Hydroxypropyl Guar Gum Research Articles

Preparation and characterization of high-stability gel foam for fracture plugging in reservoirs

A high-stability gel foam is successfully prepared by forming a gel structure in the liquid film using polymer and crosslinker. The foaming properties, gel characteristics, foam stability, and microstructure of the high-stability gel foam are systematically studied. Although increasing the viscosity of the liquid film reduces the foam volume, it significantly enhances the foam stability. Considering the foaming properties, gel characteristics, and economic benefits, the optimal formulation of the gel foam system is determined to be 0.8% surfactant, 0.3% hydroxypropyl guar gum (HPG), and 0.2% organic titanium crosslinker (ATC). Microstructural analysis revealed that, compared to water-based and polymer foams, gel foam has smaller bubble sizes, lower drainage rates, and slower coarsening rates. This improvement is mainly attributed to the increased viscosity and thickness of the liquid film after gel and the formation of a three-dimensional network structure. Water loss rate experiment shows that the foam stability is stronger when the liquid film has certain viscosity and elasticity to resist external disturbances. However, higher viscosity and film strength do not necessarily result in better foam stability. The final water loss rate of the gel foam after being placed at 100 °C for 10 h is 74.45%, much lower than that of other higher-strength gel foams (greater than 99%). Fracture plugging experiments demonstrated that the plugging rate of gel foam is high (80%), whereas water-based foam achieved only 37.5%. The gel foam can effectively plug fractures and expand the swept volume, showing great potential for improving oil reservoir recovery.

Investigations of thermochemical fluids as cleanup system for polymer-based fracturing fluids

The cleanup of fracturing fluids, involving polymer degradation and well flowback, is crucial for the success of the fracturing operations and revenue generation. Breakers, such as oxidizers and enzymes, are commonly employed to break down polymers, resulting in lower viscosity, improved flowback, and facilitated well cleanup. However, these conventional breakers, which contribute solely to the cleanup process through polymer degradation, have some drawbacks, such as premature breaking and insufficient release of breakers. In this study, thermochemical fluids (TCFs) are proposed as a cleanup system. This system can improve the cleanup process by lowering viscosity through temperature increase and thermal degradation of polymers, reducing hydrostatic pressure via gas generation, and eliminating phase trapping damage in tight reservoirs through the heat produced. The TCFs investigated in this study were NH4Cl and NaNO2 solutions, where a substantial amount of heat was determined from the thermal energy study using an autoclave reactor. In this study, the thermal degradation of guar gum (GG) polymer derivatives, hydroxypropyl guar gum (HPG), and carboxymethyl hydroxypropyl guar gum (CMHPG) were assessed using Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), viscosity measurements, and coreflood experiments. Both FTIR and TGA analyses of linear gels of GG and its derivatives confirmed alterations in the chemical and thermal properties of these polymers following thermal treatments. The coreflood results showed a regained permeability of 87% for thermally treated HPG borate-crosslinked, 96% for CMHPG dual crosslinked (borate and zirconate), and 90% for slickwater fracturing fluids, respectively. The regained permeability of thermally treated slickwater was even better than that for slickwater with ammonium persulfate breaker.

Quantitative characterization of the crosslinking degree of hydroxypropyl guar gum fracturing fluid by low-field NMR

As a widely used water-based fracturing fluid, the performance of hydroxypropyl guar gum fracturing fluid is closely related to the degree of crosslinking, the quantitative characterization of which can reveal a detailed crosslinking mechanism and guide the preparation of fracturing fluid gels with an excellent performance. However, the commonly used high-temperature rheology method for evaluating the performance of fracturing fluids only qualitatively reflects the degree of crosslinking. In this study, low-field nuclear magnetic resonance (LF-NMR) was used to characterize the degree of crosslinking in guar gum fracturing fluid gels. The spin-spin relaxation time of the H proton in guar gum was molecularly analyzed using LF-NMR. The viscoelastic properties met the requirements when the crosslinking degree of the gel was 88–94 %. The transformation of the linear structure into a membrane structure during the crosslinking process of the guar gum fracturing fluid was confirmed by freeze-drying and scanning electron microscopy (SEM) from a microscopic perspective. The changing trend of the microstructure and viscoelastic properties of the fracturing fluid gel under different crosslinker dosages was consistent with changes in the degree of crosslinking. The LF-NMR test process is non-destructive to the gel structure, and the test results demonstrate good accuracy and repeatability.

