Silica Nanoparticles in Xanthan Gum Solutions: Oil Recovery Efficiency in Core Flooding Tests

Polymer flooding is one of the enhanced oil recovery (EOR) methods that increase the macroscopic efficiency of the flooding process and enhanced crude oil recovery. In this study, the effect of silica nanoparticles (NP-SiO₂) in xanthan gum (XG) solutions was investigated through the analysis of efficiency in core flooding tests. First, the viscosity profiles of two polymer solutions, XG biopolymer and synthetic hydrolyzed polyacrylamide (HPAM) polymer, were characterized individually through rheological measurements, with and without salt (NaCl). Both polymer solutions were found suitable for oil recovery at limited temperatures and salinities. Then, nanofluids composed of XG and dispersed NP-SiO₂ were studied through rheological tests. The addition of nanoparticles was shown to produce a slight effect on the viscosity of the fluids, which was more remarkable over time. Interfacial tension tests were measured in water-mineral oil systems, without finding an effect on the interfacial properties with the addition of polymer or nanoparticles in the aqueous phase. Finally, three core flooding experiments were conducted using sandstone core plugs and mineral oil. The polymers solutions (XG and HPAM) with 3% NaCl recovered 6.6% and 7.5% of the residual oil from the core, respectively. In contrast, the nanofluid formulation recovered about 13% of the residual oil, which was almost double that of the original XG solution. The nanofluid was therefore more effective at boosting oil recovery in the sandstone core.

Effect of Silica Nanoparticles in Xanthan Gum Solutions: Evolution of Viscosity over Time

The effect of silica nanoparticles (NP-SiO₂) in xanthan gum (XG) solutions was investigated through the analysis of viscosity profiles. First, hydrocolloid XG solutions and hydrophilic NP-SiO₂ suspensions were characterized individually through rheological measurements, with and without salt (NaCl). Then, nanofluids composed of XG and NP-SiO₂ dispersed in water and brine were studied through two different aging tests. The addition of nanoparticles was shown to produce a slight effect on the viscosity of the fresh fluids (initial time), while a more remarkable effect was observed over time. In particular, it appears that the presence of NP-SiO₂ stabilizes the polymer solution by maintaining its viscosity level in time, due to a delay in the movement of the molecule. Finally, characterization techniques such as confocal microscopy, capillary rheometry, and Zeta potential were implemented to analyze the XG/NP-SiO₂ interaction. Intrinsic viscosity and relative viscosity were calculated to understand the molecular interactions. The presence of NP-SiO₂ increases the hydrodynamic radius of the polymer, indicating attractive forces between these two components. Furthermore, dispersion of the nanoparticles in the polymeric solutions leads to aggregates of an average size smaller than 300 nm with a good colloidal stability due to the electrostatic attraction between XG and NP-SIO₂. This study proves the existence of interactions between XG and NP-SiO₂ in solution.

Evaluation of Polymeric Materials for Chemical Enhanced Oil Recovery

Polymer flooding is a promising enhanced oil recovery (EOR) technique; sweeping a reservoir with a dilute polymer solution can significantly improve the overall oil recovery. In this overview, polymeric materials for enhanced oil recovery are described in general terms, with specific emphasis on desirable characteristics for the application. Application-specific properties should be considered when selecting or developing polymers for enhanced oil recovery and should be carefully evaluated. Characterization techniques should be informed by current best practices; several are described herein. Evaluation of fundamental polymer properties (including polymer composition, microstructure, and molecular weight averages); resistance to shear/thermal/chemical degradation; and salinity/hardness compatibility are discussed. Finally, evaluation techniques to establish the polymer flooding performance of candidate EOR materials are described.

A zwitterionic polymer containing a hydrophobic group: enhanced rheological properties

A zwitterionic polymer containing a hydrophobic long chain, named MANPS, was independently developed by free radical solution polymerization.

