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Asphaltene Stability

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Jill S Buckley – One of the best experts on this subject based on the ideXlab platform.

  • SCA2003-01: EFFECT OF CRUDE OIL COMPOSITION ON WETTABILITY OF MICA
    , 2020
    Co-Authors: Lei Yang, Jianxin Wang, Jill S Buckley

    Abstract:

    While many factors are recognized as influencing reservoir wetting, they do so primarily by controlling the fate of components of the crude oil. Surface mineralogy, brine composition, temperature, pressure, and history of fluid occupation all are important variables, but if the oil does not contain species capable of adsorbing or depositing, reservoir rocks, the majority of which are initially water-wet, would remain in their original water-wet condition, while minerals that are naturally oil-wet would also be unchanged. In this study we focus on specific features of the composition of produced oil samples and relate them to the extent to which these oils alter the wetting of mica surfaces under controlled conditions. Wetting alteration tests were designed to control water film Stability. The extent of wetting alteration was quantified by measurements of probe fluid contact angles. Oil properties were selected on the basis of previous studies that indicated the importance of ionizable species and Asphaltene Stability in the produced oil samples. Statistical tests between single variables and contact angles show little evidence of correlation, but more significant relationships were found using linear multivariate analyses and non-linear artificial neural networks.

  • Verification of Asphaltene-InStability-Trend (ASIST) Predictions for Low-Molecular-Weight Alkanes
    Spe Production & Operations, 2009
    Co-Authors: Jefferson L Creek, Jianxin Wang, Jill S Buckley

    Abstract:

    Summary Anticipating when and where Asphaltenes may flocculate during oil production is a key step in successfully preventing or mitigating Asphaltene problems in the field. Because there will be no deposition without precipitation, mapping of Asphaltene Stability over a wide range of temperature, pressure, and composition is required. The ASIST allows the determination of the onset of Asphaltene inStability to be established with a series of liquid n-alkanes. These data are used to predict Asphaltene Stability of live fluids by extrapolating the onset condition from the base data to reservoir conditions by use of a linear extrapolation of the onset solubility parameter vs. square root of the partial molar volume of the precipitant. This extrapolation has been demonstrated previously to be accurate for methane and a model oil. The present work verifies that such an extrapolation is valid for predicting the Asphaltene inStability for mixtures of methane, ethane, and propane with a representative stock-tank oil (STO). The STO was combined with known amounts of methane, ethane, or propane. The Asphaltene onset pressure was determined by a combination of near-infrared (NIR) light scattering and microscopic observation. The onset conditions at ambient pressures were examined for flocculation periods ranging from 20 minutes to 24 hours. Onset pressures calculated with the 5-hour ASIST trends compared well with measured onset pressures.

  • development of a general method for modeling Asphaltene Stability
    Energy & Fuels, 2009
    Co-Authors: Francisco M Vargas, George J. Hirasaki, Jefferson L Creek, Jill S Buckley, Jianxin Wang, Doris L Gonzalez, Walter G. Chapman

    Abstract:

    Asphaltenes constitute a potential problem in deep-water production because of their tendency to precipitate and deposit. A universal model to predict the Stability of these species, under different conditions, is desirable to identify potential Asphaltene problems. In our study, we present important advances in developing a general method to model Asphaltene Stability in oil. The perturbed chain-statistical associating fluid theory equation of state (PC-SAFT EoS), which has been previously validated, has been used to generate simulation data for a model oil containing different Asphaltene precipitants. When dimensionless parameters are defined, the equilibrium curves of different multicomponent mixtures collapse onto one single curve. Universal plots for the bubble point and the onset of Asphaltene precipitation have been obtained, which are in excellent agreement with results obtained from simulations. Extension of this model to mixtures containing dissolved gases, such as methane, CO2, and ethane, is a…

Jianxin Wang – One of the best experts on this subject based on the ideXlab platform.

