Oil-water Surface Research Articles

Investigating the Feasibility of EOR While Preloading Parent Wells to Mitigate Fracture Hits: An Experimental and Modeling Study

Summary During a fracturing operation in an infill (child) well, pressure and fluid communication between this well and a nearby parent well, known as fracture hits (FHs), can impair the production performance of both wells. A cost-effective strategy to mitigate the FH is to preload the parent well with water during the fracturing of the child well. It has been hypothesized that the production performance of the parent well can be enhanced by the preloading process if proper additives are used in the injected water. We develop a laboratory protocol to physically simulate primary production and surfactant preloading stages using Montney core and fluid samples under reservoir conditions. We investigate the role of wettability alteration, interfacial tension (IFT) reduction, and surfactant’s chemical stability on the performance of enhanced oil recovery (EOR) during the preloading process. An analytical model is developed to predict the volume of leaked-off surfactant and recovered oil using measured pressure-decline data from the preloading stage. This study only focuses on the interactions of preloading fluid with the parent well’s matrix and does not consider the child-parent well interference. Our results demonstrate that 31.8% of the oil is recovered during primary production from large inorganic pores under solution-gas drive mechanism. Under countercurrent imbibition, a nonionic surfactant leaks off into the smaller organic and inorganic pores and recovers an additional 11.8% oil from a depleted core during preloading. The analytical model estimates oil recovery factors close to the experimental data determined by material balance. Core visualizations demonstrate a population of small oil droplets on the rock surface under reservoir conditions. While IFT is reduced to nearly the same extent by either surfactant, only the wettability-altering surfactant yields incremental oil recovery. Zeta-potential measurements indicate that while neither surfactant alters the rock-water surface charge, the wettability alteration is achieved by modifying the oil-water surface charge even at concentrations above the critical micelle concentration (CMC). Based on the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, the repulsive electrostatic double-layer (EDL) forces are intensified with an increase in surfactant concentration, resulting in enhanced stability of the water film on the rock surface and increased hydrophilicity. Under elevated temperatures, we observe two phenomena, which can adversely affect the performance of a nonionic surfactant: (a) agglomeration of surfactant particles due to reduced solubility in water, reducing pore accessibility, and (b) chemical decomposition of the surfactant, affecting its ability for IFT reduction and wettability alteration.

Stability enhancement of pickering emulsions based on κ-carrageenan microgel: Synergistic effect of l-lysine and potassium ions at low ionic strength

The study utilized the synergistic effect of l-lysine and K+ to improve the stability of Pickering emulsions based on κ-carrageenan microgels. The gel strength of κ-carrageenan gels, the zeta potential and particle size revealed that the microgel particles prepared with l-lysine and K+ had the potential to be Pickering particles. l-lysine formed electrostatic interactions and hydrogen bonds with κ-carrageenan. Structural modifications of microgel particles by l-lysine (0.05%–0.10%) and low K+ strength (≤40 mmol/L) promoted the formation of a dense interface layer at the oil-water droplet surface to prevent the accumulation of oil droplets and further significantly enhance the appearance and centrifugal stability of Pickering emulsions. The microstructure and rheological analysis showed that K+ at low ionic strength, in cooperation with l-lysine, formed a more tightly structured layer between the microgel particles wrapped on the surface of oil droplets, thereby enhancing the stability of emulsions. In conclusion, these Pickering emulsions with prolonged stability are expected to be suitable healthy animal fat substitutes for use in food applications.

Effects of wax on the formation of methane hydrate in oil-dominate systems: Experiments and molecular dynamics simulations

Hydrate formation and wax deposition in underwater multiphase pipelines have become two vital problems affecting the flow assurance safety. Experiments and molecular dynamics (MD) simulations were performed to investigate the effect of wax crystals on hydrate nucleation and growth. Our experimental results showed that wax crystals had an inhibitory effect on hydrate growth, but played a dual role in methane hydrate nucleation (promotion and inhibition). The addition of wax could decrease mass transfer coefficient of methane by increasing viscosity of oil phase, which lower methane supply from the oil bulk phase to the oil–water interface. The simulation results revealed that the wax crystals at the interface influenced the mass transfer of methane molecules instead of providing heterogeneous nucleation sites. Small wax crystal adjacent to the oil–water interface accelerated methane supersaturation dissolution and restricted gas diffusion in the aqueous phase because of adsorption to methane, which promoted hydrate nucleation and shifted the nucleation position toward the oil–water interface. While the large wax crystal could effectively block the methane mass transfer from oil phase to aqueous phase by covering the oil–water surface, which reduced the concentration of methane in the aqueous phase and prolonged the induction time of hydrate formation. These results of this work would provide a better understanding of the interaction mechanism between hydrate and wax.