Preparation and performance analysis of nano‐crosslinking agent for sulphonated guar gum fracturing fluid

AbstractIn order to solve the problems of poor temperature resistance and low crosslinking efficiency of crosslinking agent for sulphonated guar gum fracturing fluid, in this paper, nano‐silica was reacted with 3‐aminopropyltriethoxysilane to obtain surface‐modified nano‐silica, which was then reacted with boric acid and n‐butyl titanate to obtain nano‐silica‐based boron‐titanium composite crosslinking agent. Its physical properties and structure were characterized by infrared (IR), laser particle size analysis, X‐ray diffraction (XRD), and atomic force microscopy (AFM). The sulphonated hydroxypropyl guar gum fracturing fluids formed by nano‐crosslinking agent were analyzed: When the temperature was uniformly increased from 25 to 120°C and the shear rate was 170 s−1, the viscosity was finally constant at about 50 mPa · s, which indicated that the temperature and shear resistance were good; the system had a better filtration‐loss reduction performance; the average sedimentation rate of ceramic grains in the fracturing fluid system was 0.00872 cm · min−1, indicating that the system had good sand carrying performance; the damage rate of fracturing fluid filtrate to the core was 23.33%; the gel breaking performance test showed that the fracturing fluid had good gel breaking performance. By analyzing the performance of the fracturing fluid, it can be seen that the nano‐crosslinking agent has the advantages of good temperature resistance and high cross‐linking efficiency compared with the traditional boron and titanium cross‐linking agents.

LNMR analysis of the retention of different guar gum structure in sandstone: Based on a new characterization method

The adsorption and retention damage of guar gum to reservoirs are important factors affecting the effectiveness of hydraulic fracturing. Accurately understanding and evaluating the adsorption and retention of guar gum can better support the research of low-damage fracturing fluid. However, previous indoor evaluation methods have some limitations in studying the adsorption and retention characteristics of guar gum. The analysis object of low-field nuclear magnetic resonance (LNMR) is water rather than guar gum, which cannot achieve visualization of guar gum retention. In addition, Ordinary guar gum (GG), hydroxypropyl guar gum (HPG), and carboxymethyl guar gum (CMG) are commonly used in the hydraulic fracturing of sandstone gas reservoirs, but there are very few studies that focus on the differences in the adsorption and retention damage of the three guar gums from a microscopic perspective. In this study, a new characterization method for evaluating the retention of polymer in fracturing fluid based on the principles and properties of LNMR was proposed. This method can quantitatively evaluate the amount of guar gum adsorption retention and achieve a visual evaluation of the adsorption and retention of guar gum in cores. The aggregation characteristics of guar gum in porous media can be reflected. The dynamic retention process of GG, HPG, and CMG in sandstone cores was directly characterized through this method. The aggregation and entanglement characteristics of the three types of guar gum in sandstone were analyzed from the structure of guar gum. The experimental results show that the difference in molecular weight and modified groups of guar gum has an impact on its adsorption and retention. The molecular chain after the gel-breaking of GG was longer due to the large molecular weight. Long chains and intramolecular hydrogen bonds caused a larger curling degree of GG molecules. The entanglement degree of guar gum increased due to the introduction of non-ionic long-chain hydroxypropyl. The introduction of anionic carboxymethyl made CMG molecules more stretched due to electrostatic repulsion. The median particle size of the gel breaking liquid of GG was 10.65 μm, HPG was 8.8 μm, and CMG was 5.88 μm. A larger molecular particle size after guar gum gel breaking would aggravate the retention in sandstone porous media. After 150 min of displacement, the adsorption and retention amount of GG in the core was 4.59 mg/g, HPG was 4.17 mg/g, and CMG was 3.86 mg/g. The compactness of aggregates formed by guar gum in the core was HPG > GG > CMG. The gas flooding can relieve the adsorption and retention of guar gum. The higher the degree of entanglement of guar gum molecules, the more difficult to remove them from the core. The flowback degree of gas flooding of GG was 10.2%, HPG was 6.8%, and CMG was 21.9%. This research provides an experimental strategy for the microscopic evaluation of polymer adsorption and retention in rock porous media. The research results provide a deep understanding of the microscopic characteristics of guar gum adsorption and retention from the perspective of guar gum structure, which has some significance for guiding the optimization of fracturing fluid and the study of low-damage fracturing fluid.

