Oil Interface Research Articles

Effects of pressure depletion rate, solvent, and surfactant on non‐equilibrium reactions in foamy oil

AbstractThis research employed a visual method to explore the behaviour of foamy oil in heavy oil systems. A Hele‐Shaw cell was designed for observing the volumetric expansion of foamy oil as the system pressure decreased. This approach facilitated an examination of foamy oil's interface evolution under pressure depletion and an analysis of bubble sizes and their distribution. Using Minitab, 15 experiments were strategized, aimed at observing the distribution of bubbles and their stability during the foamy oil process. The investigation also extended to studying the influence of surfactants, solvent type, and pressure reduction rate on foamy oil. The findings suggest that a high concentration of surfactant, a high percentage of CO2 solvent, and a rapid pressure drop rate all contributed to the generation of microbubbles and enhanced volumetric expansion and stability of foamy oil. However, in light of the conducted energy analysis, a lower rate of pressure reduction is recommended. Finally, the conditions of the 15 experiments were applied to the CMG to derive two non‐equilibrium reactions for bubble generation and collapsing. The reaction rates are such that they relate bubble generation to the pressure reduction rate of the process and bubble resistance to collapsing to the surfactant concentration of the foamy oil.

Bottlebrush Random Copolymers at Oil‐Oil Interfaces

Comprehensive SummaryOil‐in‐oil nonaqueous emulsions are of great interest for developing emulsion‐templated polymers and encapsulation systems that are incompatible with water‐sensitive substances. Tailor‐made amphiphilic block copolymers are by far the most efficient stabilizers for oil‐in‐oil emulsions while less attention is given to copolymers with more complex architectures. Here, we report the stabilization of DMSO‐silicone oil interface by bottlebrush random copolymers (BRCPs) containing norbornene backbones with densely grafted poly(methyl methacrylate) (PMMA) and polystyrene (PS) side chains. The assembly kinetics of BRCPs at the DMSO‐silicone oil interface can be divided into three processes, including diffusion, reconfiguration and reorganization, and can be varied by tuning the degree of polymerization of the backbone (NB). Due to the high efficiency of BRCPs in reducing the interfacial tension, when using BRCPs as stabilizers, stable silicone oil‐in‐DMSO traditional emulsions and high internal phase emulsions (HIPEs) can be successfully obtained, while no stable emulsions can be achieved with linear PMMA‐b‐PS serving as the stabilizer. This study, for the first time, underscores the great potential of amphiphilic bottlebrush copolymers in preparing oil‐in‐oil emulsions. Given the advances in polymerization strategy, a broad variety of amphiphilic bottlebrush copolymers are expected to be synthesized and applied in the stabilization of nonaqueous biphasic systems.

Reconfigurable All-Oil Microfluidic Devices by 3D Printing.

Nanoparticle surfactants have been widely used to construct structured liquids in oil-water systems. Less attention, though, has been given in non-aqueous systems, for example, oil-oil systems, mainly due to the lack of suitable surfactants. Here, by using newly developed molecular brush surfactants (MBSs) that form at the DMSO-silicone oil interface, the construction of all-oil microfluidic devices is reported with advanced functions. Due to the high interfacial activity of MBSs, Plateau-Rayleigh instabilities of liquid jets can be completely suppressed, leading to the production of liquid threads with jammed MBSs at the interface. Taking advantage of the 3D printing technique, all-oil microfluidic devices with complex structures can be constructed, showing promising applications in mass transmission, chemical separation, and material synthesis.

Visual study of hydrate particles agglomeration and rolling characteristic in gas-oil-water phase using a flow loop

Natural gas hydrate blockage always leads to safety problems in oil and gas transportation pipelines. It is important to look for the characteristic of hydrate blockage process. The hydrate blockage was visually investigated under gas-oil-water multi-phase flow conditions in a flow loop in this study. The change of pressure drop with water conversion rate variations were detected. The hydrate particle movements were also observed in the visual pipes at different liquid loadings and water cuts. It was found that the hydrate particles may agglomerate and deposit with an obvious rolling process in low water cut conditions. The oil phase will accelerate particles agglomeration in the contact interface of oil, gas and water, and form a large number of flocculent hydrates. A theoretical hydrate particle rolling model was conducted to analysis the experiment results, and the hydrate particle velocity increases first and then decreases with the increase of particle diameter due to the comprehensive influence of van der Waals force and drag force. The results also confirmed the maximum of the pressure drop increased when the liquid loading increased. However, the hydrate formation and blockage speed also slow down due to small component of the gas phase in high liquid loading. In addition, comparing with 20 % and 80 % water cut, 50 % water cut has the fastest hydrate formation speed in different experimental conditions. Furthermore, the maximum water conversion rate increased with have a higher water cut. More hydrate will form in the condition, which will lead to the decrease of flow velocity in the pipeline.