Co-stabilization mechanisms of solid particles and soluble compounds in hybrid Pickering emulsions stabilized by unrefined apple pomace powder

Vegetal by-product powders, such as apple pomace powder, represent an efficient green alternative to conventional emulsifiers to stabilize oil-in-water Pickering emulsions. The natural material being used without purification, its multiple components shall impact differently the emulsion stability and interact with each other. These effects might be either synergic, competitive, or both depending on their ratio. Herein, the co-stabilizing effects of the apple pomace compounds on Pickering emulsions were explored from microscopic to macroscopic scales. The apple pomace powder was first fragmented into several fractions which were characterized (particle sizes, shape and wettability, oil-water surface activity). Emulsions were then prepared by varying the stabilizing material composition using the different fractions obtained from the apple powder. Emulsions properties (droplet size, rheological properties) and stability were monitored over a month. The key role of solid particles in the surface activity of the apple pomace powder was shown by interfacial tension measurements. All particle-stabilized emulsions were stable against coalescence during storage despite high droplet diameters (up to 80 μm) and low surface coverage. Soluble matter and particles show a synergic behavior to stabilize oil-in-water emulsions. The soluble matter drives droplet size whereas insoluble cellulosic particles are responsible for emulsion stability by both Pickering adsorption to the oil droplet and oil droplet trapping in a three-dimensional network. This study provides new insights into the understanding of natural powders stabilizing mechanisms that may lead to a better prediction of the potential of vegetal by-products as stabilizing agents from their chemical composition.

The emulsifying ability of oleosomes and their interfacial molecules

Oleosomes are natural oil droplets, present in all organisms and abundant in oilseeds. After their aqueous extraction from oilseeds, they can be directly utilized as oil droplets in food, cosmetics and all types of oil-in-water emulsion systems. However, to expand the potential uses of oleosomes as green ingredients and to valorize oilseeds as efficient as possible, we explored their emulsifying ability. Oleosomes were extracted from rapeseeds, and 10.0 wt% oil-in-water emulsions were created after homogenization with 0.5–6.0 wt% oleosomes, and the droplet size of the emulsions and their structure was measured by laser diffraction and confocal laser scanning microscopy (CLSM), respectively. The emulsion with an oleosome concentration lower than 1.0 wt% gave unstable emulsions with visible free oil. At oleosome concentrations at 1.5 wt% or higher, we obtained stable emulsions with droplet sizes between 2.0 and 12.0 µm. To investigate the role of the oleosome interfacial molecules in stabilizing emulsions we also studied their emulsifying and interfacial properties (using drop tensiometry) after isolating them from the oleosome structure. Both oleosomes and their isolated interfacial molecules exhibited a similar behavior on the oil-water interfaces, forming predominantly elastic interfacial films, and also showed a similar emulsifying ability. Our results show that oleosomes are not stabilizing the oil-in-water emulsions as intact particles, but they provide their interfacial molecules, which are enough to stabilize an oil-water surface up to about 2 times bigger than the initial oleosome surface. The understanding of the behavior of oleosomes as emulsifiers, opens many possibilities to use oleosomes as alternative to synthetic emulsifiers in food and pharma applications.

Microscale Reservoir Wettability Evaluation Based on Oil–Rock Nanomechanics

Low oil production and rapid production decline epitomize the challenges of unconventional reservoir development. Rocks in the formation with micro-/nanoscale pore-throat units possess an immense surface area. Consequently, the wettability of rocks plays a crucial role in the relative permeability of oil/water, the injection pressure, the distribution and morphology of residual oil, and hence the ultimate oil recovery. Contact angle, as a frequently used method to evaluate wettability, is susceptible to oil-water saturation, imbibition, and surface roughness of rock slices. In addition, the measurement scale (droplet of several millimeters) does not match the flow scale (pore units in micro- or nanoscale). Therefore, this paper established a new wettability evaluation method based on oil–rock interaction. Molecular dynamics simulation results demonstrated that the interaction energy between the oil molecule and walls with different wettabilities shows a distinct discrepancy. Accordingly, nanomechanics by AFM was utilized to measure the oil molecule–pore wall interaction force. It was found that the interaction force increases with the augmented hydrophobicity of the pore wall due to hydrophobic force. In addition, the reservoir rock wettability index was defined using the oil–rock interaction force in the nanoscale. The wettability index has an excellent linear correlation with the intrinsic contact angle. The wettability evaluation method based on the oil–rock interaction force is more direct, facile, and rapid and overcomes the limitation of the traditional contact angle method.

