表面活性剂/盐/油酸甲酯模拟油体系协同效应机理研究

从油相性质和水相性质对具有一定亲水-亲油能力的表面活性剂在油水界面上吸附的影响出发,研究模拟油中的有机添加剂(有机酸、长链醇)和不同结构的原油酸性活性组分与外加表面活性剂之间以及不同亲水、亲油能力的二元混合表面活性剂之间在降低界面张力方面的协同效应。油相中的油酸甲酯通过改变外加表面活性剂在油、水相之间的分配而影响界面浓度,从而影响界面张力,随着油相中油酸甲酯浓度的增加,油相中有机活性物质与不同结构的外加表面活性剂之间的协同效应有正有负,协同效应是正还是负与具体的水相性质密切相关。提出了判别表面活性剂与模拟油中有机物降低界面张力方面协同效应正负的经验方法,用该经验方法得出的结果与实验结果完全一致。图6参7     

表面活性剂/盐/油酸甲酯模拟油体系协同效应机理研究

从油相性质和水相性质对具有一定亲水-亲油能力的表面活性剂在油水界面上吸附的影响出发,研究模拟油中的有机添加剂(有机酸、长链醇)和不同结构的原油酸性活性组分与外加表面活性剂之间以及不同亲水、亲油能力的二元混合表面活性剂之间在降低界面张力方面的协同效应.油相中的油酸甲酯通过改变外加表面活性剂在油、水相之间的分配而影响界面浓度,从而影响界面张力,随着油相中油酸甲酯浓度的增加,油相中有机活性物质与不同结构的外加表面活性剂之间的协同效应有正有负,协同效应是正还是负与具体的水相性质密切相关.提出了判别表面活性剂与模拟油中有机物降低界面张力方面协同效应正负的经验方法,用该经验方法得出的结果与实验结果完全一致.图6参7     

Alkaline Surfactant Polymer Formulation for Carbonate Reservoirs

Abstract

This paper presents a systematic study to investigate the applicability of alkaline-surfactant-polymer (ASP) process as an enhanced oil recovery method to Saudi Arabian carbonate reservoirs. Several alkalis were first screened to test their compatibility with the injected sea water that has large quantities of divalent ions. Then surfactant-polymer, alkali-surfactant, and alkali-surfactant-polymer interactions at the reservoir temperature (90^○C) were investigated. Static adsorption of surfactant on reservoir carbonate rocks were also investigated at the same temperature. Interfacial tension (IFT) measurements were made between the slugs formulated and crude oil from the same reservoir. Two surfactants were tested, Triton X-102 and Ethoxylated sulfonate (Dodiflood B1083), and the polymer tested was FLOCON 4800C.

The results of the compatibility tests showed that the ASP slug has to be prepared using softened seawater and be protected by a pre- and after-flush softening seawater slugs. B1083 surfactant was found to be a promising candidate surfactant for the adverse conditions of the Saudi Arabian carbonate reservoir. A combination of NaHCO₃ and Na₂CO₃ was found to significantly reduce the adsorption level of B1083 surfactant on carbonate rock at low surfactant concentrations ( < 1% by wt.). This is very desirable for formulation of a cost-effective ASP slug.     

Adsorption kinetics of natural surfactants on carbonate minerals in enhanced oil recovery processes

One of the most promising methods for improving oil recovery from carbonate reservoirs is surfactant flooding in which the trapped oil can be mobilized by alteration in the wettability of rock surfaces and also reduction in the interfacial tension between oil and water. Adsorption of surfactants on carbonate minerals plays a key role in designing this process and may make it less effective for enhancing oil recovery. Natural surfactants have been proposed by many researchers since they have lower cost and also less detrimental environmental effects compared to the industrial surfactants. Well-established predictive models for predicting the adsorption of natural surfactants have some issues which need to be addressed. Therefore, developing an accurate, rapid and simple model is crucial. In this study, a least square support vector machine (LSSVM) optimized with coupled simulated annealing (CSA) algorithm is developed for accurate prediction of natural surfactants kinetic adsorption on carbonate minerals. Obtained results by this model were in a very good agreement with experimental results. Additionally, the results showed that the proposed model has the highest accuracy and performance in comparison to the previous kinetic models. Afterward, the effect of natural surfactants adsorption on the amount of oil recovery and also the quality of the produced oil was investigated via core flooding tests for showing the importance of determining the adsorption of surfactants before any surfactant flooding. Results demonstrated that lower surfactants adsorption yields higher oil recovery factor and oil with higher viscosity.     