Online detection of mixed oil interface in multi-product pipeline using near-infrared spectroscopy

To ensure the quality of refined oil products of sequential transportation, it is necessary to monitor and judge the interfaces between pure oils and mixed oil for guiding accurate mixed oil cutting. In this study, near-infrared spectroscopy (NIRS) was used to investigate the change trend of oil concentration and thus judge the interfaces. The methods of standard deviation of continuous spectra, principal component analysis, difference spectrum, and vector angle θ were used to analyze the online oil NIR spectra to detect the interfaces, respectively. The results show that θ of the spectra pretreated by the combination of airPLS and 1st derivative is the best for reflecting the concentration change trend of mixed oil and judging the interfaces. The interface between the forward pure oil and mixed oil can be judged by a fixed θ threshold, and the interface between the rear pure oil and mixed oil can be judged by a fixed first-order derivative value of the five-parameter logistic fitted curve of θ. This method is not affected by the interference and oil composition change of different batches and does not require oil properties and pipeline parameters, thus it has a good prospect in the oil pipeline transportation field.

Artificial neural network framework for the selection of deep eutectic solvents promoted enhanced oil recovery by interfacial tension reduction mechanism

Estimation of interfacial tension (IFT) and % reduction in IFT of Brazil and China regions’ heavy crude oil is employed by Artificial Intelligence (AI) led frameworks. The uniqueness of proposed approach lies in using AI frameworks that are constructed using Artificial Neural Network (ANN) and meta-heuristic algorithms i.e. Genetic Algorithm (GA) and Grey Wolf Optimization (GWO) forms three AI frameworks namely ANN, ANN-GA, and ANN-GWO is employed for IFT estimation of heavy oil and deep eutectic solvent-brine interface. The hyper-parameters of the frameworks are trained, validated, and tested over 18228 IFT data points obtained from the Omani heavy crude oil. The intermolecular interactions between oil, brine, and DES are obtained by generating surface segments in COnductor like Screening MOdel for Real Solvent (COSMO-RS) framework. The composition of brine, mole ratio of oil, DES, and temperature are other input parameters for AI model. The IFT estimation leads to the selection of 3 hydrophilic DESs capable of greater than 75 % IFT reduction and 14 hydrophilic DESs capable of 50–75 % IFT reduction. ANN-GWO scores best AI framework among 3 whereas ANN-GA fails to estimate IFT reduction greater than 50 %. Analysis of IFT with respect to mole fraction reveals the most suitable range of DES addition for IFT reduction.

Multifunctional ceramifiable silicone foam for smart fire fighting

The development of multifunctional silicone foam with high fire safety is of great significance to realize intelligent fire protection but challenging. Herein, a multifunctional ceramifiable fire-retardant silicone foam (MCSF) was fabricated by Ti3C2Tx nanosheet (MXene), multiwalled carbon nanotube (MWCNT), γ-aminopropyltriethoxysilane (APTES), Karstedt catalyst (Pt) and vinyl dimethylsiloxane via water–oil interface induced self-assembly and dehydrogenation foaming at room temperature. MCSF possessed low density and good mechanical properties. Its improved thermoelectric performance and sensitive fire-warning capability of MCSF were attributed to the skeleton supporting effect and unique electron transport effect between MWCNT and MXene. When being burned, MCSF was able to trigger the fire-warning system within 2.4 s and repeatedly alarm the fire reignition. Furthermore, owing to the synergism between APTES and Pt, MCSF exhibited good ceramization performance. When encountered high temperature, the MCSF surface rapidly ceramized, generating a ceramic-like barrier layer to block the further flame ablation, and it quickly self-extinguished after removing from flame. Besides, MCSF showed impressive thermal insulation and durable piezoresistive sensing. This work provides a new strategy for the preparation and application of multifunctional fireproof polymer foams.

