Oil-water System Research Articles

Deep learning-assisted dual-modal tomography for phase flow rate estimation in two-phase oil-water flow systems

Accurately estimating phase flow rates in multiphase systems is crucial for many industries, where precise measurements are essential for operational efficiency and safety. Addressing this issue, this paper introduces an approach that employs deep learning-assisted dual-modal electromagnetic flow tomography (EMFT) and electrical tomography (ET) to predict both oil and water flow rates in two-phase oil-water flows. To facilitate the generation of the data, we first simulate diverse flow conditions using COMSOL Multiphysics software and the convection–diffusion equation, aiming to create a realistic representation of two-phase oil-water flows. The dual-modal system measurement data, generated from these simulations and simulated by using a dense finite element mesh, provide reliable inputs for the deep learning model. Moreover, this study also integrates experimental data into both the training and testing phases, improving the ability of the proposed approach to estimate flow rates accurately in practical investigations. The results from laboratory experiments demonstrate the potential of the deep learning-assisted dual-modal ET and EMFT approach in effectively resolving the challenges of estimating flow rates in two-phase oil-water flow systems. By combining the deep learning capabilities with dual-modal tomography, this study offers valuable insights for future applications and represents a significant step forward in the field of multiphase flow rate estimation.

Alkane molecularly imprinted nanofiber membranes used to enhance the diesel degradation process

AbstractCombining molecular imprinting technology with electrostatic spinning technology, a molecularly imprinted nanofiber membrane material with memory and recognition of specific imprinted molecules is thus produced. It has the advantages of high efficiency, reusability, easy amplification, and simple operation. In this study, alkane molecularly imprinted nanofibrous membranes are prepared as a carrier for immobilize Bacillus cereus LY‐1 for the degradation of diesel in oil–water system. The adsorption capacity of the molecularly imprinted material for diesel oil with n‐decyl alcohol as the template molecule reach 120.25 mg g−1, the adsorption capacity of alkane molecularly imprint nanofiber membrane prepared using polyvinyl alcohol (PVA) as the membrane substrate material is 41.37 mg g−1. After 4 days, the immobilized LY‐1 cells eliminate roughly 80.7% of the diesel at a starting concentration of 3 g L−1. The results show that imprinted structures in MINM enhance degradation by loaded microorganisms.

Effects of Stepdown Pressure and Wettability on Bubble Nucleation in Gas-Supersaturated Oil-Water Systems

Summary This study investigates the influences of wettability and stepdown pressure on pressure-driven bubble nucleation within a gas-supersaturated oil-water system. Two gases—carbon dioxide (CO2), which is highly soluble in water, and methane (CH4), which is sparingly soluble in water—were used individually for the bubble nucleation experiments. Equal heights of oil (n-decane) and water, in a wettability-controlled glass vial placed in a saturation cell, were saturated with either of the gases at 6000-mbar pressure, followed by applying a stepdown pressure of either 6000 mbar, 500 mbar, or 100 mbar to start the bubble nucleation process. The average bubble nucleation pressures for CO2 and CH4 gases on a hydrophobic vial surface with 500-mbar stepdown pressure were 4333 ± 289 mbar and 3833 ± 289 mbar, respectively. It is important to note that the bubble nucleation took place exclusively on the portion of the solid surface submerged in water. However, bubble nucleation did not take place with 100-mbar stepdown pressure for either gas in the hydrophobic vial despite the pressure being brought down to atmospheric pressure. As expected, bubble nucleation did not take place in the hydrophilic vial for the gases despite the pressure being brought down to atmospheric pressure from the saturation pressure, regardless of the stepdown pressure. In addition, bubble nucleation did not take place in CO2-supersaturated water in the oil-wetted hydrophilic and hydrophobic vials, even at maximum supersaturation.

Determination of Biogenic Amine Level Variations upon Storage, in Chicken Breast Coated with Edible Protective Film.