  • SCA2003-01: EFFECT OF CRUDE OIL COMPOSITION ON WETTABILITY OF MICA
    , 2020
    Co-Authors: Lei Yang, Jianxin Wang, Jill S Buckley

    Abstract:

    While many factors are recognized as influencing reservoir wetting, they do so primarily by controlling the fate of components of the crude oil. Surface mineralogy, brine composition, temperature, pressure, and history of fluid occupation all are important variables, but if the oil does not contain species capable of adsorbing or depositing, reservoir rocks, the majority of which are initially water-wet, would remain in their original water-wet condition, while minerals that are naturally oil-wet would also be unchanged. In this study we focus on specific features of the composition of produced oil samples and relate them to the extent to which these oils alter the wetting of mica surfaces under controlled conditions. Wetting alteration tests were designed to control water film Stability. The extent of wetting alteration was quantified by measurements of probe fluid contact angles. Oil properties were selected on the basis of previous studies that indicated the importance of ionizable species and Asphaltene Stability in the produced oil samples. Statistical tests between single variables and contact angles show little evidence of correlation, but more significant relationships were found using linear multivariate analyses and non-linear artificial neural networks.

  • Verification of Asphaltene-InStability-Trend (ASIST) Predictions for Low-Molecular-Weight Alkanes
    Spe Production & Operations, 2009
    Co-Authors: Jefferson L Creek, Jianxin Wang, Jill S Buckley

    Abstract:

    Summary Anticipating when and where Asphaltenes may flocculate during oil production is a key step in successfully preventing or mitigating Asphaltene problems in the field. Because there will be no deposition without precipitation, mapping of Asphaltene Stability over a wide range of temperature, pressure, and composition is required. The ASIST allows the determination of the onset of Asphaltene inStability to be established with a series of liquid n-alkanes. These data are used to predict Asphaltene Stability of live fluids by extrapolating the onset condition from the base data to reservoir conditions by use of a linear extrapolation of the onset solubility parameter vs. square root of the partial molar volume of the precipitant. This extrapolation has been demonstrated previously to be accurate for methane and a model oil. The present work verifies that such an extrapolation is valid for predicting the Asphaltene inStability for mixtures of methane, ethane, and propane with a representative stock-tank oil (STO). The STO was combined with known amounts of methane, ethane, or propane. The Asphaltene onset pressure was determined by a combination of near-infrared (NIR) light scattering and microscopic observation. The onset conditions at ambient pressures were examined for flocculation periods ranging from 20 minutes to 24 hours. Onset pressures calculated with the 5-hour ASIST trends compared well with measured onset pressures.

  • development of a general method for modeling Asphaltene Stability
    Energy & Fuels, 2009
    Co-Authors: Francisco M Vargas, George J. Hirasaki, Jefferson L Creek, Jill S Buckley, Jianxin Wang, Doris L Gonzalez, Walter G. Chapman

    Abstract:

    Asphaltenes constitute a potential problem in deep-water production because of their tendency to precipitate and deposit. A universal model to predict the Stability of these species, under different conditions, is desirable to identify potential Asphaltene problems. In our study, we present important advances in developing a general method to model Asphaltene Stability in oil. The perturbed chain-statistical associating fluid theory equation of state (PC-SAFT EoS), which has been previously validated, has been used to generate simulation data for a model oil containing different Asphaltene precipitants. When dimensionless parameters are defined, the equilibrium curves of different multicomponent mixtures collapse onto one single curve. Universal plots for the bubble point and the onset of Asphaltene precipitation have been obtained, which are in excellent agreement with results obtained from simulations. Extension of this model to mixtures containing dissolved gases, such as methane, CO2, and ethane, is a…

Humberto Soscun – One of the best experts on this subject based on the ideXlab platform.