Formulating stable surrogate wood pyrolysis oil-in-oil (O/O) emulsions: The role of asphaltenes evidenced by interfacial dilational rheology

This work presents a novel methodology to obtain stable bio-oil-in-oil emulsions using crude oil endogenous asphaltenes as emulsifiers. This approach provides new insights into the valorization of wood pyrolysis bio-oils through co-processing with crude oils or by direct incorporation in fuels for marine transportation, contributing to a significant reduction of the carbon footprint of these products. Similar to water-crude oil systems, asphaltenes can form a rigid film at the bio-oil / petroleum-derived oil interface, thus limiting droplets coalescence and increasing the emulsion lifetime without requiring additional emulsifier. The evolution of the interfacial layers with the asphaltene content and the nature of the petroleum-derived oil phase were investigated by interfacial rheology. The results show the consolidation of the interfacial layer and the formation of a solid-like film, referred to as “skin” with appropriate asphaltene content and polarity of the oil phase. Changes in the dilational elasticity depend on the asphaltenes aggregation behaviour according to the Yen-Mullins model, and the mechanisms that account for these phenomena are discussed.

Molecular insight into the enhanced oil recovery potential of a seawater-based zwitterionic/anionic surfactant compound for heavy oil reservoirs

Zwitterionic/anionic surfactant mixtures can produce many synergistic effects that benefit heavy oil production. In this work, a seawater-based zwitterionic/anionic surfactant compound was prepared using cocoamidopropyl betaine (CAB) and alkyl polyoxyethylene ether sodium sulfate (AES), emphasizing their synergistic effects in enhancing conventional heavy oil recovery. First, the emulsification capability and the oil displacement efficiency of the surfactant compound were tested through laboratory experiments. Then the impacts of salinity, cation types, surfactant formulation and solution pH on surfactant-surfactant or surfactant-heavy oil interactions were systematically explored through molecular dynamics simulations to unveil the underlying mechanisms of enhanced oil recovery. The results showed that, (1) in a seawater-based system, when the AES/CAB concentration ratio was 1:1, a large wormlike micelle was formed due to the cation bridging of Ca2+ and Mg2+ ions, which not only strengthened the attractive interactions between the AES-SO4− and the CAB-N+ functional groups, but also screened the repulsive interactions between the AES-SO4− and the CAB-COO− functional groups. (2) Through mixed adsorption, the arrangement of AES/CAB molecules at the aqueous/heavy oil interface was more compact. (3) By incorporating the AES/CAB mixture into the associative structures of asphaltene and resins, it could effectively weaken the attraction interactions between the asphaltenes and the resins. Through these synergies, an additional oil recovery of 24.93 % was yielded by combining AES/CAB flooding and subsequent seawater flooding, compared to 19.38 % in the pure AES case. This study provides important insights into the microscopic mechanisms of zwitterionic/anionic surfactant mixtures, which can facilitate the effective development of heavy oil reservoirs and guide the complex formulation of cost-effective surfactant compounds.

Exploring polyaniline nanofiber synthesis at vegetable oil-water interfaces for high-performance hybrid electrochemical capacitors

Polyaniline (PANI) nanofibers are synthesized at five different vegetable oil-water interfaces by a modified interfacial polymerization method. A series of syntheses is performed to study the effect of vegetable oil- water interfaces on the sizes, morphologies and corresponding electrochemical performances of resultant PANI nanofiber samples. Five PANI nanofiber samples are synthesized and the corresponding electrochemical performances as electrochemical capacitor (EC) electrodes are evaluated. It is observed that the PANI nanofiber sample prepared at water-sunflower oil interface, PANI5 possesses the lowest diameter and highest specific capacitance among all the prepared samples. Herein, we have fabricated an all-solid-state asymmetric electrochemical capacitor (AEC) of PANI5 and bio-derived chemically activated carbon (AC). The electrochemical measurements show that PANI5 and AC exhibits specific capacitance of 395 F g−1 and 240 F g−1 respectively at current density 1 A g−1. The fabricated PANI5//AC AEC exhibits areal capacitance of 70 mF cm−2 at current density of 1 mA cm−2. The energy density (Ed) and power density (Pd) of constructed AEC are found to be 19 µW h cm−2 and 696 µW cm−2, respectively. It gives the cyclic stability of 62 % retention of initial areal capacitance after completing 5000 galvanostatic charge-discharge cycles.