Synergism of polysaccharide polymers in antihistamine eye drops: Influence on physicochemical properties and in vivo efficacy

The incorporation of polymers into drug delivery vehicles has been shown to be a useful approach to prolong the residence time of drugs in the precorneal tear film and to improve penetration into biological membranes. The main objective of this research was to formulate novel viscous eye drops with ketotifen as the active ingredient, containing the polysaccharides: chitosan (MCH), hydroxypropyl guar gum (HPG) and hyaluronic acid (SH) alone and in combination as functional polymers. DSC and FT-IR techniques showed the compatibility between ketotifen and polymers. Physicochemical and rheological analysis at ambient and simulated physiological conditions, as well as the evaluation of mucoadhesive properties showed that vehicles containing combinations of polymers have suitable physicochemical and functional properties with demonstrated synergism between combined polymers (MCH and HPG i.e. SH and HPG). The drug permeability was successfully estimated in vitro using HCE-T cell-based models. MTT cytotoxicity assay demonstrates that the tested formulations were non-toxic and well tolerated. In vivo preclinical study on mice revealed that both vehicles containing mixed polymers enhanced and prolonged the antipruritic/analgesic-like effect of ophthalmic ketotifen. Based on these results, both combinations of polysaccharide polymers, especially SH-HPG, could be considered as potential new carriers for ketotifen for ophthalmic use.

Starch microsphere silicon-boron crosslinker for low concentration hydroxypropyl guar gum based fracturing fluid

Hydroxypropyl guar gum (HPG) is a critical thickener to increase viscosity and lubrication to improve the water-based hydraulic fracturing efficiency. However, current crosslinkers require a large amount of HPG (>0.3 wt%) to form gel with sufficient viscosity, and high concentrations of HPG may cause adverse effects to the production and the environment. In this study, a novel starch microsphere silica‑boron crosslinker (SMSB) was developed using starch microspheres as a carrier and γ-aminopropyl triethoxy silane (KH550) as a modifier with an in-house method. Both the rheology and surface reactions of the SMSB-HPG crosslinking system were studied using multiple laboratory experiments and molecular dynamics simulation. The results showed that SMSB crosslinker caused multi-site cross-linking with low concentration (only 0.2 wt%) of HPG molecules, reducing the twisting of single molecular chain in the crosslinking system, enhancing the cross-linking strength between molecular chains, and making HPG molecular chains stretcher in the aqueous solution. The apparent viscosity and viscoelasticity of the HPG system were substantially higher than the organoboron crosslinker, and the temperature resistance of the SMSB-HPG crosslinking system was up to 140 °C. This study provides an alternative green crosslinker for more sustainable industrial applications and provides theoretical basis for the modification of biomaterials.