  • Theoretical Study of the σ–π and π–π Interactions in Heteroaromatic Monocyclic Molecular Complexes of Benzene, Pyridine, and Thiophene Dimers: Implications on the Resin–Asphaltene Stability in Crude Oil
    Energy & Fuels, 2011
    Co-Authors: Olga Castellano, Raquel Gimon, Humberto Soscun

    Abstract:

    Asphaltenes are molecular structures that are composed of polyaromatic and polyheteroaromatic condensed nuclei, where benzene, pyridine, and thiophene rings are the smallest basic structural units. A deep understanding of the electronic features governing the interaction between these primary units is essential for subsequent rationalization of the nature of larger scale inter-and intramolecular interactions between Asphaltenes, which could help to enrich the knowledge of why these compounds tend to aggregate and then to flocculate in oil operation processes. In this work, we study the intermolecular interaction potentials of benzene―benzene, thiophene-thiophene, pyridine―pyridine, benzene―pyridine, benzene―thiophene, and pyridine-thiophene molecular complexes by using the self-consistent generalized gradient approximation density functional theory with the Perdew—Wang 91 functional (DFT/GGA PW91) in conjunction with the DNP double numerical basis set. In order to understand the dominant electronic interaction of these complexes in terms of the σ―π and π―π electronic interactions, the three most important structural conformations (parallel, antiparallel, and T-shaped) were chosen. These calculations were performed with the DMol3Materials Studio 4.0 program. It was found that the results of the interaction energies calculated with DFT/GGA PW91 are consistent with those reported in the literature for benzene and thiophene dimers. To gain insight about the Stability of the studied complexes, their molecular interaction polarizability was evaluated at the PW91PW91/6-31+G(d,p) level of theory. This property allowed us to explain the attraction and repulsion that occur in these dimer formation processes. These statements were also corroborated at the MP2 and MP4 levels of theory for benzene, pyridine, and thiophene homodimer parallel conformations. Additional CCSD/6-31+G(d,p) calculations were performed for the interaction energies of these dimers. To correlate these findings with the Stability of crude oil, a real Asphaltene and resin dimer complex structure was fully optimized at the PW91/DNP level. The results of interaction energy, which is in good agreement with the value predicted in the literature, and the large value of the interaction polarizability allowed us to explain the Stability of these systems.

  • theoretical study of the σ π and π π interactions in heteroaromatic monocyclic molecular complexes of benzene pyridine and thiophene dimers implications on the resin Asphaltene Stability in crude oil
    Energy & Fuels, 2011
    Co-Authors: Olga Castellano, Raquel Gimon, Humberto Soscun

    Abstract:

    Asphaltenes are molecular structures that are composed of polyaromatic and polyheteroaromatic condensed nuclei, where benzene, pyridine, and thiophene rings are the smallest basic structural units. A deep understanding of the electronic features governing the interaction between these primary units is essential for subsequent rationalization of the nature of larger scale inter-and intramolecular interactions between Asphaltenes, which could help to enrich the knowledge of why these compounds tend to aggregate and then to flocculate in oil operation processes. In this work, we study the intermolecular interaction potentials of benzene―benzene, thiophene-thiophene, pyridine―pyridine, benzene―pyridine, benzene―thiophene, and pyridine-thiophene molecular complexes by using the self-consistent generalized gradient approximation density functional theory with the Perdew—Wang 91 functional (DFT/GGA PW91) in conjunction with the DNP double numerical basis set. In order to understand the dominant electronic interaction of these complexes in terms of the σ―π and π―π electronic interactions, the three most important structural conformations (parallel, antiparallel, and T-shaped) were chosen. These calculations were performed with the DMol3Materials Studio 4.0 program. It was found that the results of the interaction energies calculated with DFT/GGA PW91 are consistent with those reported in the literature for benzene and thiophene dimers. To gain insight about the Stability of the studied complexes, their molecular interaction polarizability was evaluated at the PW91PW91/6-31+G(d,p) level of theory. This property allowed us to explain the attraction and repulsion that occur in these dimer formation processes. These statements were also corroborated at the MP2 and MP4 levels of theory for benzene, pyridine, and thiophene homodimer parallel conformations. Additional CCSD/6-31+G(d,p) calculations were performed for the interaction energies of these dimers. To correlate these findings with the Stability of crude oil, a real Asphaltene and resin dimer complex structure was fully optimized at the PW91/DNP level. The results of interaction energy, which is in good agreement with the value predicted in the literature, and the large value of the interaction polarizability allowed us to explain the Stability of these systems.