Asphaltene Precipitation from a Heavy Crude Oil with CO2 and Solubility of Crude Oil/CO2 Mixtures

Seifried, Christine M.; Hu, Ruizhi; Headen, Thomas F.; Crawshaw, John; Boek, Edo S.

doi:10.3997/2214-4609.201412166

Cited by 3 publications

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“…Although extensive literature reviews cover asphaltene and wax precipitation, to the best of our knowledge, the recent few that have tackled the effect of the supercritical state of injecting gas on asphaltene deposition rather focused on the quantitative deposition. For example, Seifried et al presented that precipitation of asphaltene upon injection of CO 2 is quantitatively different from that induced by hydrocarbon systems . Therefore, in this study, the terminology “aggregation” will be preferential used as it is believed to be the phenomenon preceding deposition.…”

Section: Introductionmentioning

confidence: 93%

Asphaltene Aggregation in Crude Oils during Supercritical Gas Injection

et al. 2016

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This paper presents the aggregation of asphaltenic materials in three dead crude oils, including two heavy samples from Hokkaido (Japan) and an extra heavy sample from Canada. In this study, a modified ASTM D3279 method and PVT test were used to estimate the amount of precipitated asphaltene and the experimental bubble-point pressures of the samples, respectively. Upon which, a crude oil characterization was performed following pseudocomponent approach with the use of molecular weight and specific gravity of single carbon number from oil assay data as distribution variables. A simplified thermodynamic model, derived from the solubility model, was used to correlate the maximum asphaltene soluble with the aggregated amount. This study has highlighted that oil precipitation, during its titration, occurs as a function of both the molecular weight of the titrant and the carbon-to-hydrogen ratio in the asphaltene phase. Furthermore, the kinetics and the stability of intermolecular forces, developed during the miscibility process, are believed to alter oil polarity and gas solubility. More specifically, pressurization of the system [oil-supercritical gas] decreases the solubility parameters of the asphaltene fraction and increases the solvating strength of gas. Both effects were found to occur concurrently. This study has also demonstrated that asphaltenes are less soluble in impure gases compared to the pure one. At/near the bubble-point pressure, the supercritical gas, in contact with the oil, develops a potential as either a flocculant or coagulant. The increase in pseudo equilibrium temperature attained after gas injection was found also to alter asphaltene aggregation.

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Section: Introductionmentioning

confidence: 93%

Asphaltene Aggregation in Crude Oils during Supercritical Gas Injection

et al. 2016

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“…According to their solubilities, asphaltenes are defined as the fraction of oil that is insoluble in low-molecular-weight paraffin and soluble in light aromatic hydrocarbons. , According to the Yens–Mullins theory, the asphaltene structure corresponds to polycyclic aromatic cores of around 7–10 aromatic rings and peripheral cycloalkane substituents surrounded by aliphatic chains containing heavy metals and heteroatoms. Due to the amphiphilic behavior displayed by asphaltene fractions, the formation of colloidal aggregates, the deposition, and accumulation on different surfaces are promoted by changes in the reservoir conditions (such as pressure temperature) and oil chemistry. − In light crude oils with a low asphaltene content, this oil fraction tends to suffer from aggregation, precipitation, and deposition, especially in undersaturated reservoirs with reservoir conditions above the bubble point . In this sense, asphaltene stability is a function of the ratio of asphaltenes to stabilizing compounds in crude oil, such as aromatics and resins .…”

Section: Introductionmentioning

confidence: 99%

Cardanol/SiO₂ Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part I: Novel Nanocomposite Design Based on SiO₂–Cardanol Interactions

et al. 2020

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This study aims to design a novel green nanocomposite based on the synergistic effect between silica nanoparticles (SN) and cardanol (CDN). The latter is an environmentally friendly dispersant compound extracted from the cashew nut shell waste. Three cardanol/SiO2 nanocomposites were synthesized and named as 5CSN, 7CSN, and 9CSN based on the mass fraction of cardanol on the surface of the SiO2 nanoparticles of 5, 7, and 9%, respectively. The nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and total surface acidity through temperature-programmed desorption of NH3 (TPD-NH3). The binding of CDN molecules on the SiO2 surface precedes an increase in hydrodynamic diameter and total surface acidity due to the exposure of the meta-alkyl chain, phenolic −OH groups, and aromatic rings on the nanocomposite surface. Besides, cardanol/SiO2 interactions were explained from adsorption/desorption isotherms, showing a behavior type I under IUPAC classification. Findings suggest that CDN molecules were highly desorbed, especially at CDN initial dosages of up to 25,000 mgh·L–1 with CDN desorbed percentages over 30.5%. Last, the nanocomposites were evaluated as inhibitors of the asphaltene precipitation/deposition through adsorption isotherms and aggregation kinetics of asphaltene. CDN attached to SiO2 nanoparticles leads to a heterogeneous surface with several functional groups that promote the asphaltene uptake and the reduction of their aggregate size. A higher amount of CDN on the SiO2 surface promotes a surface with high heterogeneity favoring its capability to interact with the asphaltene aggregates. It was found that the adsorption of n-C7 asphaltenes onto the surface of the nanocomposite leads to a decrease in the available asphaltenes in the bulk solution, which reduce the collision and fragmentation phenomena of the asphaltene aggregates, leading to reductions in the aggregate sizes of 31.5, 50.9, 57.5, and 58.5% in the presence of SN, 5CSN, 7CSN, and 9CSN, respectively, at a fixed nanocomposite dosage of 500 mg·L–1. Thus, based on the decrease of the mean aggregate size in the liquid phase and the n-C7 asphaltene affinity toward the nanocomposite surface, the evaluated nanomaterials exhibit the following trend: 9CSN > 7CSN > 5CSN > SN. This approach provides an understanding of the role of CDN nanocomposites in the inhibition of asphaltene formation damage via the capture of heavy oil fraction and the decrease of the size of the aggregate in the oil matrix.

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The rheology of crude oil and carbon dioxide mixtures

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2016

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Asphaltene Precipitation from a Heavy Crude Oil with CO2 and Solubility of Crude Oil/CO2 Mixtures

Cited by 3 publications

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Asphaltene Aggregation in Crude Oils during Supercritical Gas Injection

Asphaltene Aggregation in Crude Oils during Supercritical Gas Injection

Cardanol/SiO₂ Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part I: Novel Nanocomposite Design Based on SiO₂–Cardanol Interactions

The rheology of crude oil and carbon dioxide mixtures

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Asphaltene Precipitation from a Heavy Crude Oil with CO2 and Solubility of Crude Oil/CO2 Mixtures

Cited by 3 publications

References 0 publications

Asphaltene Aggregation in Crude Oils during Supercritical Gas Injection

Asphaltene Aggregation in Crude Oils during Supercritical Gas Injection

Cardanol/SiO2 Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part I: Novel Nanocomposite Design Based on SiO2–Cardanol Interactions

The rheology of crude oil and carbon dioxide mixtures

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Cardanol/SiO₂ Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part I: Novel Nanocomposite Design Based on SiO₂–Cardanol Interactions