A small angle x-ray scattering study of the effect of pressure on the aggregation of asphaltene fractions in petroleum fluids under near-critical solvent conditions

Carnahan, Norman F.; Quintero, Lirio; Pfund, David M.; Fulton, John L.; Smith, Richard D.; Capel, Malcolm; Leontaritis, Kosta J.

doi:10.1021/la00032a023

Cited by 73 publications

(60 citation statements)

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“…A critical resin concentration has been suggested as the basis for quantifying asphaltene stability, based on this view of specific interactions between the asphaltene and resin fractions (Leontaritis and Mansoori, 1987). Models of asphaltenes and resins as inverse micelles are based on similar assumptions (Andersen and Birdi, 1991;Carnahan et al, 1993). A contrary view holds that specific interactions between asphaltenes and resins are not required to explain asphaltene stability , that resins are primarily good asphaltene solvents, and that non-polar van der Waals forces are primarily responsible for flocculation of asphaltenes .…”

Section: Introductionmentioning

confidence: 99%

Wettability and Imbibition: Microscopic Distribution of Wetting and Its Consequences at the Core and Field Scales

Buckley¹,

Morrow²,

Palmer³

et al. 2003

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The main objectives of this project are:(1) to quantify the microscopic distribution of altered wetting that occurs in oil reservoirs as crude oil components adsorb on rock surfaces, and (2) to apply quantitative descriptions of wetting at the microscopic level to interpretation of imbibition in mixed-wet porous media. AbstractThe questions of reservoir wettability have been approached in this project from three directions. First, we have studied the properties of crude oils that contribute to wetting alteration in a reservoir. A database of more than 150 different crude oil samples has been established to facilitate examination of the relationships between crude oil chemical and physical properties and their influence on reservoir wetting. In the course of this work an improved SARA analysis technique was developed and major advances were made in understanding asphaltene stability including development of a thermodynamic Asphaltene Solubility Model (ASM) and empirical methods for predicting the onset of instability. The CO-Wet database is a resource that will be used to guide wettability research in the future.The second approach is to study crude oil/brine/rock interactions on smooth surfaces. Contact angle measurements were made under controlled conditions on mica surfaces that had been exposed to many of the oils in the CO-Wet database. With this wealth of data, statistical tests can now be used to examine the relationships between crude oil properties and the tendencies of those oils to alter wetting. Traditionally, contact angles have been used as the primary wetting assessment tool on smooth surfaces. A new technique has been developed using an atomic forces microscope that adds a new dimension to our ability to characterize oil-treated surfaces.Ultimately we aim to understand wetting in porous media, the focus of the third approach taken in this project. Using oils from the CO-Wet database, experimental advances have been made in scaling the rate of imbibition, a sensitive measure of core wetting. Application of the scaling group to mixed-wet systems has been demonstrated for a range of core conditions. Investigations of imbibition in gas/liquid systems provided the motivation for theoretical advances as well.As a result of this project we have many new tools for studying wetting at microscopic and macroscopic scales and a library of well-characterized fluids for use in studies of crude oil/brine/rock interactions.iv Table of , where v p is precipitant molar volume. Fits to these linear trends are summarized in Table I relationship used is that for A-93+ α-MN (Fig. I-3.5) with a temperature adjustment of -0.0008 RI units/°C. Solution gas is estimated to be xiii composed of methane, ethane, and propane with mole fractions of 0.5, 0.4, and 0. Figure I-3.27. Measured and predicted onset conditions for flocculation from crude oils induced by precipitants from n-pentane to n-pentadecane. Asphaltene molar volume = 2500 ml/mol. Other model parameters are given in Figure II-2.8. Example of the "memo...

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Section: Introductionmentioning

confidence: 99%

Wettability and Imbibition: Microscopic Distribution of Wetting and Its Consequences at the Core and Field Scales

Buckley¹,

Morrow²,

Palmer³

et al. 2003

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“…However, some recent X-ray and neutron-scattering results suggest that asphaltene particles appear to be spherical with average radii in the range 3-6 nm (Sheu et al, 1992b;Carnahan et al, 1993;Storm et al, 1994). Rheological and ultramicroscopic studies also suggest an essentially spherical shape of asphaltene particles in crude oil (Pfeiffer and Saal, 1940;Neumann et al, 1981).…”

Section: Introductionmentioning

confidence: 99%

Molecular‐thermodynamic framework for asphaltene‐oil equilibria

1998

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“…[1][2][3] The need for a more efficient exploitation of heavy feedstocks has lead to an increased interest during the last years in elucidating the molecular structure of asphaltenes in order to understand their behaviour in thermal and catalytic processes.…”

Section: Introductionmentioning

confidence: 99%

Molecular Structure and Intermolecular Interaction of Asphaltenes by FT-IR, NMR, EPR

Scotti

Montanari

1998

Structures and Dynamics of Asphaltenes

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A small angle x-ray scattering study of the effect of pressure on the aggregation of asphaltene fractions in petroleum fluids under near-critical solvent conditions

Cited by 73 publications

References 0 publications

Wettability and Imbibition: Microscopic Distribution of Wetting and Its Consequences at the Core and Field Scales

Wettability and Imbibition: Microscopic Distribution of Wetting and Its Consequences at the Core and Field Scales

Molecular‐thermodynamic framework for asphaltene‐oil equilibria

Molecular Structure and Intermolecular Interaction of Asphaltenes by FT-IR, NMR, EPR

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