Synthesis hydrophilic hybrid nanoparticles and its application in wettability alteration of oil-wet carbonate rock reservoir

In this study, synthesized SiO₂/ZnO hybrid nanoparticles were used to change the wettability of carbonate rock from highly oil-wet to strongly water-wet state. The SiO₂/ZnO nanoparticles were synthesized by modified sol-gel method. In this method, TEOS was used to increase the functional groups on the surface of the ZnO nanoparticles to produce highly hydrophilic nanoparticles. The contact angle measurements were conducted on the rock surface before and after nano-treatment. The contact angle of oil droplet with the rock changed from 0° to 150°, 161°, 164° and 170° after impregnation the rock with 0.01, 0.033, 0.07 and 0.33 wt.% nanofluids.     

Novel application of PEG/SDS interaction as a wettability modifier of hydrophobic carbonate surfaces

Wettability alteration of carbonate reservoirs from oil-wet to water-wet is an important method to increase the efficiency of oil recovery. Interaction between surfactants and polymers can enhance the effectiveness of surfactants in EOR applications. In this study, the interaction of polyethylene glycol (PEG) with an ionic surfactant, sodium dodecyl sulphate (SDS), is evaluated on an oil-wet carbonate rock surface by using contact angle measurements. The results reveal that wettability alteration of carbonate rocks is achieved through PEG/SDS interaction on the rock surface above a critical aggregation concentration (CAC). The behaviour of PEG/SDS aqueous solutions is evaluated using surface and interfacial tension measurements. Furthermore, the effect of PEG and SDS concentrations and impact of electrolyte addition on PEG/SDS interaction are investigated. It is shown that electrolyte (NaCl) can effectively decrease the CAC values and accordingly initiate the wettability alteration of rocks. Moreover, in a constant SDS concentration, the addition of NaCl leads to a reduction in the contact angle, which can also be obtained by increasing the aging time, temperature and pre-adsorption of PEG on the rock surface.     

双子表面活性剂临界胶束浓度规律研究进展

临界胶束浓度是表面活性剂自聚形成胶束的重要参数。双子表面活性剂是具有双亲水基团、双疏水链的表面活性剂,比常规表面活性剂具有更低的临界胶束浓度和更高的表面活性。了解影响双子表面活性剂临界胶束浓度的内在、外在因素,有助于理解分子间的相互作用,分析碳链和联接基团等分子结构对其性能的影响,探究双子表面活性剂的自组织行为,从而更好地发挥双子表面活性剂的高表面/界面活性,开发新型高效表面活性剂。文中介绍了双子表面活性剂临界胶束浓度常用的测定方法,总结了双子表面活性剂疏水基团、联接基团、亲水基团、温度、无机盐等对双子表面活性剂临界胶束浓度的影响,并对影响结果进行了分析。     

Wetting alteration of mica surfaces with polyethoxylated amine surfactants

Characterization of reservoir wettability is an important part of assessment of potential oil recovery. Oil-based drilling fluids include surfactants, which can alter the wettability of mineral surfaces. Cores exposed to these fluids may not reflect the true wettability of the reservoir materials.The focus of this study was to observe wettability changes induced by adsorption and removal of surfactants of known structure on mica surfaces using tools that are applicable to studies of wetting alteration by crude oil components. The surfactants used were polyethoxylated coconut and tallow amines with chain lengths of 12 and 18 carbons and head groups consisting of two to five ethoxy groups. Mica was exposed to decane solutions of the surfactants. The treated mica was characterized macroscopically using contact angle measurements and microscopically using atomic force microscopy (AFM).Upon exposure to the surfactant solutions, the mica became oil-wet ( 170° for both advancing and receding conditions). AFM examination of similarly treated surfaces imaged in air revealed surfactant layers that were easily disrupted or surfaces that showed no surfactant at all. Contact angles were in the intermediate to water-wet range if the mica samples were removed from the surfactant solution, rinsed with non-aqueous solvents, and submerged in decane for measurements of water/decane contact angles. These results suggest only weak surfactant adsorption occurred from non-aqueous solutions. Differences among the structures tested were greater for increased levels of ethoxylation; differences due to hydrocarbon chain length were negligible. Stronger adsorption, higher contact angles, and more stable surfactant layers could be demonstrated when mica was exposed to aqueous solutions after surfactant sorption, depending on the pH of the aqueous phase. Low pH conditions that promote protonation of the surfactants' amine head group produced the greatest wetting alteration. Above a pH of 8 or 9, no surfactant remained adsorbed on mica surfaces.     