Numerical Investigation on EOR in Porous Media by Cyclic Water Injection with Vibration Frequency

Water injection with an oscillatory pressure boundary is a promising technology, which can achieve a more economical and environment-friendly EOR (enhanced oil recovery). However, due to the unclear critical injection frequency, its oil production performance has been unstable and is far from reaching the optimal level. Here, a numerical model is established for oil recovery by the water injection with the oscillatory boundary condition to find out the critical frequency for the optimal EOR. The correlations between the water injection frequency and the EOR level at diverse oil–water surface tensions and oil viscosities are integrated into the model. Our numerical model reveals that an optimal EOR of roughly 10% is achieved at the critical water injection frequency compared with water injection without an oscillatory boundary. The EOR mechanism is revealed showing that upon water injection with the optimum frequency, the formation of the preferential pathways is inhibited and the pressure transmits to the wall sides to displace the oil. Moreover, it is indicated that the required critical frequency increases with higher surface tension and larger oil viscosity. In addition, the difference between the residual oil saturation at the optimal frequency increases with the increase in surface tension compared with water injection without an oscillatory boundary. Last but not least, it is elucidated that at a constant injection frequency, a higher EOR is achieved when the water–oil surface tension is lower but the oil viscosity is larger. Our work promises economic, eco-friendly and controllable enhanced oil recovery.

Hydrophobic polyacrylonitrile/pitch electrospun nanofibers for oil spill cleanup: Fabrication, optimization, and kinetic investigations

In the present work, the polyacrylonitrile/pitch composite electrospun nanofibers were successfully fabricated to cope with oil spills from the sea surface. The response surface methodology (RSM) was applied to optimize the pitch content, applied voltage, and flow rate to achieve the optimal conditional for absorbing oil. The optimal parameters of pitch content, applied voltage, and flow rate were determined at 18.3 %, 15.3 kV, and 0.95 mL/h, respectively. The hydrophobicity of composite nanofibers was investigated by water contact angle (WCA) analysis. The results showed that the WCA of the composite nanofibers was 139.4°, proving that the fabricated nanofibers were hydrophobic. Compared to pure polyacrylonitrile nanofibers, the polyacrylonitrile/pitch composite nanofibers exhibit better oil-water selectivity and surface roughness under optimized conditions. The composite nanofibers showed good oil absorption for different kinds of oils (up to 42.47 g/g within 5 min), which was 3–5 times that of commercial polypropylene absorbents. The oil absorption of the composite nanofibers was still >70 % after 10 absorption-desorption cycles. Moreover, the absorption kinetics study showed that the pseudo-second-order kinetic model was more suitable for the oil absorption process of the polyacrylonitrile/pitch composite nanofibers. This study explored the potential application value of low-value-added petroleum pitch. The fabricated composite nanofibers have promising applications in the oil/water separation and the absorption of oil spills.

Cellulose nanofibril-stabilized Pickering emulsion as a high-performance interfacial biocatalysis system for the synthesis of phosphatidylserine

An efficient and attractive platform for synthesizing phosphatidylserine is indispensable for driving large-scale industrial applications. Given the interfacial effect of phospholipase D (PLD), an adequate oil-water interface surface is essential for the catalytic efficiency of PLD. Herein, a simple ball-milling method with ionic liquid was successfully applied to produce cellulose nanofibrils and immobilized PLD with the cellulose-binding domain through a one-step procedure. Each droplet in the Pickering reaction system was regarded as a microreactor to provide sufficient oil-water interface to the active sites of PLD. The constructed Pickering emulsion system exhibited outstanding catalytic activity, achieving 95.4 % conversion after 2 h with the minimal amount of catalyst (0.8 wt% of CNF-CBD1 addition amount), which was 6-fold higher than the previously reported immobilized MCC-CBD1 and 21-fold higher than free PLD-CBD1. These results demonstrated a sustainable and high-performance biocatalysis method, paving the way for the efficient synthesis of novel phospholipids.