A new chitosan-based protective film containing rosemarinic acid (0.282% w/w) has been elaborated. The film was formed from a water-oil emulsion system and applied to poultry meat samples using a dip-coating technique. Various physicochemical parameters of the coatings, such as thickness, Young's modulus, elongation at break, water vapor transmission rates, and antioxidant activity, were tested with free-standing film samples peeled from a Petri dish. Compared to neat chitosan films obtained similarly, new films cast from the emulsion showed significantly better elasticity (Young's modulus was diminished from 1458 MPa to about 29 MPa). Additionally, barrier properties for moisture transition decreased from 7.3 to 5.8 g mm m-2 day-1 kPa-1. The coated poultry samples were subsequently evaluated in juxtaposition with uncoated ones in a storage test. Levels of selected biogenic amines (histamine, tyramine, tryptamine, phenylethylamine, putrescine, cadaverine, spermine, and spermidine), total bacterial count, and lipid oxidation levels in the meat samples were analyzed during storage at 4 °C (up to 96 h). The results obtained for the biogenic amines, total bacterial content, calculated biogenic amine index, and the ratio of spermidine to spermine in meat samples suggest the advantage of the proposed coatings with rosmarinic acid in protecting poultry meat against environmental factors and rapid spoilage.

Study of hydrate generation risk in gas-saturated oil-water emulsion system based on artificial intelligence

The formation and plugging of hydrates in oil and gas pipelines will bring serious challenges to the safe operation of oil and gas pipelines, but at present, domestic and foreign researchers have not formed a unified understanding of the formation mechanism of hydrates in oil and gas pipelines as well as the plugging mechanism, and its study is still a hot issue in the current domestic and foreign research. For the problem of hydrate plugging in oil and gas pipelines, one of the key parameters is the volume fraction of hydrate in the pipeline, the size of which is directly consistent with the trend of hydrate plugging in the pipeline, and therefore it can be used as a characterisation parameter for the trend of hydrate plugging in oil and gas pipelines. However, the calculation of the volume fraction of hydrate in pipeline is still difficult, especially the quantification of the volume fraction of hydrate in pipeline under the flow regime is affected by multiple parameters, which has become a difficult research point in the industry. To address the above problems, this thesis first carries out flow system experiments to explore the formation, blockage and hydrate volume fraction of hydrates in oil and gas pipelines under different operating parameters, and then establishes a hydrate volume fraction prediction model by using artificial intelligence deep learning methods, trains the model parameters on the above experimental data, and uses the prediction model to predict the other experimental data, and obtains better Effect. It guides the future application of artificial intelligence technology in the prevention and control of natural gas hydrate in oil and gas pipelines.

Robust and flexible polyester fiber membrane with under-liquid dual superlyophobicity for efficient on-demand oil-water separation

Functional materials with under-liquid dual superlyophobicity have generated a great deal of concern from researchers due to their switchable separation ability oil-water mixtures and emulsions. Conceptually, under-liquid dual superlyophobicity is a Cassie state achievable under-liquid through the synergy of an under-liquid double lyophobic surface and the construction of a highly rough surface. However, obtaining an under-liquid dual superlyophobic surface remains difficult due to its thermodynamic contradiction and complex surface composition. Herein, we successfully prepared a functional coating by modifying the mixture of cellulose nanocrystals (CNCs) and nano-TiO2 with perfluorooctanoic acid (PFOA) via a simple method, then obtained a polyester fiber membrane with under-liquid dual superlyophobicity by roll coating method. The surface wettability of the polyester (PET) membrane was altered, transforming it from the original under-water oleophobic/under-oil superhydrophilic state to the under-water superoleophobic/under-oil superhydrophobic state after coated. The resulting membrane was applied to separate oil and water on-demand. The coated PET membrane exhibited high separation efficiency (>99 %) and high separation flux, effectively separating immiscible oil-water systems as well as oil-in-water and water-in-oil emulsions. The coated PET membrane also demonstrated the ability to perform alternate separation of oil-water mixtures through wetting, washing, and rewetting cycles, with repeated processes up to 10 times without significant reduction in separation efficiency. Furthermore, compared with the previous works, our approach offers a simpler and more convenient method for constructing under-liquid dual superlyophobic surface, making it more suitable for continuous corporate production. This study may provide inspiration for the production and application in large-scale of under-liquid dual superlyophobic membranes.