Effect of surfactants and their blend with silica nanoparticles on wax deposition in a Malaysian crude oil

The present study investigated the wax deposition tendencies of a light Malaysian crude oil(42.4° API), and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the wax inhibition research revolved around polymeric wax inhibitors, which cause environmental issues, we highlighted the potential of surfactants and their blend with SiO_2 nanoparticles as wax deposition inhibitors. Different surfactants including oil-based, silane-based, Gemini and bio-surfactants were considered as primary surfactants. The primary surfactants and their respective blends at a concentration of 400 ppm were screened as wax inhibitor candidates using cold finger apparatus. The screening results showed a significant influence on the paraffin inhibition efficiency on wax deposition by using 400 ppm of silane-based surfactant, which decreased the wax deposition up to 53.9% as compared to that of the untreated crude oil. The inhibition efficiency among the silane-based surfactant(highest) and bio-surfactant(lowest)revealed an appreciable difference up to 36.5%. Furthermore, the wax from the treated sample was found to deposit in a thin gel-like form, which adhered inadequately to the surface of the cold finger. A further investigation by blending the 400 ppm silane-based surfactant with a 400 ppm SiO_2 nanoparticle suspension in a load ratio of 3:1 found that the wax inhibition decreased up to 81% as compared to the scenario when they were not added. However, we have shown that the synergy between the silane-based surfactant and the nanoparticles is influenced by the concentration and load ratio of surfactant and nanoparticles, residence time, differential temperature and rotation rate.     

Effect of salinity and rock type on sorption behavior of surfactants as applied in cleaning of petroleum contaminants

Surfactants are of potential importance in the development of new techniques for enhanced oil recovery as well as for remediation of petroleum contaminated soils. With surfactant washing, 95% of the petroleum contaminants can be removed. As sorption dictates the reactions between a liquid and a solid, it is a decisive factor for the success of a remediation technique and for understanding the mechanisms which dictate transport and fate characteristics of contaminants in soils. The adsorption of surfactants from solution at the solid/liquid interface is a complex and imperfectly understood phenomenon. To investigate the nature of adsorption and desorption at the solid/liquid interface, a detailed experimental study was conducted using silica sand packs and clayey sand packs. Also, over twenty numerical simulation runs were conducted to model the phenomenon of surfactant adsorption and desorption. A simulation model based on surface excess concept was developed in this study. Numerical simulation results show excellent agreement with experimental results. This study showed that both salinity and clay can increase the adsorption level of surfactants. The role of surfactant concentration was studied. A higher concentration led to earlier surfactant breakthrough.     

复合驱体系化学剂静态损失评价方法研究

化学剂的损失程度直接影响化学段塞的使用效率。仅考察经油砂吸附后的化学剂损失,不能全面反映驱替过程中的化学剂静态损失程度。为此系统考察了三元复合驱体系经油砂和油相吸附后,表面活性剂质量分数和组成、NaOH质量分数及三元体系与原油间界面张力的变化。三元复合驱组成为:HPAM1.5g/L,表面活性剂上限质量分数0.3%,NaOH上限质量分数1.2%。实验结果表明,经油砂7次吸附后,表面活性剂质量分数从0.28%降至0.02%;NaOH质量分数从1.10%降至0.71%;三元体系经油砂5次吸附后,与原油间的界面张力已无法降至10^-3mN/m数量级。经油砂吸附后的三元体系与油相作用后,表面活性剂质量分数降低,最大降幅达50%,表面活性剂分子量明显升高;而NaOH质量分数降幅较小,最大降幅仅为15.22%;经油砂3次吸附后的三元体系与油相作用后,与原油间的界面张力已无法降至10^-3mN/m数量级。建议将油砂吸附与油相充分作用相结合,综合评价驱替液的化学剂静态损失程度。     

Gemini表面活性剂的研究进展

Gemini表面活性剂是一类新型的表面活性剂，被称为第三代表面活性剂。Gemini表面活性剂含有两个亲水基和两个疏水基。结合国内外的最新研究，对Gemini表面活性剂的结构、合成、性能和应用作了较全面的评述。     

阳离子Gemini对固体表面润湿性的影响

研究了阳离子双子表面活性剂对固体表面润湿性的影响，并从机理上进行了探讨，结果表明，与普通表面活性剂相比，阳离子双子表面活性剂在很低浓度时就能将油湿的固体表面转化为强水湿表面，并且不会改变水湿表面的润湿性；另外，对联接基长度相同但是疏水烷基链长度不同的双子表面活性剂对固体表面的润湿性影响进行了考察，结果发现疏水烷基链短的双子表面活性剂较疏水烷基链长度长的双子表面活性剂更能显著影响固体表面的润湿性。     

The Effect of Ionic Surfactants on the Electrokinetic Behavior of Asphaltene from a Maya Mexican Oil

Abstract

In this work we show the behavior of the zeta potential of asphaltene when different concentrations of two cationic surfactants (cetylpyridinium chloride and dodecylamine hydrochloride) and one anionic surfactant (sodium dodecyl sulfate) interact with asphaltene particles at different pHs in the aqueous phase. By changing the concentration of cetylpyridinium chloride, dodecylamine hydrochloride, and sodium dodecyl sulfate from 0.01 to 1 mM, we were able to reverse and control the sign of the zeta potential of asphaltene, demonstrating the presence of both electrostatic and hydrophobic interactions at the asphaltene surface.     