STUDIES OF ANTICORROSIVE PROPERTIES MOTOR OILS AND WAYS TO IMPROVE

The purpose of this work is to study how to improve the anticorrosive properties of lubricants. With an increase in temperature, the combined action of oxygen, air and water present in the lubricating oil causes rusting of the crankshaft, the walls of the sleeves, the cylinders of the internal combustion engine. We have studied anticorrosive additives as an additive to improve the anticorrosive properties of oils. dialkylphenyldithiophosphoric acid additive was used as such additives. The anticorrosive activity of these substances is associated with their ability to orient themselves on the oil–water surface so that hydrophilic groups bind firmly to water, and the hydrocarbon radical remains in the oil.

Preclinical evaluations of Norcantharidin liposome and emulsion hybrid delivery system with improved encapsulation efficiency and enhanced antitumor activity

ABSTRACT Background Norcantharidin (NCTD) has a certain degree of hydrophilicity and poor lipophilicity, and has some side-effects, including short t1/2, vascular irritation, cardiotoxicity, and nephrotoxicity, which bring difficulties for formulation research. In this study, we aim to develop a novel nanocarrier to improve encapsulation efficiency, increase sterilization stability, and enhance antitumor activity. Methods Phospholipid complexes methods were used for increasing the lipophilicity of norcantharidin (NCTD), then NCTD phospholipid complexes were not only loaded in the oil phase and oil-water interface surface, but also encapsulated in phospholipid bilayers to obtain NCTD liposome-emulsion hybrid (NLEH) delivery system. The in vitro cytotoxicity and apoptosis, in vivo tissue distribution, tumor penetration, heterotopic, and orthotopic antitumor studies were conducted to evaluate therapeutic effect. Results NLEH exhibited an improved encapsulation efficiency (89.3%) and a better sterilization stability, compared to NCTD liposomes and NCTD emulsions. NLEH can achieve a better antitumor activity by promoting absorption (1.93-fold), prolonging blood circulation (2.08-fold), enhancing tumor-targeting accumulation (1.19 times), improving tumor penetration, and increasing antitumor immunity. Conclusions The liposome-emulsion hybrid (LEH) delivery system was potential carrier for NCTD delivery, and LEH could open opportunities for delivery of poorly soluble anticancer drugs, especially drugs that are more hydrophilicity than lipophilicity.

Robust and durable superhydrophobic and oil-absorbent silica particles with ultrahigh separation efficiency and recyclability

With the continuous occurrence of oil-spill accidents, superhydrophobic materials demonstrate tremendous potential in oil-water separation. In this research work, SiO2 nanospheres with surface mercapto groups were prepared by the condensation reaction of 3-mercaptopropyltriethoxysilane (KH590) and hydroxyl groups on the surface of silica (SiO2) particles. Subsequently, HTPB-coated SiO2 superhydrophobic particles were obtained through the thiol-ene click chemistry reaction between the SiO2 nanospheres and the hydroxyl terminated polybutadiene (HTPB). Depending on the polar attraction between the terminal hydroxyl groups of HTPB and the hydroxyl groups on the surface of SiO2, SiO2 nanospheres could be firmly coated with HTPB. Fortunately, stable and durable superhydrophobic lipophilic SiO2 particles (Si-HTs) was obtained. Because of the existence of micro-nano structures, the resultant Si-HTs could easily float on the oil-water surface, and effectively absorb oil solvents more than 4 times its own weight with an ultrahigh separation efficiency above 99%. Even under strong acid and strong alkali conditions or in the seawater environments, the Si-HTs were afforded with effective oil-absorption capability and high recyclability over 20 times. Consequently, the Si-HTs prepared show great potential as a superhydrophobic nanoparticle for low-cost, high-efficiency and environmentally friendly oil-water separation.

Effect of alkyl chain configuration of tertiary amines on uranium extraction and phase stability – Part I: Evaluation of phase stability, extraction, and aggregation properties

Amine-based extraction processes are broadly exploited for the selective extraction of uranium from sulfuric leaching liquors. The molecular forces (that is, the enthalpy associated with the multi-scale structuration of tertiary amines) are balanced by entropic effects that have not yet been identified. This first part in a series of reports describes the effects of the alkyl chain configuration on the phase stability and aggregation properties of tertiary amines. It is demonstrated that tertiary amines with longer or slightly branched alkyl chains provide better phase stability and enable constant extraction of uranium. In comparison, more branching of the alkyl chains hinders the formation of a highly curved interfacial layer, thus preventing efficient extraction. Combined small-angle scattering determination of the nanostructures in the organic phase and oil–water surface tension measurements revealed that the alkyl chains effects on the efficiency of the extraction process and phase stability are associated with reverse aggregates with smaller polar core volumes and less co-extracted water, suggesting that packing of the alkyl chains has a direct impact on the extraction efficiency of the solvent extraction system.