Microwave-induced thermal response and protein variation of oil-water biphasic systems in foods: A Case study of anhydrous butter and skim milk

Oil and water are crucial constituents of liquid foods; however, the effect of their varying dielectric properties and distribution forms on microwave heating remains unclear. The study investigated microwave absorption and subsequent quality consequences in oil-water biphasic systems (two-layer liquid and emulsion). Food-derived skim milk and anhydrous butter were selected for research. The developed numerical model demonstrated that the distribution configuration and oil content affected the microwave heating pattern. Vertical temperature gradients were observed in both systems. The temperature in the two-layer liquid was higher than that in the emulsion with 20% oil content for the strong-intensity electric field in the oil and the high dielectric permittivity of water. Moreover, the upper thermal zone during microwave heating triggered milk protein unfolding, thereby exposing more free sulfhydryl groups. Protein composition analysis showed partial degradation of milk proteins. This study provides a basic understanding of microwave heating of liquid food biphasic systems.

Synthesis of Functionalized Flexible and Rigid Polyurethane for Oil Spill Treatment

Abstract. To improve the oleophilic and hydrophobic properties of two different types of polyurethane sponge (flexible, FPU, and rigid, RPU) for oil spill cleanup, acrylamido phenyl chalcone palamitamid, a recently synthesized monomer with long chains of linear alkyl groups, was in situ crosslinked with divinylbenzene. Grafted PU cubes were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The water sorption of ungrafted FPU and RPU decreased from 18.05 and 15.66 to 7.31 and 7.06 for grafted FPU and RPU, respectively. The effect of oil type on the sorption capacity testing was explored and compared using crude oil, diesel fuel, and water-oil systems. It was found that the crude oil and diesel fuel sorption of grafted FPU and RPU cubes was increased compared with ungrafted FPU and RPU cubes, and the maximum values for adsorption were recorded using crude oil. These results can be explained by increasing the adherent forces between the adsorbent and the oil surface with increasing oil viscosity, and consequently, the oil adsorption increases. The high oil absorption capacity is mainly attributed to the high porosity of the sponges. The modified FPU and RPU cubes can be effectively used in oil and water spill cleanup.

Experimental study on the effect of quaternary ammonium salt + monoethylene glycol compound to methane hydrate agglomeration in oil-water system

Natural gas hydrate has been a critical risk to the safety of offshore oil and gas well test and subsea transportation. Herein, the effect of three quaternary ammonium salt (QAS) surfactants with monoethylene glycol (MEG) to methane hydrate agglomeration in water-oil system was experimentally studied by a rocking cell. Based on the hydrate volume fraction and the slider trajectory, a classification method of the gas hydrate anti-agglomerants was established. All the QASs in this work show the capability of reducing hydrate agglomeration, among which N1,N3-didodecyl-N1,N1,N3,N3-tetramethylpropane-1,3-diaminium chloride (AA-2) has the best anti-agglomerating performance, and the slider moved at a large trajectory of 61–174 mm. The three QASs were compounded with 5, 10, and 15 wt% (based on water) MEG, respectively. Experimental results showed that AA-2 compounded with MEG (10 wt%) can effectively prevent hydrate agglomeration. The slider moved in the cell at the full trajectory range, showing the compound of grade A performance. The compound of QAS and MEG shows a synergistic effect. The addition of QAS can significantly reduce the required MEG dosage for the hydrate blockage prevention than the MEG only situation. Considering the economic factors of the filed hydrate management, the combination application of QAS + MEG may provide a promising option.