Contact Characteristics and Characterization Methods of CO2 and Crude Oil in Visual Porous Medium

In this article, the vertical static variation characteristics of CO2 and crude oil in porous medium under different experimental pressures are studied by using the CO2 miscible visual displacement device jointly developed. The process of change at the CO2 and crude oil interface is characterized by relative height and dissolution expansion rate. Experimental results demonstrate that with the increase of pressure, CO2 gradually reaches a supercritical state with strong extraction and mass transfer capacity, and CO2‐crude oil exhibits different contact forms under different pressures. Under the same pressure, there are also significant differences in contact forms between visual tube and porous medium. The existence of porous medium weakens the mass transfer and diffusion abilities between CO2 and crude oil and reduces the extraction of light components by CO2. In porous medium, the relative height of crude oil is a power function of time, which is 1/5 ≈ 3/10 of that in visual tube. And the dissolution expansion rate of CO2 and crude oil exhibits a negative logarithmic correlation with time, which is 1/4 ≈ 2/5 of that in visual tube. The impact of porous media on relative height and dissolution expansion rate of crude oil becomes more pronounced as the pressure decreases.

Investigating aggregation of heavy oil droplets: Effect of asphaltene anionic carboxylic

Understanding the impact of asphaltene molecules on heavy oil droplet aggregation is vital for oil field development. Here, the impact of terminal carboxyl groups in asphaltene molecules on heavy oil droplet aggregation was investigated. Results suggest that the anionic asphaltenes were more readily adsorbed onto the water–oil interface than normal asphaltenes. Stacking structures between asphaltene and resin involve predominant face-to-face and edge-to-face aggregation. The anionic asphaltene system boosts grid strength (Asp-Asp interaction) and interaction with water (Asp-water interaction) among oil droplet molecules. We hope these insights that can offer strategies for improving the efficiency and sustainability of heavy oil extraction.

Soft sensor development for mixed oil interface tracking in multi-product pipelines based on knowledge-informed semi-supervised Variational Bayesian Gaussian mixture regression

Sequential transportation of petroleum products in multi-product pipelines often lead to occurrence of mixed oil. The prediction of the arrival time of the mixed oil interface constitutes crucial data for the scheduling of treatment actions. However, existing soft sensors, like Gaussian mixture regression (GMR), may face challenges due to limited size of labeled data and numerical issues, leading to performance degradation or even training failure. To tackle these issues, we propose a Knowledge-informed Semi-supervised Variational Bayesian Gaussian mixture model (KI-SSVBGMR). It employs a semi-supervised fully Bayesian structure designed to address the constraints arising from the potential matrix singularity issues and shortage of labeled samples. Subsequently, we determine the crucial regression variable and establish its prior distribution based on industrial knowledge to improve model generalization. Finally, a learning procedure grounded in the Variational Inference algorithm is developed to train the KI-SSVBGMR. Through case studies, including numerical examples and real industrial datasets, our method demonstrates the effectiveness and reliability of the proposed soft sensor development method. This research can aid operators in improving mixed oil section management and provides valuable insights for integrating machine learning with industrial knowledge.

Advanced machine learning-based modeling of interfacial tension in the crude oil-brine-diethyl ether system: Insights into the effects of temperature and salinity

Solvent injection, a well-established method for enhanced oil recovery (EOR), has demonstrated significant improvements in oil recovery when compared with conventional water flooding techniques. The interfacial tension (IFT) is pivotal in determining the displacement efficiency and overall performance of innovative techniques like dimethyl ether-enhanced waterflooding (DEW), which has gained substantial attention in recent years. In this study, following laboratory measurements of IFT, six advanced machine learning (ML) techniques were employed: Generalized Linear Model (GLM), Generalized Additive Model (GAM), Random Forest (RF), Support Vector Machine (SVM), Extreme Gradient Boosting (XGBoost), and Boosted Regression Tree (BRT) to model the IFT in both oil-brine and oil-brine-diethyl ether (DEE) systems. The analysis is based on an extensive dataset comprising 7,017 data points for oil-brine and 6,949 data points for oil-brine-DEE systems obtained from experimental studies. The findings indicate that the developed RF model excels in predicting IFT, boasting a remarkable coefficient of determination (R2 = 0.99) along with the lowest root mean squared error (RMSE = 0.2), mean squared error (MSE = 0.04), and mean absolute error (MAE = 0.13). The study underscores the significance of optimizing salinity levels to achieve the most substantial reduction in IFT. This reduction is attributed to the enhanced migration of polar components, such as asphaltene molecules, to the interface of the oil-brine system. Moreover, the research highlights a synergistic decrease in IFT when both DEE and soluble ions are present, resulting in the lowest IFT at around 2 mN/m in 40,000 ppm salinity (S2) at 70 °C (T3). This indicates that the adsorption of DEE at the water–oil interface forms a layer capable of adsorbing ions, thereby enhancing the layer's thickness. As a result, the oil–solvent-ion layer becomes thicker compared to the oil-ion layer, leading to the maximum decrease in IFT. Additionally, with increasing temperature up to 70 °C, the IFT of both systems demonstrated a downward trend, as evidenced by all experiments. The outcomes of this study have the potential to enhance our comprehension of the underlying mechanisms involved in water-soluble solvent EOR techniques.

