Methodology for Predicting the Phase Envelope of a Heavy Crude Oil and Its Asphaltene Deposition Onset

López-Chávez, Ernesto; Pacheco-Sánchez, J. H.; Martínez-Magadán, José Manuel; Castillo-Alvarado, Fray de Landa; Soto-Figueroa, César; García–Cruz, Isidoro

doi:10.1080/10916460601054180

Cited by 10 publications

(6 citation statements)

References 37 publications

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“…Our work predicts that the plot of upper onset pressure tends to be parallel to or away from that of the saturation pressure at high temperatures. This is in agreement with the theories in the literature. − , However, some of the theories predict that these two plots may eventually meet. , The difference is possibly due to different reservoir oils. After a careful literature search, we do not notice any direct experimental evidence to support either of the predictions.…”

Section: Resultssupporting

confidence: 91%

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Cubic-Plus-Association Equation of State for Asphaltene Precipitation in Live Oils

2010

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We apply a cubic-plus-association equation of state (CPA-EOS) to study the asphaltene precipitation in live oils from temperature, pressure, and composition effects. The live oils are characterized by considering the pure components, the pseudo-hydrocarbon components, and the hydrocarbon residue. The hydrocarbon residue is further divided into the “heavy” component and asphaltenes. The asphaltene precipitation is modeled as liquid−liquid equilibrium between the upper onset and bubble point pressures and as gas−liquid−liquid equilibrium between the bubble point and lower onset pressures. In our work, the self-association between asphaltene molecules and the cross-association between asphaltene and “heavy” molecules are taken into account. The EOS parameters are either directly available, from our recent work, or from fitting the bubble point pressure. The cross-association energy between asphaltene and “heavy” molecules depends upon the temperature but is independent of the pressure. We reproduce the experiments of the amount and onset pressures of asphaltene precipitation in several live oils over a broad range of composition, temperature, and pressure conditions.

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Section: Resultssupporting

confidence: 91%

“…[23][24][25][26]28 However, some of the theories predict that these two plots may eventually meet. 18,56 The difference is possibly due to different reservoir oils. After a careful literature search, we do not notice any direct experimental evidence to support either of the predictions.…”

Section: Resultsmentioning

confidence: 99%

Cubic-Plus-Association Equation of State for Asphaltene Precipitation in Live Oils

2010

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“…To investigate the efficiency of heteroatom substitutions on improving the performance of PPA in an interaction with asphaltene molecules, at least in noncovalent reaction paths, we examined the interaction of a short-chain PPA molecule with an island-type asphaltene molecule containing more heteroatoms than those of a usual asphaltene molecule. This asphaltenic structure, shown in Table , was proposed by Speight and Moschopedis based on the asphaltene average molecular structure in 1981. , Regardless of the structural precision of the Speight model, which was improved in the next years, this asphaltene model molecule with a higher percentage of heteroatoms was used here to compare the interaction energy between highly polar asphaltene–PPA and nonpolar asphaltene–PPA. To build a hypothetical nonpolar asphaltene, all the heteroatoms in the Speight model of asphaltene were replaced by C atoms.…”

Section: Resultsmentioning

confidence: 99%

“…This asphaltenic structure, shown in Table 2, was proposed by Speight and Moschopedis based on the asphaltene average molecular structure in 1981. 48,49 Regardless of the structural precision of the Speight model, which was improved in the next years, this asphaltene model molecule with a higher percentage of heteroatoms was used here to compare the interaction energy between highly polar asphaltene−PPA and nonpolar asphaltene−PPA. To build a hypothetical nonpolar asphaltene, all the heteroatoms in the Speight model of asphaltene were replaced by C atoms.…”

Section: ■ Introductionmentioning

confidence: 99%

Moderating Effects of Paraffin Wax on Interactions between Polyphosphoric Acid and Bitumen Constituents

Mousavi

Fini

2019

ACS Sustainable Chem. Eng.

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Despite the merits of using polyphosphoric acid (PPA) in modification of bitumen, its desirable stiffening effect on bitumen is totally composition-dependent. While asphaltenes and resins are correctly introduced as the immediate components affected by PPA, our laboratory rheological investigations show that bitumen's wax content could be a potential interference for PPA's modification function. As evidenced by the complex viscosity test, PPA is very effective in low-wax bitumen, but its effect on high-wax bitumen is quite negligible. In a high-wax medium, the trend of interaction energy improvement with the number of wax chains suggests that the crystalline networks of wax can interfere in interactions of PPA with either asphaltene or resin through concealing interaction sites of asphaltene and resin. This in turn leads to the reduction of their accessible active sites for interacting with PPA. To study the working mechanism of PPA on bitumen constituents, the density functional theory (DFT) approach and energy decomposition analysis (EDA) were performed on the pairs of PPA−asphaltene, PPA−resin, and PPA−wax molecules. In the case of the PPA−asphaltene interaction, EDA shows clear contributions of electrostatic, orbital, and dispersion forces. In the resin fraction, the strong interactions between basic sites of the resin molecules and PPA lead to the formation of ion-pair compounds stabilized through oppositely charged ions held together via Coulombic attraction. The formation of these new entities, which are often nonsoluble in heptane, can further explain the decrease of resin content after PPA modification. The reduction of resin is followed by an increase in the content of asphaltene with a smaller molecular weight in n-heptane precipitates, which is in line with our experiments and that of other researchers.

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“…Predictive tools based on scaling equation, corresponding states, and correlations have also been reported in the literature. ,,− These tools may, however, be limited to specific systems. Recently, application of mathematical correlations has been investigated for predictions of the amount of asphaltene precipitation. ,, Ashoori et al have used the artificial neural network (ANN) in comparison with the scaling laws and found out that the prediction results of the latter network are more accurate than the modified scaling equations proposed by Rassamdana et al and Hu et al , However, ANN based models should be used very carefully because they may face over-fitting or under-fitting problems.…”

Section: Introductionmentioning

confidence: 99%

Monodisperse Thermodynamic Model Based on Chemical + Flory–Hüggins Polymer Solution Theories for Predicting Asphaltene Precipitation

Mohammadi

Eslamimanesh

Richon

2012

Ind. Eng. Chem. Res.

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Asphaltene precipitation is traditionally modeled using the Flory−Huggins polymer solution theory. The existing thermodynamic models, generally, do not take into account the aggregation/association phenomena in the system. This work aims at providing a monodisperse thermodynamic model for estimating asphaltene precipitation by taking into account the aforementioned phenomena. The chemical theory of associated solutions with physical interactions along with the Flory− Huggins polymer solution theory is applied to develop this model. The results of this method are compared with some selected experimental data from the literature. It is shown that taking into account the aggregation/association phenomena in the system can lead to better predictions of the model. Moreover, it is shown that this method simplifies to the existing activity coefficient based models when ignoring the association.

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Methodology for Predicting the Phase Envelope of a Heavy Crude Oil and Its Asphaltene Deposition Onset

Cited by 10 publications

References 37 publications

Cubic-Plus-Association Equation of State for Asphaltene Precipitation in Live Oils

Cubic-Plus-Association Equation of State for Asphaltene Precipitation in Live Oils

Moderating Effects of Paraffin Wax on Interactions between Polyphosphoric Acid and Bitumen Constituents

Monodisperse Thermodynamic Model Based on Chemical + Flory–Hüggins Polymer Solution Theories for Predicting Asphaltene Precipitation

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