Synthesis of acryloylated starch-g-poly acrylates crosslinked polymer functionalized by emulsified vinyltrimethylsilane derivative as a novel EOR agent for severe polymer flooding strategy

Starch is a natural polysaccharide with reasonable biodegradable properties, which grafted with vinyl monomers through different initiators to be applied in enhanced oil recovery (EOR) techniques. Several authors stated about starch modification through copolymerization and grafting of different monomers, however, these derivatives have some drawbacks related to bacterial biodegradation, ionic and thermal aging under severe reservoir conditions. The present study reported the preparation of grafted acryloylated starch with acrylamide/acrylic acid monomers and vinyltrimethylsilane through initiation copolymerization with the aid of quaternary ammonium-based surfmer. The chemical analysis generated by various spectroscopic analysis comprising IR, NMR, meanwhile particles distribution estimated through DLS. The embedded silica through a polymer matrix photographed by TEM, SEM and EDX elementary analysis, and the thermal effect determined by thermal gravimetric analysis. The rheological analysis estimated relative to shear degradation, ionic strength, and thermal aging at imitated reservoir environment. Flooding runs performed on linear non-consolidated sandstone model at nearly practical field conditions, where the displaced oil by polymer effect was recorded through the volumetric collector. The flooding tests designate that the synthesized starch-g-copolymer is prospering for chemical flooding applications under severe reservoir conditions, and achieve a recovery factor of 46% S_or.

Comb-shaped polyzwitterion with surface-activity obtained via N-maleoyl chitosan-modified HPAM for displacement of residual oil

Comb-shaped polyzwitterions with surface-activity were successfully synthesized and displayed superior rheological properties to enhance the displacement of residual oil.

A novel α-aminophosphonic acid-modified acrylamide-based hydrophobic associating copolymer with superb water solubility for enhanced oil recovery

Here we report a novel α-aminophosphonic acid-modified acrylamide-based hydrophobic associating copolymer. The copolymer exhibits significant potential as an enhanced oil recovery chemical for high-temperature and high-mineralization oilfields.

Semi fluorinated polymers as surface energy controlled layers for liquid crystal alignment

The effects of compounded hydrogenated–fluorinated surfaces formed by perfluorocyclobutane (PFCB)-containing polymers on the alignment of a liquid crystal, 4,4′-octylcycanobiphenyl (8CB), were investigated.

Investigation of Optimum Polymerization Conditions for Synthesis of Cross-Linked Polyacrylamide-Amphoteric Surfmer Nanocomposites for Polymer Flooding in Sandstone Reservoirs

Currently enhanced oil recovery (EOR) technology is getting more attention by many countries since energy crises are getting worse and frightening. Polymer flooding by hydrophobically associated polyacrylamides (HAPAM) and its modified silica nanocomposite are a widely implemented technique through enhanced oil recovery (EOR) technology. This polymers class can be synthesized by copolymerization of acrylamide (AM), reactive surfmer, functionalized silica nanoparticles, and a hydrophobic cross-linker moiety in the presence of water soluble initiator via heterogeneous emulsion polymerization technique, to form latexes that can be applied during polymer flooding. Chemical structure of the prepared copolymers was proven through different techniques such as Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic spectroscopy (1H&13C-NMR), and molecular weight was measured by gel permeation chromatography. Study of the effects of monomer, surfmer, cross-linker, silica, and initiator concentrations as well as reaction temperature was investigated to determine optimum polymerization conditions through single factor and orthogonal experiments. Evaluation of the prepared copolymers for enhancing recovered oil amount was evaluated by carrying out flooding experiments on one-dimensional sandstone model to determine recovery factor.

A novel water-soluble hydrophobically associating polyacrylamide based on oleic imidazoline and sulfonate for enhanced oil recovery

We report here a novel imidazoline functionalized hydrophobically associating copolymer that exhibits excellent rheological properties and outstanding potential for enhanced oil recovery.

An anti-biodegradable hydrophobic sulfonate-based acrylamide copolymer containing 2,4-dichlorophenoxy for enhanced oil recovery

We report the synthesis of a novel hydrophobic sulfonate-based acrylamide copolymer which exhibits remarkable water solubility, excellent resistance to biodegradability, and superior ability to enhance oil recovery.

Morita-Baylis-Hillman reaction of acrylamide with isatin derivatives

The Morita–Baylis–Hillman reaction of acrylamide, as an activated alkene, has seen little development due to its low reactivity. We have developed the reaction using isatin derivatives with acrylamide, DABCO as a promoter and phenol as an additive in acetonitrile. The corresponding aza version with acrylate and acrylonitrile has also been developed resulting in high product yields.