Physical and chemical aspects of “precursor films” spreading on water from natural bitumen

Gonzalez, Valeska; Taylor, Spencer E.

doi:10.1016/j.petrol.2018.06.085

Cited by 6 publications

(9 citation statements)

References 56 publications

(106 reference statements)

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“…EDAX elemental analysis results revealed that these are mostly composed of carbon (99.87%). The smooth nanosheets could easily fold and wrinkle and their thickness was about 15–35 nm, which is in excellent agreement with previous studies. ,− They provided a large surface area on which asphaltene aggregates (Figure c) and fine clay particles (Figure e) adsorbed from the bulk solution, increasing the surface roughness. A recent study showed that small- and medium- sized asphaltene clusters are more prone to adsorb on surfaces than larger ones, due to their high mass diffusivity .…”

Section: Resultssupporting

confidence: 91%

Characterization of the Interfacial Material in Asphaltenes Responsible for Oil/Water Emulsion Stability

2020

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This study aimed at a better understanding of the structure and properties of the most interfacially active asphaltenes responsible for the stability of oil/water emulsions. Interfacial material (IM) was extracted from three different crude oils using a modified solvent washing procedure. Structural parameters of IM were analyzed and compared to those of a parent asphaltene. High-resolution microscopy imaging was performed to correlate IM microstructure to their interfacial properties. Although IM and asphaltene fractions had comparable molecular weights, IM species had a smaller aromatic core than asphaltenes with at least one linear fatty acid chain containing a sulfinic or carboxylic group. This subtle difference conferred them with an amphiphilic character that promoted their self-assembly into 2–6 nm thick worm-like aggregates in solution instead of spherical clusters. IM molecules interacted with water through their fatty acid chains while simultaneously π–π stacking with adjacent molecules. These two types of interactions favored their multilayer growth and the formation of stable interfacial films around water droplets that significantly lowered the oil/water interfacial tension. High-resolution microscopy imaging of the interfacial films revealed the presence of flexible nanosheets that are 10–50 nm thick. The nanosheets provided a large surface area on which asphaltene clusters (smaller than 20 nm) and fine clay particles (100–200 nm) adsorbed. Even though multiple washings were performed to extract IM, there were still traces of asphaltenes present in this fraction as well as 10–30 wt % of clays, depending on the type of crude oil. The latter induced some artifacts when analyzing the properties of the most interfacially active asphaltenes.

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Section: Resultssupporting

confidence: 91%

Characterization of the Interfacial Material in Asphaltenes Responsible for Oil/Water Emulsion Stability

2020

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“…For this elementary analysis, we also assume that γ WS and γ OS remain relatively unaffected by the change in Ca 2+ concentration. However, although we recognize that, in practice it is likely that wetting films comprising, for example, hydrophobic species [101] or hydration layers [102], can modify water/solid and oil/solid interfaces and their respective interfacial energies, predicting the effects on the contact angle, for example, is not easy. Therefore, we consider, as an example, the simple analysis involving the initial and final conditions as introduced above, for which it is apparent that…”

Section: Implications For Crude Oil Surface Chemistrymentioning

confidence: 99%

Metal Ion Interactions with Crude Oil Components: Specificity of Ca2+ Binding to Naphthenic Acid at an Oil/Water Interface

Taylor

Chu

2018

Colloids and Interfaces

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Abstract:On the basis of dynamic interfacial tension measurements, Ca 2+ has been shown specifically to interact with naphthenic acid (NA) at the n-heptane/water interface, consistent with NA adsorption followed by interfacial complexation and formation of a more ordered interfacial film. Optimum concentrations of Ca 2+ and NA have been found to yield lower, time-dependent interfacial tensions, not evident for Mg 2+ and Sr 2+ or for several alkali metal ions studied. The results reflect the specific hydration and coordination chemistry of Ca 2+ seen in biology. Owing to the ubiquitous presence of Ca 2+ in oilfield waters, this finding has potential relevance to the surface chemistry underlying crude oil recovery. For example, "locking" acidic components at water/oil interfaces may be important for crude oil emulsion stability, or in bonding bulk oil to mineral surfaces through an aqueous phase, potentially relevant for carbonate reservoirs. The relevance of the present results to low salinity waterflooding as an enhanced crude oil recovery technique is also discussed.

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“…Chung and Butler concluded that the primary mechanism for the in situ formation of w/o emulsions during SAGD is condensation of steam in contact with bitumen, with the condensing water effectively being engulfed by spreading oil films [71]. "Precursor" oil films that preferentially spread from bitumen over a water surface were studied by Drelich et al more than 20 years ago [78] and have recently been shown [79] to contain a range of polar surface-active components, which could therefore explain water uptake by the oil by this mechanism. However, a second mechanism involves counter-current flow of steam and oil within the steam chamber.…”

Section: What Happens At the Liquid/liquid Interface? Water-in-oil Emmentioning

confidence: 99%

Interfacial Chemistry in Steam-Based Thermal Recovery of Oil Sands Bitumen with Emphasis on Steam-Assisted Gravity Drainage and the Role of Chemical Additives

Taylor

2018

Colloids and Interfaces

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In this article, the importance of colloids and interfaces in thermal heavy oil or bitumen extraction methods is reviewed, with particular relevance to oil sands. It begins with a brief introduction to the chemical composition and surface chemistry of oil sands, as well as steam-based thermal recovery methods. This is followed by the specific consideration of steam-assisted gravity drainage (SAGD) from the perspective of the interfacial chemistry involved and factors responsible for the displacement of bitumen from reservoir mineral surfaces. Finally, the roles of the different chemical additives proposed to improve thermal recovery are considered in terms of their contributions to recovery mechanisms from interfacial and colloidal perspectives. Where appropriate, unpublished results from the author's laboratory have been used to illustrate the discussions.

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Physical and chemical aspects of “precursor films” spreading on water from natural bitumen

Cited by 6 publications

References 56 publications

Characterization of the Interfacial Material in Asphaltenes Responsible for Oil/Water Emulsion Stability

Characterization of the Interfacial Material in Asphaltenes Responsible for Oil/Water Emulsion Stability

Metal Ion Interactions with Crude Oil Components: Specificity of Ca2+ Binding to Naphthenic Acid at an Oil/Water Interface

Interfacial Chemistry in Steam-Based Thermal Recovery of Oil Sands Bitumen with Emphasis on Steam-Assisted Gravity Drainage and the Role of Chemical Additives

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