Biphasic control strategy of polymers and nanoparticles for viscous oil removal and molecular release: Synthesis, mechanism and applications

Responsive Pickering emulsions are an excellent platform to control the interfacial properties of oil–water systems. However, the removal of viscous crude oil from oily waste by external stimuli is still a challenge. Here, a dual-stimuli supramolecular assembly of the polymer and silica particles (PS) was designed to achieve desirable control of oil–water interfaces for viscous oil removal and controlled molecular release. The β-cyclodextrin-based polymer was fabricated through the atom transfer radical polymerization (ATRP) method for the host molecules responsive to UV light and amine-modified silica particles for the guest molecules responsive to pH. Utilizing their responsive properties, the PS system was demonstrated in this study to significantly enhance the oil washing efficiency (from 18.3% to 74.2%). Moreover, as the acidic condition was replaced by CO2 injection, it was further enhanced from 74.2% to 88.5%, which is beneficial to greener remediation and production. The responsive PS assembly was also applied for dye release with a slower or faster release of methyl red by tuning the stimuli (pH & UV light). The molecular mechanism was revealed via the molecular dynamics (MD) simulation, which articulates the interaction and motion of the PS system under various stimulations. More importantly, this novel assembly of the cyclodextrin-based polymer and amine-modified silica particles affords a simple and efficient route to enhance the removal of viscous oil waste and precisely control the molecular release. The findings of the molecular self-assembly in this work offer unique opportunities to integrate functional polymers and particles into the liquid–liquid interface, opening an avenue for applications in Pickering emulsions.

Biphasic water-oil systems for functional augmentation of probiotic Lactobacillus acidophilus nanoencapsulated in luteolin-Fe3+ shells.

Single-cell nanoencapsulation (SCNE) has great potential in the enhancement of therapeutic effects of probiotic microbes. However, the material scope has been limited to water-soluble compounds to avoid non-biocompatible organic solvents that are harmful to living cells. In this work, the SCNE of probiotic Lactobacillus acidophilus with water-insoluble luteolin and Fe3+ ions is achieved by the vortex-assisted, biphasic water-oil system. The process creates L. acidophilus nanoencapsulated in the luteolin-Fe3+ shells that empower the cells with extrinsic properties, such as resistance to lysozyme attack, anti-ROS ability, and α-amylase-inhibition activity, as well as sustaining viability under acidic conditions. The proposed protocol, embracing water-insoluble flavonoids as shell components in SCNE, will be an advanced add-on to the chemical toolbox for the manipulation of living cells at the single-cell level.

Analysis of the causes of flooding of long-term deposits under conditions of high geological heterogeneity

In this work, the object of research was the long-term deposits of liquid hydrocarbons located within the boundaries of fields with high geological heterogeneity, the proportion of which is actively increasing every year due to the selection of a significant part of the “light” oil reserves. Based on the generalization of the results of direct and indirect research on the topic of the work, the key causes of well flooding were identified and their primary sources were identified, which made it possible to successfully describe the mechanisms of formation of the transition zone of the oil-water system, depending on the stage of development. The conclusion is made about the importance of applying relevant and reliable scientific and methodological approaches in interpreting the results of geophysical research to solve various problems of oil field development.

Simulation study on the coupled heat and mass transfer of CO2 in a heavy oil-water liquid system based on an improved lattice Boltzmann (LB) method

This study investigates the heat and mass transfer when low-temperature CO2 diffuses in a heavy oil–water liquid system based on an improved Lattice Boltzmann (LB) method. First, we determine the CO2 diffusion coefficients in heavy oil and water and the heat transfer coefficients of heavy oil and water using the pressure drop (DP) method and the laser flash (LF) method, respectively. Then, a numerical model that couples the heat and mass transfer in the system is established based on the improved LB method. The effect of low-temperature CO2 on the temperature field of the system and the effect of changes in the temperature field on CO2 diffusion are investigated. Finally, we develop a micro-model reproducing the heat and mass transfer of CO2 in water and heavy oil-saturated porous media to validate the accuracy of the numerical model. The results demonstrate that the CO2 diffusion coefficients in heavy oil and water linearly increase with the temperature increases. The heat transfer coefficients of heavy oil and water are insensitive to the changes in temperature. The heat transfer process has a great impact on the mass transfer of CO2 in the liquid system. The CO2 diffusion velocity slows down as the system temperature decreases because of the heat transfer (from 400 K to 300 K), leading to a reduction percentage of 300 % in the CO2 front movement velocity. Compared to the scenarios neglecting heat transfer, CO2 diffusion distance and amount decrease by 38 % and 50 %, respectively because of the changes in the temperature field of the system.