Degradation of hydroxypropyl guar gum by dual oxidant system catalyzed by hydrotalcite supported zero-valent transition metal

Degradation of hydroxypropyl guar gum by dual oxidant system catalyzed by hydrotalcite supported zero-valent transition metal

Carboxymethyl hydroxypropyl guar gum physicochemical properties in dilute aqueous media

We investigate carboxymethyl hydroxypropyl guar gum (CMHPG) solution properties in water and NaCl, KCl, and CaCl2 aqueous solutions. The Huggins, Kraemer, and Rao models were applied by fitting specific and relative viscosity of CMHPG/water and CMHPG/salt/water to determine the intrinsic viscosity [η]. The Rao models yielded better results (R2 = 0.779–0.999) than Huggins and Kraemer equations. [η] decreased up to 84% in salt solution over the range 0.9–100 mM compared to water. Salt effects screened the CMHPG charged side groups chains leading to a compacted structure. In 0.9 mM NaCl(aq), the hydrodynamic coil radius (Rcoil) was 28% smaller and 45% smaller in 100 mM NaCl solution relative to water. Similar decreases were seen in KCl and CaCl2 solutions. KCl and CaCl2 were more effective than NaCl. CMHPG is salt-tolerant and shows comparatively less viscosity change than native guar gum, with modest reduced viscosity increases with CMHPG dilution at all salt concentrations. The electrostatic interactions were effective up to 100 mM salt. The activation energy of viscous flow for CMHPG solutions was computed and compared to measured xanthan gum and several literature values. These data show that the barrier to CMHPG flow is higher than for xanthan gum.

Study on the mechanism of polymer inhibiting purplish soil fugitive dust at macro–micro scale in Southwest China

Polymers with good adhesion properties are typically used as soil fugitive dust suppressants in infrastructure construction. This study investigates the dust suppression effect of hydroxypropyl guar gum (HPG), polyacrylamide (PAM), and starch (STA), as well as analyses their bonding mechanism on soil fugitive dust surface via laboratory experiments and molecular simulations. Laboratory test results indicate that the viscosity of HPG solution is the highest. At a mass concentration of 0.35 %, the maximum viscosity recorded is 288.5 mPa∙s, which is 44.8 and 264.08 mPa∙s higher than those of PAM and STA solutions, respectively. The wind-erosion resistance rate of soil fugitive dust samples treated with HPG is 98.63 %, which is 2.66 %, 3.51 %, and 30.43 % higher than those of PAM, STA, and water, respectively. The water-erosion rate of soil fugitive dust samples treated with HPG is only 2.06 %, which is 0.52 %, 1.05 %, and 12.11 % lower than those of PAM, STA, and water, respectively. HPG exhibits excellent cohesiveness and effectively inhibits the generation of soil fugitive dust. Molecular simulation results show that the adsorption energy of HPG is 4.8 %–48.3 % and 3.2 %–54.8 % lower than those of PAM and STA, respectively, thus indicating the higher adsorption capacity of HPG. The distribution of HPG on the surface of soil fugitive dust components is the most concentrated. The self-diffusion coefficient of HPG is 0.3–6.7 and 1.2–12.4 times lower than those of PAM and STA, respectively; therefore, the structures of the HPG/soil fugitive dust component simulation systems are more stable. The radial distribution function shows that the van der Waals force is the primary force affecting the molecular dynamics behaviour, which signifies physical adsorption. The binding mechanism of polymers on the surface of soil fugitive dust is that the polymer approaches the surface of soil fugitive dust through van der Waals forces and eventually adsorbs onto the surface of soil fugitive dust to bond with it. This study provides a theoretical foundation for the development of more effective soil fugitive dust suppressants for infrastructure construction.