A mechanistic kinetic model for lipid oxidation in Tween 20-stabilized O/W emulsions

Models predicting lipid oxidation in oil-in-water (O/W) emulsions are a requirement for developing effective antioxidant solutions. Existing models do, however, not include explicit equations that account for composition and structural features of O/W emulsions. To bridge this gap, a mechanistic kinetic model for lipid oxidation in emulsions is presented, describing the emulsion as a one-dimensional three phase (headspace, water, and oil) system. Variation in oil droplet sizes, overall surface area of oil/water interface, oxidation of emulsifiers, and the presence of catalytic transition metals were accounted for. For adequate predictions, the overall surface area of oil/water interface needs to be determined from the droplet size distribution obtained by dynamic and static light scattering (DLS, SLS). The kinetic model predicted well the formation of oxidation products in both mono- and polydisperse emulsions, with and without presence of catalytic transition metals.

Comparative Study on the Emulsification of Octenyl Succinic Anhydride Modified Sweet Potato Starch: As Macromolecular and Particulate Stabilizers

AbstractSweet potato is one of the essential starch materials for food and feed world widely. However, its application is limited by the low viscosity and poor stability of native starches. Herein, sweet potato starch is modified by octenyl succinic anhydride (OSA) in the aqueous system. The optimization for esterification is studied using response surface methodology. The characteristics of OSA‐modified sweet potato starch are investigated, and its emulsifying properties as macromolecular and particulate stabilizers in the oil‐in‐water systems are compared. The optimal process conditions for OSA modification are: reaction time 4.0 h, temperature 38.8 °C, pH of the reaction system 8.2, starch concentration 32.2%, OSA amount 3.0%. The degree of substitution is 0.0185, and reaction efficiency is 79.7% under the optimum conditions. The new peaks at 1725 and 1573 cm−1 are observed by Fourier transform infrared spectroscopy. Compared with native starch, OSA‐modified sweet potato starch exhibits higher viscosities, improved paste clarity, and decreased retrogradation. The confocal laser scanning microscope results show that the gelatinized starch macromolecule and ungelatinized starch particles can arrange at the water–oil interface. The OSA‐modified sweet potato starch is both an effective macromolecular emulsifier and a particulate stabilizer, effectively stabilizing oil‐in‐water emulsions.

Structural responses of zein-based oil-in-glycerol emulsion gels during freeze-thawing and heating

The current study developed zein based oil-in-glycerol emulsion gels, and tested the roles of different structural components (oil droplets, interface, and network structures) on the properties of the gels when subjected to freeze-thawing and heating. Different structures of the systems were obtained by changing the content of zein, oil, and Span 20. Docking results showed the hydrogen bond, hydrophobic interactions and hydrogen bond, hydrophobic interactions were key interactions between zein-glycerol, zein-oil, zein-Span 20, respectively. Freeze-thawing stability of emulsion gels got declined with the increase in the content of zein, oil and Span 20, and the content of zein played a more significant role. The oil holding capacity and solvent binding capacity of gels were decreased with more cycles of freeze-thawing. Heating process reduced the solvent holding capacity of gels, which was due to the weakened hydrogen bonding of zein-glycerol, and enhanced zein-zein interaction. Gel strength of the systems was significantly enhanced after heating, indicating the denaturation and rearrangement of zein structures in the continuous phase. Overall, the interface and continuous network of zein played crucial roles in tuning the stability of emulsion gels against thermal changes. This study provided novel information regarding the structure-relationship in zein based emulsion gels, and would be helpful to widen the applications of zein in food products.

