Interaction of carboxylated polyacrylamide with chromium(III) acetate: 13C NMR study of mechanism

Krul, L. P.; Shakhno, A. V.; Grinyuk, E. V.; Скаковский, Е. Д.; Tychinskaya, L. Yu.; Gospodarev, D.A.; Makarevich, A. V.

doi:10.1134/s1070363213110091

Cited by 6 publications

(5 citation statements)

References 5 publications

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“…It is assumed that during the formation of a three-dimensional gel structure, the Cr 3+ cation preferentially binds with two carboxyl groups of neighboring HPAN macromolecules and two water molecules. A similar process is observed during the interaction of another polymer of the acrylic series-polyacrylamide (PA)-which also contains carboxyl groups in its macromolecule [12,21,22].…”

Section: Selection Of the Conqcentration Of Hydrolyzed Polyacrylonitrilementioning

confidence: 77%

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Surfactant–Polymer Composition for Selective Water Shut-Off in Production Wells

Magadova,

Silin,

Gubanov

et al. 2024

Gels

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Today, a significant part of production wells’ stock has a high water cut percentage of 90% and above. Obviously, for this reason, the need to develop new and improved existing technologies for water shut-off in wells increases every year. Physico-chemical methods of water shut-off are based on the application of special reagents and compositions that plug the pathways of water inflow to the well. Depending on the mechanism and specific features of water barrier formation, isolation methods are divided into selective and non-selective. This article investigates the possibility of using hydrolyzed polyacrylonitrile as a gel-forming and precipitation-forming reagent for water shut-off technologies in production wells. A surfactant–polymer composition for the isolation of water inflow in production wells in objects with high salinity in formation water, possessing physical and chemical selectivity and providing permeability reduction only in water-saturated intervals, is proposed. The developed composition is the invert emulsion, which makes it possible to carry out treatment at a distance from the well and solve the problem of possible premature gel formation directly in the wellbore. The lowest effective concentration of HPAN in an aqueous solution for use as a gel-forming and sedimentation reagent was determined experimentally (5.0 wt% and more). The interaction of the polymer solution with a chromium crosslinker allows obtaining structured gels in the whole volume of the system. The structure of the gels was evaluated using the Sydansk classifier with the assignment of a letter code from A to J. It was experimentally proved that the structure of the obtained gels depends on the temperature and content of the crosslinking agent in the system; the more crosslinking agent in the composition of the system, the stronger the structure of the resulting gel. The optimal ratio of polymer and crosslinking agent to obtain a strong gel was obtained, which amounted to 5:1 by weight of dry polymer powder. For the HPAN concentration of 5 wt% according to the Sydansk classifier, the gel structure had the code “H”—slightly deformable non-flowing gel. The dependence of the volume of gel sediment obtained because of the interaction with mineralized water on the polymer concentration was studied. It was proved that an increase in the concentration of hydrolyzed polyacrylonitrile in the solution, as well as an increase in the concentration of calcium ions in mineralized water, leads to a larger volume of the resulting gel or precipitate and to the strengthening of the gel structure. The results of rheological studies of the developed composition, as well as experiments on thermal stability, are presented. The results of filtration tests on bulk reservoir models demonstrated the selectivity of the developed composition. The obtained value of the residual resistance factor for the oil-saturated low-permeability model was 1.49 units; the value of the residual resistance factor for the water-saturated high-permeability model was 18.04 units. The ratio of the obtained values of the residual resistance factor, equal to 0.08 (much less than 1), can characterize the developed composition as a selective material for water shut-off in producing wells. Existing technologies for water shut-off based on HPAN do not allow for making a treatment at a distance from the well and require the use of technological solutions to prevent premature gel sedimentation in the well. The developed composition makes it possible to solve the problem of premature gelation. In addition, the composition can form a blocking screen in highly permeable water-saturated zones. The development can be useful for deposits with difficult conditions (high mineralization in reservoir waters, boreholes with a horizontal end, elevated temperatures up to 80 °C).

