Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-Up
Studies of the effects produced by the solubilization of hydrophobic substances by micellar aggregates in water medium are quite important for applications of viscoelastic surfactant solutions for enhanced oil recovery (EOR), especially in hydraulic fracturing technology. The present paper aims at t...
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| Format: | Article |
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MDPI AG
2020-11-01
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| Series: | Nanomaterials |
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| Online Access: | https://www.mdpi.com/2079-4991/10/12/2353 |
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| author | Andrey V. Shibaev Anna L. Aleshina Natalya A. Arkharova Anton S. Orekhov Alexander I. Kuklin Olga E. Philippova |
| author_facet | Andrey V. Shibaev Anna L. Aleshina Natalya A. Arkharova Anton S. Orekhov Alexander I. Kuklin Olga E. Philippova |
| author_sort | Andrey V. Shibaev |
| collection | DOAJ |
| description | Studies of the effects produced by the solubilization of hydrophobic substances by micellar aggregates in water medium are quite important for applications of viscoelastic surfactant solutions for enhanced oil recovery (EOR), especially in hydraulic fracturing technology. The present paper aims at the investigation of the structural transformations produced by the absorption of an aliphatic hydrocarbon (n-decane) by mixed wormlike micelles of cationic (n-octyltrimethylammonium bromide, C8TAB) and anionic (potassium oleate) surfactants enriched by C8TAB. As a result of contact with a small amount (0.5 wt%) of oil, a highly viscoelastic fluid is transformed to a water-like liquid. By small-angle neutron scattering (SANS) combined with cryo-TEM, it was shown that this is due to the transition of long wormlike micelles with elliptical cross-sections to ellipsoidal microemulsion droplets. The non-spherical shape was attributed to partial segregation of longer- and shorter-tail surfactant molecules inside the surfactant monolayer, providing an optimum curvature for both of them. As a result, the long-chain surfactant could preferably be located in the flatter part of the aggregates and the short-chain surfactant—at the ellipsoid edges with higher curvature. It is proven that the transition proceeds via a co-existence of microemulsion droplets and wormlike micelles, and upon the increase of hydrocarbon content, the size and volume fraction of ellipsoidal microemulsion droplets increase. The internal structure of the droplets was revealed by contrast variation SANS, and it was shown that, despite the excess of the cationic surfactant, the radius of surfactant shell is controlled by the anionic surfactant with longer tail. These findings open a way for optimizing the performance of viscoelastic surfactant fluids by regulating both the mechanical properties of the fluids and their clean-up from the fracture induced by contact with hydrocarbons. |
| first_indexed | 2024-03-10T14:31:23Z |
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| id | doaj.art-bdd20263e4424033860d8011b8635b25 |
| institution | Directory Open Access Journal |
| issn | 2079-4991 |
| language | English |
| last_indexed | 2024-03-10T14:31:23Z |
| publishDate | 2020-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nanomaterials |
| spelling | doaj.art-bdd20263e4424033860d8011b8635b252023-11-20T22:32:43ZengMDPI AGNanomaterials2079-49912020-11-011012235310.3390/nano10122353Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-UpAndrey V. Shibaev0Anna L. Aleshina1Natalya A. Arkharova2Anton S. Orekhov3Alexander I. Kuklin4Olga E. Philippova5Physics Department, Lomonosov Moscow State University, 119991 Moscow, RussiaPhysics Department, Lomonosov Moscow State University, 119991 Moscow, RussiaA.V. Shubnikov Institute of Crystallography, 119333 Moscow, RussiaNational Research Centre “Kurchatov Institute”, 123182 Moscow, RussiaMoscow Institute of Physics and Technology, 141701 Dolgoprudny, RussiaPhysics Department, Lomonosov Moscow State University, 119991 Moscow, RussiaStudies of the effects produced by the solubilization of hydrophobic substances by micellar aggregates in water medium are quite important for applications of viscoelastic surfactant solutions for enhanced oil recovery (EOR), especially in hydraulic fracturing technology. The present paper aims at the investigation of the structural transformations produced by the absorption of an aliphatic hydrocarbon (n-decane) by mixed wormlike micelles of cationic (n-octyltrimethylammonium bromide, C8TAB) and anionic (potassium oleate) surfactants enriched by C8TAB. As a result of contact with a small amount (0.5 wt%) of oil, a highly viscoelastic fluid is transformed to a water-like liquid. By small-angle neutron scattering (SANS) combined with cryo-TEM, it was shown that this is due to the transition of long wormlike micelles with elliptical cross-sections to ellipsoidal microemulsion droplets. The non-spherical shape was attributed to partial segregation of longer- and shorter-tail surfactant molecules inside the surfactant monolayer, providing an optimum curvature for both of them. As a result, the long-chain surfactant could preferably be located in the flatter part of the aggregates and the short-chain surfactant—at the ellipsoid edges with higher curvature. It is proven that the transition proceeds via a co-existence of microemulsion droplets and wormlike micelles, and upon the increase of hydrocarbon content, the size and volume fraction of ellipsoidal microemulsion droplets increase. The internal structure of the droplets was revealed by contrast variation SANS, and it was shown that, despite the excess of the cationic surfactant, the radius of surfactant shell is controlled by the anionic surfactant with longer tail. These findings open a way for optimizing the performance of viscoelastic surfactant fluids by regulating both the mechanical properties of the fluids and their clean-up from the fracture induced by contact with hydrocarbons.https://www.mdpi.com/2079-4991/10/12/2353viscoelastic surfactant solutionswormlike surfactant micellesmicroemulsionenhanced oil recoveryhydraulic fracturing |
| spellingShingle | Andrey V. Shibaev Anna L. Aleshina Natalya A. Arkharova Anton S. Orekhov Alexander I. Kuklin Olga E. Philippova Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-Up Nanomaterials viscoelastic surfactant solutions wormlike surfactant micelles microemulsion enhanced oil recovery hydraulic fracturing |
| title | Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-Up |
| title_full | Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-Up |
| title_fullStr | Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-Up |
| title_full_unstemmed | Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-Up |
| title_short | Disruption of Cationic/Anionic Viscoelastic Surfactant Micellar Networks by Hydrocarbon as a Basis of Enhanced Fracturing Fluids Clean-Up |
| title_sort | disruption of cationic anionic viscoelastic surfactant micellar networks by hydrocarbon as a basis of enhanced fracturing fluids clean up |
| topic | viscoelastic surfactant solutions wormlike surfactant micelles microemulsion enhanced oil recovery hydraulic fracturing |
| url | https://www.mdpi.com/2079-4991/10/12/2353 |
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