Green Polymer Poly‐l‐proline Efficiently Inhibits Formation of Gas Hydrates in Oil–Water System

AbstractGreen polymer poly‐l‐proline, as a new type of biodegradable polymer material, has a wide application prospect in the field of environmental protection. Recent studies have shown that poly‐l‐proline can also act as a green inhibitor that is highly effective in inhibiting the production of gas hydrates in oil–water systems. As a natural polymer material, poly‐l‐proline has good biocompatibility and biodegradability and will not cause pollution to the environment. It is found that adding an appropriate amount of poly‐l‐proline to the oil–water system can significantly inhibit the formation of gas hydrates. This is because poly‐l‐proline can reduce the concentration of dissolved gases in water by adsorbing and dispersing ions and molecules in water, thereby reducing the chance of gas forming hydrates with water. In addition, poly‐l‐proline can also prevent gas molecules from entering water molecules to form hydrates by forming hydrogen bonds with water molecules. This study provides a green, environmentally friendly and efficient solution for controlling the formation of gas hydrates in oil–water mixtures. In the future, the application prospects of poly‐l‐proline in oil–water separation, marine engineering, natural gas exploitation, and other fields will be broader.

3D model for inertial cavitation bubble dynamics in binary immiscible fluids

The physics of cavitation bubbles in water has been extensively studied for over a century. However, our understanding of bubble dynamics in binary immiscible fluids, such as a water-oil system, is limited. These systems have recently gained a lot of interest due to their relevance in modern medical treatment, emulsification, and the food industry. In this study, we establish an accurate and inexpensive three-dimensional boundary integral (BI) model for inertial cavitation bubble dynamics in binary immiscible fluid systems. Our novel scheme for solving velocities on the flow boundaries, expressed in a matrix form, can be easily extended to complex situations where multiple bubbles are generated in different phases. Additionally, we employ a density potential method and a weighted moving least-squares method to maintain a high level of mesh regularity. Our results demonstrate that the proposed 3D model is comparable in accuracy to a 3D axisymmetric model by comparing it against analytical solutions and the results obtained from an axisymmetric model. Furthermore, we compare our numerical simulations against a purposely conducted experiment for the bubble-droplet interaction, and excellent agreement is achieved. For the first time, we present simulation results of two-bubble interactions with an initially flat fluid-fluid interface and inside a droplet surrounded by a second fluid. We also reveal the dependences of the two-bubble morphologies, flow patterns, and jet velocities on the density ratio between the two phases. Finally, we find a significant difference in the mechanism of fluid mixing by multiple bubbles compared to that of a single bubble case.

Effect of Silica Nanoparticles to Span 80 and Cocamidopropyl Dimethylamine in Methane Hydrate Formation and Agglomeration in Water–Oil System

Effect of Silica Nanoparticles to Span 80 and Cocamidopropyl Dimethylamine in Methane Hydrate Formation and Agglomeration in Water–Oil System

Bio-inspired and green fabrication of superhydrophobic materials with good robustness, stability and flame retardancy for oil-water separation based on waste cotton

Recently, more and more attention has been paid to bionic superhydrophobic materials for treating the intricate oil-water mixture system for the sake of resource recovery and environmental protection. With the in-depth development of research, scientists have been committed to pursuing the superhydrophobic materials via the economical, clean, and environmentally friendly methods. The current bio-inspired innovation of this paper concentrates on constructing superhydrophobic porous materials based on green, low-cost, and renewable waste cotton via in situ hydrothermal growth and solution immersion strategy. As anticipated, the water contact angle (WCA) of the prepared superhydrophobic cotton materials reaches 158°, exhibiting good self-cleaning ability and oil/water separation efficiency (99% ± 1%). Compared with pure cotton, superhydrophobic cotton materials also possesses elevated flame retardancy. In addition, after 300 cm abrasive paper friction tests, 10 times oil-water separation tests, 7 days of acid and alkali immersion tests (pH=1, 13), salt water immersion tests, and UV irradiation tests, as-prepared cotton materials can still maintain excellent superhydrophobic properties. On the basis of this work, an effective, facile and environmentally-benign avenue for fabricating the super-hydrophobic materials has been exploited that displays the promising applications in fields of waste cotton recycling, oil spill treatment and oil/water separation.