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Section: Selection Of the Conqcentration Of Hydrolyzed Polyacrylonitrilementioning

confidence: 77%

“…The chromium (III) cation is bonded to two carboxylate groups of the polymer and to two water molecules. In this case, carboxylate groups act as bidentate ligands [12]. Thus, carboxylate groups of HPAN play a crucial role in gel formation.…”

Section: Introductionmentioning

confidence: 99%

Surfactant–Polymer Composition for Selective Water Shut-Off in Production Wells

Magadova,

Silin,

Gubanov

et al. 2024

Gels

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“…The effect was attributed to possible additional cross-linking of macromolecules of the acrylamide-sodium acrylate copolymer via donoracceptor bonds between the metal ion and the oxygen atom of the carboxylate group [3]. Later, the formation of metal-polymer complexes was proved by 13 C NMR spectroscopy for copolymers of acrylamide with sodium acrylate even with a very low content of carboxylate groups (3 mol %) [7]. The additional cross-linking of PEHG with Cu 2+ ions, revealed in this study, apparently occurs via carboxylate groups.…”

Section: Resultsmentioning

confidence: 96%

Effect of Cu2+, Zn2+, and Mn2+ ions on the water absorption of polyelectrolyte hydrogels based on polyacrylonitrile fiber hydrolyzate

et al. 2014

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Polyelectrolyte hydrogels based on 40% aqueous-salt solutions of polyacrylonitrile fi ber hydrolyzate were prepared using products of thermal decomposition of ammonium persulfate as cross-linking agent. Swelling of these gels in aqueous solutions of zinc, copper, and manganese sulfates is followed by the inverse process leading to the collapse of the hydrogels. The use of complex salts of the above ions prevents the inverse process. The relationships characterizing the infl uence of the cross-linking agent concentration on the initial swelling rate and on the equilibrium and maximum swelling in distilled water and in 0.01 M solutions of copper sulfate and disodium copper ethylenediaminetetraacetate were determined.

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“…Klaveness et al [20] introduced the dynamic storage modulus, G , to study the gelation process mechanism, indicating that the observed biphasic natures of the first-order plots from rheology and spectroscopy measurements are due to a side reaction; the cross-linking can proceed through a rate-determining introduction of the first HPAM to Cr(III). Krul et al [21] used 13 C NMR to study the interaction of Cr(III)/HPAM gel, which showed that formation of the complex is a driving force of the interaction, the complex contains two or three carboxylate groups, and the amide units are not involved in any specific interaction with the cation. Jin et al [22] investigated the relationship between gelation performance and microstructures of Cr(III)/HPAM gel.…”

Section: Introductionmentioning

confidence: 99%

Macroscopic Profile Modification and Microscopic Displacement Mechanism of Weak Gel Flowing in Porous Media

Wang

Kang

Zhang

et al. 2016

Journal of Chemistry

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In this paper, the flowing mechanism and function on the macroscopic and microscopic scale in the porous media of a widely used weak gel of an acrylamide based polymer crosslinked with chromium(III) were studied. Innovative microscopic plane visualization model was designed for microscopic scale experiment and sand pack physical model for macroscopic scale. The microscopic displacing experiments indicate that weak gel mainly intrudes into big pores rather than small ones, which can improve the conformance horizontally and increase the sweep efficiency benefiting from fluid diversion. Additionally, due to good viscoelasticity of weak gel, the negative pressure effect was formed enhancing oil recovery flow from small pore throats. Results of macroscopic physical sand pack flow experiment indicate positive influence of weak gel on vertical conformance control. Although the high permeable layer was not completely blocked, the oil recovery improved as a result of weak gel movement by continuous water flooding. Experiments results lead to conclusion, the primary function of weak gel is oil displacement, profile modification is secondary, and its effect is temporary.

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Interaction of carboxylated polyacrylamide with chromium(III) acetate: 13C NMR study of mechanism

Cited by 6 publications

References 5 publications

Surfactant–Polymer Composition for Selective Water Shut-Off in Production Wells

Surfactant–Polymer Composition for Selective Water Shut-Off in Production Wells

Effect of Cu2+, Zn2+, and Mn2+ ions on the water absorption of polyelectrolyte hydrogels based on polyacrylonitrile fiber hydrolyzate

Macroscopic Profile Modification and Microscopic Displacement Mechanism of Weak Gel Flowing in Porous Media

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