Twist and Stretch: Assignment and Surface Charge Sensitivity of a Water Combination Band and Its Implications for Vibrational Sum Frequency Spectra Interpretations.

The vibrational spectrum of water at hydrophobic/hydrophilic interfaces is crucial to understanding complex surface chemistry phenomena. Vibrational sum frequency (VSF) spectroscopy is a valuable nonlinear spectroscopic technique for exploring the details of vibrational spectra of molecules at surfaces. However, spectral assignments and analysis of VSF spectra are often more nuanced than in linear spectroscopy. This study is aimed at understanding the source of the broad VSF signal in the oil-water surface water spectrum at energies slightly higher than traditionally examined, beyond the unbound free OH oscillator of surface water molecules. Analyzing isotopic dilutions of the aqueous solvent with VSF spectroscopy, we demonstrate that this signal is due to a combination band of water stretch and libration motions. The spectral characteristics of this band are found to be highly sensitive to the sign and magnitude of the surface charge induced by adsorption of both anionic and cationic surfactants. The results have implications for VSF measurements of the C-H stretching vibrations of various adsorbates when studied with D2O as the aqueous solvent. Because the vibrational signal from the water combination band is dependent on surface charge, it is imperative to include the presence of the combination band when fitting surface spectra.

(Invited) Mulling over Nanoemulsions: Interfacial Molecular Structure, Stabilization and Assembly

Nanoemlusions are finding numerous applications in the fields of pharmaceuticals, food production, materials synthesis and cosmetics. With the search for broader and improved usage of these unique droplets comes the need to better understand the molecular interactions at the surface that lead to their stabilization. This presentation will focus on our most recent efforts to understand the molecular assembly and structuring present at an oil-water droplet surface that contributes to the stabilization of these nano-sized oil droplets in water, and similarly sized water droplets in oil. The studies are a combination of spectroscopic and thermodynamic measurements coupled with theoretical simulations.

Ways to improve the anticorrosive properties of motor oils used in vehicles

In recent years, increased requirements for protective properties have been imposed on petroleum oils for various purposes. One of the functions of the oil is to protect the surface of parts from corrosion. Corrosion becomes especially intense when the engine is operated in hot, humid climates. In this case, oil plays a double role: on the one hand, it protects the surfaces of parts from the aggressive influence of the external environment; on the other hand, the oil itself is corrosive due to the presence of corrosive substances in it. Corrosion is especially intensified after the engine is stopped. When it cools, moisture condenses on the parts, the lubricating oil, flowing down from the lubricated surface, cannot protect the metal from corrosion. The reason for the corrosive properties of oils is that they contain organic and inorganic acid peroxides and other oxidation products and sulfur compounds, alkalis, and water. The purpose of this work is to study and improve the anti-corrosion properties of lubricants. With an increase in temperature, the combined action of oxygen in the air and water present in the lubricating oil causes rusting of the crankshaft, liner walls, cylinders of the internal combustion engine. We have studied anticorrosive additives as an additive to improve the anti-corrosion properties of oils. Dialkylphenyl orthophosphoric acid additive was used as such additives. The anticorrosive activity of these substances is related to their ability to orient themselves on the oil-water surface so that hydrophilic groups are firmly bound to water while the hydrocarbon radical remains in the oil.

Investigation of Rotating Disk Skimmer Hydrodynamic Performance during Oil Spills Recovery (Dept.M)

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Surface matrix functionalization of ceramic-based membrane for oil-water separation: A mini-review

Advanced filtration requires a cost-effective, highly efficient and environmentally friendly membrane fabrication to achieve excellent and extreme oleophobic and hydrophilic states with an appropriate surface functionalization approach. For an efficient oil-water separation, surface material and structure have been categorized as superoleophobic (high oil repellency) and superhydrophilic (strong affinity to water). This can be attributed to their selective mechanisms. In addition, it is very important to consider these key factors as they will imperatively provide a unique capability to exhibit surface roughness, stimulate low and high surface energy, and improve surface chemistry, which makes membranes function efficiently for the oil and water separation system. In this review article, the application of ceramic membrane for oily water treatment and the principle of superhydrophilic and superoleophobic ceramic membrane for oil-water separation are elaborated and, in addition, the current progress for the use of inorganic material to functionalize ceramic membrane surface based on physical and chemical methods is appraised. Finally, the challenges and outlook on the membrane for oily-water treatment are briefly examined.

