphaltene deposition in comparison with CH4 and N2. Moreover, the experimental results confirmed that gas injection affects the mechanism of asphaltene flocculation and leads to the formation of bigger 2 flocculated asphaltene particles. The findings of this study can help for a better understanding of the mechanism of the asphaltene deposition during different gas-EOR processes.

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Reversibility of Asphaltene Precipitation Using Temperature-Induced Aggregation

Cited by 26 publications

References 53 publications

Combined interfacial shear rheology and microstructure visualization of asphaltenes at air-water and oil-water interfaces

Combined interfacial shear rheology and microstructure visualization of asphaltenes at air-water and oil-water interfaces

Measurement of Fluid Phase Equilibria for High Gas Ratio Mixtures of Carbon Dioxide, Methane, and Brazilian Presalt Crude Oil

Mechanistic study to investigate the effects of different gas injection scenarios on the rate of asphaltene deposition: An experimental approach

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