Degradation of oil filed pollutants by hydrogen peroxide and persulfate activated over zero-valent metal

Nano zero-valent metal were prepared to activate hydrogen peroxide (HP) and persulfate (PS) for efficient degradation of hydroxypropyl guar gum (HPG) in oilfield water to avoid secondary contamination caused by transition metal ions in the homogeneous reaction. The effects of H2O2/Na2S2O8 concentration, catalyst concentration, temperature and pH on the degradation rate of HPG were comprehensively evaluated in this study. It was found that Cu0 coupled with HP or PS provided an effective treatment pathway which was based on rapid Cu0-mediated decomposition of the oxidants, resulting in complete removals by decreasing the (chemical oxygen demand) COD from 7350 mg/L to 360 mg/L, in particular when PS was employed as the oxidant. The HPG degradation rate was 81% at 45 ℃, pH 7, oxidant ratio of 2:3 (H2O2:Na2S2O8), total oxidant dosage of 10% and Cu0 dosage of 0.3 g/L. The results of this study demonstrated that the combined degradation of HPG pollutants by Cu0-activated H2O2/Na2S2O8 has a wide range of applications which provides new strategies and mechanism insights for advanced oxidation of oilfield pollutants.

A fully biobased tough hydrogel derived from guar gum and gelatin as a flexible sensor

A fully natural polymer-based tough DN hydrogel (stretchability of 497%, stress of 0.44 MPa) was prepared using oxidized hydroxypropyl guar gum and gelatin though dynamic Schiff base bonds.

Low-temperature gel breaking fracturing fluid for marine hydrate reservoir fracturing and its effect on phase equilibrium of methane hydrates

Hydraulic fracturing has been proven useful for improving the gas production efficiency of low-permeability hydrate reservoirs. However, no specific fracturing fluid system exists for marine hydrate reservoirs. Applying conventional water-based fracturing fluids in low-temperature (<293.2 K) marine hydrate reservoirs can lead to difficulties in gel-breaking and hydrate instability caused by external additives. In this study, we developed two water-based fracturing fluid systems that exhibited good gel-breaking performance at low temperatures (278.2–288.2 K), one comprising ammonium persulfate (APS), ferrous sulfate (FeSO4), and citric acid (CA), the other APS and triethanolamine (TEA). In addition, we investigated the influence of crosslinking and gel-breaking reactions of the fracturing fluids on the methane hydrate phase equilibrium. The breaking time of the APS-FeSO4-CA system at 278.2K, 283.2K, and 288.2K was 30 min, 75 min, and 120 min respectively. On the other hand, the APS-TEA system accomplished the same task in 3 h, 6 h, and 10 h respectively. Furthermore, methane hydrate phase-equilibrium data showed that the fracturing fluid's three states, base fluid (BF), fracturing fluid gel (FFG), and gel-breaking liquid (GBL), all exerted an inhibitory effect on the phase equilibrium, with the hydrate suppression temperature (ΔT) ranging from 0.4 to 1.0 K. The differences in their inhibitory effect were primarily related to the micromorphology of the hydroxypropyl guar gum (HPG) molecules and the number of active hydroxyl (-OH) groups in the solution. Cryo-scanning electron microscopy (SEM) measurements revealed that the micromorphology of HPG in BF, FFG, and GBL transformed from regular ribbon-like structures to 3-D network structures and then to hole-containing, short ribbon-like structures. FFG formed a regular 3-D network structure after adding crosslinking agents to the BF. The ΔT values reversed from FFG < BF to FFG > BF when the HPG concentration increased from 0.3 wt% to 0.5 wt%, possibly due to the difference in the HPG molecules' water adsorption capacity before and after crosslinking. The broken HPG molecules with OH− groups in the solution were transformed into residues after gel-breaking, decreasing the GBL's inhibitory effect. Therefore, our results indicated that micromorphology variations could cause differences in the HPG molecules' water adsorption capacity, ultimately leading to ΔT differences. Based on our findings, the gel-breaking fracturing fluid systems we developed demonstrated potential for optimizing hydraulic fracturing in marine hydrate reservoirs.

