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Asphaltene precipitation is a challenging problem for the petroleum industry. Changes in pressure, temperature, and composition are key factors that influence asphaltene stability in crude oils. We have …
2.2.1 Precipitation of asphaltenes One of the simplest separations applied to asphalts is the precipitation of asphaltenes. Asphaltenes are that portion of an asphalt that is insoluble in low molecular weight (MW)-saturated alkanes. Asphaltenes are …
A thermodynamic model has been developed to describe the effects of temperature, pressure, and composition on asphaltene precipitation. The proposed model combines regular solution theory with Flory-Huggins polymer solutions theory to predict maximum volume fractions of asphaltene dissolved in oil.
The amount of precipitation is determined by the difference between the total amount of asphaltenes present in the initial oil and the solubility of asphaltene under …
A thermodynamic micellization model is used in this work to describe asphaltene precipitation from Kuwaiti crude oil. The model is based on asphaltene and resin micelle formation and then destruction by addition of an alkane. A coin-like aggregate of asphaltene surrounded by resin molecules constitutes the micellar phase. The rest of …
According to the colloidal theory, asphaltenes form insoluble solid particles in crude oil, which are stabilized by the presence of resins adsorbed onto their surface (see …
Asphaltene precipitation is generally believed to be an irreversible process, which is the main reason it can have a profound impact on production operations. Investigations into asphaltene precipitation have been impeded by a shortage of experimental data and information on precipitation mechanisms.
A coin-like aggregate of asphaltene surrounded by resin molecules constitutes the micellar phase. The rest of the asphaltene and resin are dissolved in the bulk phase. A group contribution method was used to predict the critical properties for the asphaltenes, resin, and oil.
Asphaltenes are that portion of an asphalt that is insoluble in low molecular weight (MW)-saturated alkanes. Asphaltenes are black, friable solids. The solvents used to …
By definition, asphaltene is that component of crude oil which precipitates out by the addition of n -alkanes particularly n -heptane while becomes soluble in aromatic solvents like benzene and toluene [ 4 ]. Compositionally, asphaltenes are composed of carbon, hydrogen and heteroatoms like sulphur, oxygen and nitrogen [ 5 ].
Asphaltene precipitation as changing pressure and temperature is illustrated in Figs. 2 and 3. The first figure is a plot of weight percent asphaltene …
with oil [4]. Asphaltene precipitation is different from flocculation and deposition but all three of them may cause serious damage to the formation. The process of asphaltene precipitation consists of few important steps: (1). first step Sima Sh. Alian, Abdul Aziz Omar, Ali F. Alta'ee and Irzie Hani Study of Asphaltene Precipitation induced
(34) The terms asphaltene precipitation, asphaltene flocculation, and asphaltene deposition are different in terms of mechanism and definition. (35) Precipitation can be explained as asphaltene changes its phase from the …
Asphaltene particles precipitate out of oil continuum due to changes in temperature, pressure or composition. Such changes in operating conditions occur …
Asphaltene precipitation may be triggered deliberately in applications such as solvent deasphalting or unintentionally due to temperature, pressure or composition changes for example when heavy oil is blended with other petroleum fluids. In either case, it is critical to identify the condition at which asphaltenes start precipitating (onset ...
Precipitation of asphaltenes occurs through the formation of such aggregates. The solubility of asphaltenes is therefore a function of temperature, pressure, and the composition of the crude oil. Any action that affects the compositional balance of the crude oil can affect the ability of the oil to maintain the asphaltenes in solution.
Asphaltene precipitation is a perennial problem in production and refinery of crude oils. To avoid precipitation, it is useful to predict the solubility of asphaltenes in petroleum liquids as a function of temperature, pressure and liquid-phase composition. In the molecular-thermodynamic model presented here, both asphaltenes and resins are ...
Asphaltene solubility as a function of pressure, temperature, and composition Operating variables such as the oil flow rate and the length and diameter of the pipeline Constants describing the kinetics of …
Asphaltene precipitation and its subsequent deposition in the wellbore and near-well region are detrimental to oil production. The most effective preventive method is to operate at conditions outside the asphaltene precipitation envelope (APE) (see Asphaltene precipitation ).
The aim of this research study is to estimate asphaltene precipitation envelope (APE) using empirical equations and equation of state model. ... By definition, asphaltene is that component of crude oil which precipitates out by the addition of n-alkanes particularly n-heptane while becomes soluble in aromatic solvents like benzene and …
Asphaltene precipitation is a challenging problem for the petroleum industry. Changes in pressure, temperature, and composition are key factors that influence asphaltene stability in crude oils.
The precipitation of asphaltenes during all phases of crude oil recovery can lead to a decrease in production efficiency. Leontaritis et al. (1994) stated that generally four forms of formation damage induced by asphaltene deposition can be defined: (1) The physical blockage or permeability reduction, (2) wettability alteration, (3) a crude oil ...
The asphaltenes precipitation onset and the precipitation yield were determined for four different crude oil samples. The results confirm that crude oil samples presenting low precipitation onsets effectively present instability and depositional problems in field operations, whereas those with a high onset are stable and do not present …
Asphaltenes are the heaviest, most polar fraction, and least soluble fraction of a crude oil. Asphaltene precipitation may be triggered deliberately in applications such as solvent deasphalting or …
This value of Φr is compared with a critical resin concentration, Φcr, which is given as a function of pressure, temperature, molar volume, and solubility parameters. Φcr is the key parameter of the model. If Φr > Φcr, the system is stable and no precipitation occurs. If Φr ≤ Φcr, asphaltene precipitation occurs.
Asphaltene characteristics discusses the chemistry of asphaltenes and Thermodynamic models for asphaltene precipitationdiscusses the thermodynamic equilibrium of asphaltenes in petroleum fluids. Changes in pressure, temperature, and composition may alter the initial …
Asphaltene is a polyaromatic molecule with heteroatoms and aliphatic chains attached to its core ( Tavakkoli et al., 2015 ). It may also have metals (V, Ni, Fe) and vary …
The precipitation inhibition of asphaltenes and the rheological behaviors of crude oil in the presence of ionic liquid polymers were studied by measuring the initial precipitation point (IPP), turbidity, particle size distribution, and morphology of asphaltenes in model oil. In the presence of same anions (Br ...