Synergistic performance of a Gemini nano ionic liquid and sodium dodecyl sulfate surfactants at the crude oil–water interface

Gemini surface active ionic liquids (GSAILs) are known as effective and environmentally friendly materials. Conventional anionic surfactants like sodium dodecyl sulfate (SDS), on the other hand, can establish desired properties in solutions. This study reports investigation on the influence of the mixtures of an imidazolium cationic GSAIL, [C4im-C6-C4im][Br]2, and the SDS anionic surfactant on the interfacial tension (IFT), emulsification, and wettability alteration of the crude oil–water system. Results demonstrate amazing synergistic effects, resulting in 97.1 % more IFT reductions compared to what could be achieved with the linear contribution of surfactants. Under the GSAIL mole fraction of 0.4 and the mixture concentration of 0.25 molˑdm−3 in aqueous phase, a low IFT of 0.18 mNˑm−1 was attained. This is attributed to the attractive interaction between the involved surfactants. Synergisms of 52.0 and 59.8 % were also achieved in emulsification and wettability alteration with the mixture of surfactants under the optimum GSAIL mole fraction of 0.4. The obtained data for the individual and the mixture of surfactants were analyzed based on, respectively, Frumkin adsorption isotherm and the “non-ideal interactions in binary mixtures” theory. Corresponding consistent parameters were determined and discussed.

Effect of Titanium Dioxide Nanoparticles on Surfactants and Their Impact on the Interfacial Properties of the Oil-Water-Rock System.

The application of nanoparticles (NPs) in the oil and gas industry has received wide attention in recent years because it is increasingly being considered a promising approach to recovering trapped oil in conventional hydrocarbon reservoirs. Numerous studies have demonstrated that combining nanoparticles with a surfactant can enhance surfactant performance by changing the interfacial properties of the solution when it comes in contact with crude oil and rock surfaces. However, more information and additional experimental data are required concerning the application of titanium dioxide nanoparticles in alkyl ethoxy carboxylic surfactants. In this study, we measure the changes in interfacial tension and wettability due to the addition of titanium dioxide nanoparticles (0, 100, 250, and 500 ppm) in alkyl ethoxy carboxylic surfactant using a spinning drop tensiometer and contact angle measurements. The interfacial tension of the crude oil-water (surfactant) system decreases by approximately two orders of magnitude with an increasing titanium dioxide concentration, exhibiting a minimum value of 5.85 × 10-5 mN/m. Similarly, the contact angle decreases on the surface of the Berea sandstone by combining the surfactant with titanium dioxide, reaching a minimum contact angle of 8.8°. These results demonstrate the potential of this new approach to maximize the recovery of trapped oil and significantly improve oil production.

Division Method of Dynamic Flow Units in Fluvial Reservoir at Ultra-high Water Cut Period

The heterogeneity of fluvial sedimentary reservoir is serious. The division of flow units in the early stage of development can provide a good guidance in the well pattern distribution and reservoir production. Due to the huge changes in the oil-water system in the long-term development reservoir, the flow units divided at the initial stage are difficult to guide the production when entering the ultra-high water cut period. Therefore, it is necessary to redefine the division indicators and methods of flow units, so as to provide support for the formulation of efficient regulation and control technology. Starting from the definition of flow unit, this paper establishes the percolation coefficient as the characteristic index of percolation capacity. Combined with the percolation characteristics of fluvial reservoir, the dynamic flow unit division method with percolation coefficient and water cut as division parameters is established. Through the division results of typical models of fluvial reservoir, it can be seen that the four types of flow units divided by the dynamic flow unit method in this paper can play a great guiding role in the later formulation of regulation and control measures. The verification of reservoir examples shows that the division results of dynamic flow units of fluvial facies can well reflect the remaining oil enrichment areas in the reservoir and classify the remaining oil enrichment areas. At the same time, the dynamic flow unit changes continuously with the development process, which can more clearly show the producing degree of each remaining oil enrichment area after the regulation and control measures. This provides a key support for formulating targeted and efficient reservoir development technique.