A Comparative Study on Optimization of Reaction Conditions towards Synthesis of Hydroxypropyl Guar Gum with Higher Viscosity and Hydroxypropyl Content: A Statistical Approach

A Comparative Study on Optimization of Reaction Conditions towards Synthesis of Hydroxypropyl Guar Gum with Higher Viscosity and Hydroxypropyl Content: A Statistical Approach

High Efficient Degradation of Oilfield Waste Water Containing Polymers By Metal-tartaric Complex

This To provide an efficient catalyst for Fenton oxidation processing to the treatment in waste fracturing fluid containing hydroxypropyl guar gum under high pH value, a series of metal-tartaric acid complex was prepared for catalyzing the Fenton oxidation. The results show that Fe(III)L complex demonstrate high catalytic performance for degradation of polymer in a wide pH range from 8.0 to 12.0. The viscosity of hydroxypropyl guar gum can be reduced effectively to 2.3 after adding 10.0% H2O2 (mass ratio to hydroxypropyl guar gum) and using 10.0% Fe(III)L (mass ratio to H2O2) as catalysts. The COD value of the treated hydroxypropyl guar gum solution can be decreased to 107 mg/L from 8680 mg/L. The proposed mechanism of the activation of H2O2 by the complex was studied by UV spectrum.

Multifunctional Borax Cross-Linked Hydroxypropyl Guar Gum Hydrogels with Crop Nutritional Function as Carriers for Dual-Responsive Acaricide Release.

Hydrogels with porous networks have received considerable attention in smart pesticide delivery due to their inherent versatility. In this study, acaricide cyetpyrafen (CPF)-loaded borax (BO) cross-linked hydroxypropyl guar gum (HPG) (CPF@BO-co-HPG, CBG) hydrogels were prepared by cross-linking and pesticide loading simultaneously. The flowable CBG hydrogels with 3D porous network structures had better wetting and spreading ability on Citrus reticulata Blanco leaves and a hydrophobic interface. The nonflowable CBG hydrogels had pH- and temperature-responsive release properties. Meanwhile, the acaricidal efficacy of CBG against Panonychus citri (McGregor) at both 24 and 48 h was significantly higher than those of CPF-loaded BO-free HPG hydrogels. Furthermore, CBG had a nutritional function for cotton growth and environmental safety for zebrafish. This research developed a BO cross-linked HPG hydrogel as a smart pesticide delivery vehicle and crop nutrient replenishment, which can be widely applied in sustainable agriculture.

Catalytic Oxidation of Hydroxypropyl Guargum by a Fenton-like reaction

To seek for efficient Fenton-like oxidation processing for the treatment in waste fracturing fluid containing hydroxypropyl guargum under high pH value, a series of o-phenylenediamine(L) metal complex was prepared for the oxidation catalysts. The catalyst was screened by the viscosity reduction of hydroxypropyl guargum solution oxidized by H2O2. The results show that Fe (III)L exhibits high catalytic perform for degradation of hydroxypropyl guargum in a wide pH range 7.0-13.0. The viscosity of hydroxypropyl guar gum can be reduced effectively with the 10.0% H2O2 (mass ratio to hydroxypropyl guar gum) and 10.0% Fe (III)L (mass ratio to H2O2), and the COD value can be decreased to 630 mg/L from 7880 mg/L with enough H2O2, and Fe(III)L also shows great catalytic ability in the degradation of various polymers by H2O2. The proposed mechanism of the activation of H2O2 by the complex was studied by UV spectrum.

Effect of inorganic salts in coal seams on the sand-carrying capacity of hydroxypropyl guar foam-fracturing fluid: An experimental study