Effect of hydroxyethyl starch on drug stability and release of semaglutide in PLGA microspheres

The degradation of peptide drugs limits the application of peptide drug microspheres. Structural changes of peptides at the water–oil interface and the destruction of their spatial structure in the complex microenvironment during polymer degradation can affect drug release and in vivo biological activity. This study demonstrates that adding hydroxyethyl starch (HES) to the internal aqueous phase (W1) significantly enhances the stability of semaglutide and optimizes its release behavior in PLGA microspheres. The results showed that this improvement was due to a spontaneous exothermic reaction (ΔH = −132.20 kJ mol−1) facilitated by hydrogen bonds. Incorporating HES into the internal aqueous phase using the water-in-oil-in-water (W1/O/W2) emulsion method yielded PLGA microspheres with a high encapsulation rate of 94.38 %. Moreover, microspheres with HES demonstrated well-controlled drug release over 44 days, unlike the slower and incomplete release in microspheres without HES. The optimized h-MG2 formulation achieved a more complete drug release (83.23 %) and prevented 30.65 % of drug loss compared to the HES-free microspheres within the same period. Additionally, the optimized semaglutide microspheres provided nearly three weeks of glycemic control with adequate safety. In conclusion, adding HES to the internal aqueous phase improved the in-situ drug stability and release behavior of semaglutide-loaded PLGA microspheres, effectively increasing the peptide drug payload in PLGA microspheres.

Simultaneous adjustment on the CO2/oil and CO2/water interface tensions using hydrophilic, lipophilic and CO2-philic surfactants during CO2 flooding to enhance shale oil recovery after hydraulic fracturing

It is an urgent demand to further enhance shale oil recovery after large-scale hydraulic fracturing with a low oil recovery. CO2 flooding technology has been demonstrated to effectively develop shale oil, however, the residual water after hydraulic fracturing can influence the efficiency of CO2 flooding because of the high CO2-water interfacial tension. Here, the hydrophilic, lipophilic and CO2-philic surfactants were investigated to simultaneously adjust the CO2/oil and CO2/water interface tension to accelerate the oil and water flows to enhance shale oil recovery. The results show that the low-carbon alcohol polyoxyethylene polyoxypropylene ether has the hydrophilic, lipophilic and CO2-philic properties. The alkyl chain length and PO groups have great influence on the interfacial tension of CO2-oil, while the presence of EO groups can significantly reduce the interfacial tension of CO2-water. The surfactant of C4EO3PO6 can not only demonstrate the best performance in reducing the interfacial tensions of shale oil-CO2 and water-CO2, but also decrease the minimum miscibility pressure (MMP) of the shale oil-CO2 system to 18.89 MPa from 24.10 MPa. The interfacial tension between water and the CO2 + 1.0 wt% C4EO3PO6 system can be decreased to 6.62 mN/m at 28 MPa and the reduction rate is 56.10 %. The enhancement of surfactants on the extraction effect of CO2 and the mutual diffusion process between CO2 and shale oil or water interface is the major mechanism to decrease the interfacial tensions. Therefore, the addition of surfactant in CO2 can simultaneously decrease the interfacial tensions of CO2-oil and CO2-water and has a potential to enhance shale oil recovery by reducing the capillary resistance of residual water after hydraulic fracturing and increasing the miscibility between CO2 and oil.

Comparative Study of the Performances of Octenyl Succinic Anhydride‐Modified Agriophyllum squarrosum and Quinoa Starches to Stabilize Pickering Emulsions

AbstractVery small granule starch is a good source for effective Pickering emulsion stabilizers. In this study, native Agriophyllum squarrosum (A. squarrosum) starch (N‐AS) and native quinoa starch (N‐QS) are modified by octenyl succinic anhydride (OSA), and the physicochemical as well as the emulsifying characteristics of two modified starches are evaluated. Fourier transform infrared spectroscopy (FTIR) shows that the esterification reactions between OSA and the two starches are successful, and the substitution effect of OSA‐modified A. squarrosum starch (OSA‐AS) is better than that of OSA‐modified quinoa starch (OSA‐QS). X‐ray diffraction (XRD) analysis shows that OSA modification does not alter the crystal type of the starch particles. OSA modification increases the particle size and hydrophobicity of both starches, and the particles of OSA‐AS are smaller than that of OSA‐QS, which corresponded to the fact that N‐AS possesses a smaller particle size compared to native N‐QS. OSA‐modified starches are arranged at the interface of oil–water to stabilize the emulsion. The OSA‐AS displays better performance of stabilizing emulsion than OSA‐QS. The Pickering emulsions formed by all OSA‐modified starch samples are mainly elastic gel‐like emulsions. In summary, OSA‐AS is more suitable for Pickering emulsion stabilizer than OSA‐QS.