Separation of SAGD produced emulsions through a combined pre-dewatering and demulsification process

Shu, Guanli; Bu, Kuiyong; Zhao, Bo; Zheng, Sixun

doi:10.1016/j.petrol.2021.108493

Cited by 6 publications

(3 citation statements)

References 21 publications

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“…Diluent and demulsifiers are added to the produced emulsion, which is sent to a free water knockout unit, where most of the water is removed. In the last step, the produced water–oil emulsion is pumped into horizontal treaters, where the oil is separated from the water by gravity . However, under certain circumstances, stable emulsions (also known as “rag layers”) form near the oil/water interface, causing process disruptions .…”

Section: Introductionmentioning

confidence: 99%

“…In the last step, the produced water−oil emulsion is pumped into horizontal treaters, where the oil is separated from the water by gravity. 35 However, under certain circumstances, stable emulsions (also known as "rag layers") form near the oil/water interface, causing process disruptions. 36 If not detected and eliminated in time, such stable emulsion can occupy the entire separation vessel volume and lead to a shutdown and/or diversion of produced emulsion to the separation train.…”

Section: Introductionmentioning

confidence: 99%

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Asphaltene Precipitation Onsets in Relation to the Critical Dilution of Athabasca Bitumen in Paraffinic Solvents

et al. 2022

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Current water separation processes associated with oil sands recovery are specifically designed to operate either below or above the critical dilution of bitumen by solvent, defined as the onset of bulk asphaltene precipitation. Oil−water separation for bitumen produced by commercial steam-assisted gravity drainage (SAGD) occurs below critical dilution by water droplets' coalescence. When conducted close to critical dilution, the water separation process for SAGD-produced bitumen faces disruptions attributed to the partial suppression of coalescence and occurrence of agglomeration. In this study, asphaltene precipitation during water separation for SAGD bitumen is investigated with respect to paraffinic solvent addition by using flow-through apparatus for video recording and near-infrared (NIR) spectroscopy at process conditions. The thin liquid film (TLF) technique is employed to determine the effect of solvent-to-bitumen ratio on the properties of the contact zone between two adjacent water droplets in a continuous phase of diluted bitumen. The TLF results highlight changes in the contact zone properties indicative of asphaltene precipitation below the critical dilution detected by NIR spectroscopy. Asphaltene precipitation starts and increases gradually rather than abruptly, contrary to the conventional understanding of critical dilution. On the basis of these findings, it is proposed to consider asphaltene precipitation as a progression rather than a single onset. It is also proposed that the initial onset, termed a surface asphaltene precipitation onset, occurs below critical dilution and is followed by the initial bulk and massive bulk onsets, the latter being closest to critical dilution. The NIR technique effectively detects the initial and massive bulk onsets but cannot detect the surface onset due to observation wavelength limitations. These findings provide valuable insights and directions for addressing recurring issues in bitumen recovery, such as the perceived random occurrence of undesirable stable emulsions due to coalescence inhibition and ineffectiveness of additives in breaking these emulsions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Asphaltene Precipitation Onsets in Relation to the Critical Dilution of Athabasca Bitumen in Paraffinic Solvents

et al. 2022

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“…Partial upgrading has achieved great attention due to its low capital and operation cost, as well as potentiality to reduce the amount of diluents during the dilution process and avoid high-cost full upgrading . When the exploited heavy oil is presented as emulsions through hot water extraction or steam injection, further demulsification and water/oil separation are needed prior to partial upgrading . Ng and her research group have proposed a single-stage process coupling the emulsion separation and partial upgrading by capturing the highly active in situ hydrogen produced from the water–gas shift reaction (WGSR). − This novel process is of great interest for a more efficient and economical partial upgrading of heavy oil.…”

Section: Introductionmentioning

confidence: 99%

Structure–Solubility Relationship of CO Dispersion in Model Hydrocarbon Liquids and Heavy Oil Fractions

et al. 2021

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The solubility of CO in heavy oils is an important parameter for designing and optimizing the partial upgrading process of heavy oil under CO/syngas and water. To study the structure–solubility relationship of CO dispersion in organic liquids, the solubility of CO in hydrocarbons ( n -hexane, n -octane, n -hexadecane, cyclohexane, toluene, and 1-methylnaphthalene), petroleum distillates, and residues from Canadian oil sand bitumen was measured at different temperatures and pressures. The dispersion behavior of CO in different molecules was simulated by the molecular dynamics calculation. The role of water on CO dispersion in these systems was also explored. Experimental data show that the increase of both paraffinic chain length and aromaticity of molecules could hinder the dissolution of CO. By theoretical calculation, it is found that n -hexadecane and 1-methylnaphthalene present the strongest self-aggregation tendency, resulting in the low interaction with CO. The intermolecular forces of hydrocarbons appear to be the key factor determining the CO solubility. The dissolved H 2 O molecules could weaken the intermolecular forces of hydrocarbons and thus increase the CO solubility. Based on the model system study, the solubility of CO in complex petroleum distillates and heavy residues is rationalized by their molecular composition, which is mainly dependent on the relative proportion of paraffins to aromatics.

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Resourceful and harmless treatment of the steam-assisted gravity drainage produced fluid

Zhang,

Niu,

Shen

et al. 2024

Journal of Environmental Chemical Engineering

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Separation of SAGD produced emulsions through a combined pre-dewatering and demulsification process

Cited by 6 publications

References 21 publications

Asphaltene Precipitation Onsets in Relation to the Critical Dilution of Athabasca Bitumen in Paraffinic Solvents

Asphaltene Precipitation Onsets in Relation to the Critical Dilution of Athabasca Bitumen in Paraffinic Solvents

Structure–Solubility Relationship of CO Dispersion in Model Hydrocarbon Liquids and Heavy Oil Fractions

Resourceful and harmless treatment of the steam-assisted gravity drainage produced fluid

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