Coal seam water typically contains inorganic salts, which could affect the sand-carrying capacity of foam-fracturing fluid. This study selected the standard cationic surfactant cetyltrimethylammonium bromide as the foaming agent, used the high molecular polymer hydroxypropyl guar gum as the foam stabilizer to prepare foam-fracturing fluid, and selected silica particles as the proppant. The effects of different CaCl2, NaHCO3, MgSO4, and KCl concentrations on sand-carrying sedimentation of foam-fracturing fluid were evaluated. The effects of inorganic salts on foam morphology and foam morphology on proppant sedimentation were obtained through microscope observation, and the mechanism of inorganic salts on proppant sedimentation in foam-fracturing fluids was explored. The results show that 1% CaCl2 and 0.1% NaHCO3 inhibited the sand-carrying capacity of the foam-fracturing fluid, whereas two concentrations of MgSO4 and KCl promote the sand-carrying capacity of the foam-fracturing fluid. The effect of inorganic salts on the sand-carrying properties of cationic surfactant foam-fracturing fluids is divided into two main stages. During the settling phase, inorganic salts affect settling by changing the viscosity of the foam-fracturing fluid and the repulsive force of the double electric layer on the proppant. During the suspension phase, the proppant improves the probability of collision between the proppant and the foam by promoting the foam particle size and improves the hindering effect of foam pressure and structural forces on the proppant. The results have a guiding significance for developing foam-fracturing technology.

A Study on the Stability and Antimicrobial Efficacy of a Newly Modeled Teat Dip Solution Containing Chlorhexidine.

Despite much focus on mastitis as an endemic disease, clinical and subclinical mastitis remains an important problem for many herds. Reducing the usage of antibiotics for mastitis treatment allows the risks to be minimized related to the development of antimicrobial resistance and the excretion of antibiotics into the environment. The aim of the study was to determine the physico-chemical properties, stability and antimicrobial effect of a newly formulated biocide for post-milking udder hygiene containing a thickener made from hydroxypropyl guar gum, an antiseptic chlorhexidine digluconate and teat skin-friendly components including glycerol, Mentha Arvensis herbal oil and Aesculus hippocastanum extract. Hydroxypropyl guar gum was used as a thickener to provide the physical parameters and to retain the viscosity at 1438 mPa.s. The physical and chemical properties of the product, including the 12-month stability, were tested in long-term and accelerated stability studies. The product was effective against the primary mastitis pathogens, including Staphylococcus aureus, Streptococcus uberis, Escherichia coli, Candida albicans and Aspergillus niger.

Mechanism analysis of enhancing the temperature and shear resistance of hydroxypropyl guar gum fracturing fluid by boron-functionalized nanosilica colloidal crosslinker

With the increasing depth of reservoir development, the temperature and shear resistance of fracturing fluids needs to be further improved. In comparison with traditional crosslinking agents, nano-crosslinkers have superior crosslinking properties and can enhance the temperature and shear resistance of fracturing fluids. However, the synthesis of nano-crosslinkers is complicated and not sufficiently explained to elucidate the crosslinking mechanism. In this study, a nanosilica colloidal crosslinker with a larger size and more crosslinking sites was synthesized by a simplified method using nanosilica. The structure and crosslinking mechanism of nanosilica crosslinkers were explored using FTIR, XPS, TGA, and SEM. The results indicated that the nanosilica and organoboron were bonded through B-N bonds. The nanosilica crosslinker has good dispersion and excellent thermal stability. The thermal and shear stability of nano-crosslinked fracturing fluids was better than that of fracturing fluids formed with organoboron crosslinkers. Specifically, temperature resistance is enhanced by 7–18 °C and shear resistance by 5–20 mPa s. In addition, the gel-breaking fluid changes the wettability of the core surface and enhances the flow capacity of the oil. The results of FTIR showed the synergistic effect of hydrogen and covalent bonding between the crosslinker and guar gum molecules. The results of SEM indicated that the guar gum molecules are transformed from a linear structure to a membrane structure during the transformation of the fracturing fluid from a base fluid to a gel, which gave the gel water retention capacity and good proppant-carrying capacity. Furthermore, the nanosilica crosslinker is distributed on the surface of the membrane or located in the membrane by binding to the membrane. The interaction between the nanoparticles and the membrane structure enhances the strength of the membrane structure, which allows for better shear stability of the nano-crosslinked fracturing fluid at high temperatures.