Study of surface complexation modeling on a novel hybrid enhanced oil recovery (EOR) method; smart-water assisted foam-flooding

This contribution focuses on surface complexes in the calcite-brine-surfactant system. This is relevant for the recovery of oil when using a new hybrid enhanced oil recovery (EOR) method, which combines smart-water (i.e., ionically modified brine) and foam-flooding (SWAF) of light oil with dissolved carbon dioxide (CO2) at high pressure in carbonate (i.e., calcite) reservoirs. Using this new hybrid EOR-method (i.e., the SWAF-process) is not only economically attractive (i.e., it reduces opex costs) but also enhances the effectiveness of the production process, and thus reduces the environmental impact. Ionically modified brine (i.e., low-salinity) has a dual improvement effect. It not only leads to more stable foam lamellae, but also helps to change the carbonate rock wettability, leading for some conditions to more favorable relative permeability behavior. The mechanism for the modified permeability behavior in the presence of ionically modified brine is only partly understood. Therefore, we study this process initially in a zero dimensional (thermodynamics) setting, which can be used for the one dimensional (1D) displacement process with an oleic phase that contains carbon dioxide (CO2) and an aqueous phase that contains both carbon dioxide (CO2) and all the ionic substances. Using DLVO theory and surface complexation modeling to better understand the mechanism(s) of ionically modified brine as wettability modifier and foam stabilizer. We perform simulations using both (NaCl) and (MgCl2) to show the effect of a divalent ion at the high-salinity (8500 mmol/kg-w) and low-salinity (0.4 mmol/kg-w) for both ambient-conditions at (25°C) and at the reservoir-conditions (80°C). We confine our analysis to a description that uses the Dzombak-Morel model of surface complexes, which is based on the Debye-Hückel theory (i.e., valid up to ionic strength of 0.3 (mol/kilogram of water)). We also investigate the effect of carbon dioxide (CO2) on the stability of low-salinity foam-laminae. We model the foam-laminae, which contain as surface complex a (cationic) surfactant in an aqueous phase. We use the PHREEQC-software to calculate the surface charge and the surface potential. The presence of a carbon dioxide (CO2) phase leads to dissolution of four valent C(IV) compounds in the aqueous film. PHREEQC also calculates the equilibrium concentrations and surface potential and allows the study of the effect of salinity and the carbon dioxide (CO2) gas pressure. For the soap-film (foam-film) in a carbon dioxide (CO2) atmosphere we do use Pitzer activity coefficients (i.e., valid up to 6 (mol/kilogram of water)). As our aim is to show the methodology and the versatility of this approach, we leave more realistic choices of these parameters for future work.sFor the conditions considered we can qualitatively state that, in the presence of (NaCl i.e., at pH > 10) and (MgCl2 i.e., pH > 10.3), the low-salinity case shows a more stable water-film behavior at (25°C) and at (80°C) than the high-salinity case for both (25°C) and (80°C). Moreover, high carbon dioxide (CO2) pressures have a destabilizing effect on the film, as they reduce the surface potential. A reduced surface potential leads to a decreasing electrostatic double layer repulsion and thus destabilizes the foam-film, whereas low-salinity leads to less screening of the surface potential and thus improves the stability of the foam-film. The low-salinity flow is characterized by a high residual oil saturation and low end-point permeability for the two phase oil-water flow. This leads to a more favorable mobility ratio and thus a more favorable displacement process. For the calcite surface an enhanced stability helps to stabilize the water film on the calcite surface if the oil-water surface charge has the same sign as the surface charge on the calcite surface. Our calculations show the pH range where the sign of these charges is the same or opposite at low-salinity and high-salinity conditions. Admittedly these calculations only show trends, but can be used to delineate optimal conditions for the application of “Smart Water Assisted Foam (SWAF) Flooding”. It is expected that the SWAF-process under the optimum conditions will make the proposed new hybrid Enhanced Oil Recovery (EOR) process environmentally and economically attractive.

Effect of Oil–water Surface Area on the Aroma Release Behavior of Mono-dispersed Oil-in-water Emulsions

Effect of Oil–water Surface Area on the Aroma Release Behavior of Mono-dispersed Oil-in-water Emulsions