Evaluation of the ability of the hydrophobic nanoparticles of SiO2 in the EOR process through carbonate rock samples

More than 50% of oil remains in reservoirs after primary and secondary recovery processes. Consequently, methods of enhanced oil recovery (EOR) should be applied for more recovery from these reservoirs. In this study the ability of hydrophobic nanoparticles of sio₂ in EOR process through carbonate rock samples is studied. By employing hydrophobic nanosilica, we can lower interfacial tension between oil and nanofluid and then reduce the mobility ratio between oil and nanofluid in carbonate reservoirs; however, nanosilica can increase the viscosity of water exponentially. To evaluate this goal, core displacement experiment for carbonate core is conducted. These experiments are performed on the carbonate samples saturated with oil and brine that had got injected with nanosilica with six different concentrations. Investigating the outcomes shows that by rising nanoparticle concentration, the IFT between water and oil phases decreases and yields in decrease the mobility ratio between oil and nanofluid. For this, we measure the recovery level in different states of using 0.05, 0.1, 0.1, 0.15, 0.3, 0.6, 1.0, and 0 concentration of the nanoparticle. The outcomes achieved from our experiments reveals that employing hydrophobic nanosilica could increases the oil recovery factor.     

Synthesis and evaluation of some derivatives of polysiloxanes

Silicone surfactants have been widely used in our daily life and many industrial fields on the basis of their unusual properties. Only in the past decades has the use of silicone as a hydrophobic building block for the preparation of surfactants become common. The recent trend to combine silicone, polyoxyalkylene and carbohydrate moieties in the same molecule has resulted in a plethora of new compounds with new properties.In this article, we report the preparation of a series of “glycopolysiloxanes” surfactants with different molecular weights. They were structurally characterized by IR, ¹H NMR and MS.Specifically, the critical micelle concentration (cmc), effectiveness of surface tension reduction (π_cmc), maximum surface excess (Γ_max), minimum surface area (A_min) and standard free energies of micellization (ΔG°_mic) and adsorption (ΔG°_ads) have been determined from aqueous surface tension measurements using Du-Nouy Tensiometer (KRUSS K6 type 4851) with a platinum ring. All the surfactants have good surface properties and have low cmc.The bacteriostatic power of these polymers was tested and compared under the same conditions in aqueous solution against common strains of Gram positive bacteria and strains of Gram negative bacteria.     

Enhanced Oil Recovery and Adsorption of Ionic Surfactant

In this work, three ionic surfactants (F, G, and H) were evaluated in surfactant adsorption experiment and oil recovery tests. Both sets of tests were carried out in a surfactant flooding apparatus, using 30 psi as pressure gradient. The concentration of the solutions injected in adsorption and recovery tests were 30–80% above the critical micelle concentration, to ensure micelle formation. The results obtained showed that adsorption was higher for G (2.7 g.L^?1) and the better oil recovery was for G (89.0%).     

Study the adsorption properties of magnetite nanoparticles in the presence of different synthesized surfactants for heavy metal ions removal

Co-precipitation method is used to prepare magnetite nanoparticles (Fe₃O₄) which stabilized by two nonionic and one cationic surfactant. ¹H NMR used to confirm the chemical structure of the synthesized surfactants. The prepared magnetite nanoparticles characterized by size distribution (DLS), Fourier transform infrared spectroscopy (FTIR), and magnetic properties (magnetic susceptibility analysis). X-ray diffraction (XRD) illustrated a cubic crystalline structure of the prepared magnetite nanoparticles. Transmission electron microscope (TEM) images showed that the magnetite nanoparticles had uniformly dispersed. The adsorption efficiency of the prepared nanoparticles toward lead, zinc, and cadmium, metal ions was estimated by using atomic absorption spectroscopy (AAS). There are several factors controlling the uptake enhancement studies of the synthesized nanoparticles such as the pH of the metal ion solutions and adsorbent doses.     

Effect of salinity on the IFT between aqueous surfactant solution and crude oil

The effect of salts and different surfactants on the equilibrium as well as dynamic interfacial tension (DIFT) between crude oil and water was investigated. Three different types of surfactants with identical hydrophobic chain length C₁₂: Sodium Lauryl Ether Sulphate (SLES), Dodecyl Trimethyl Ammonium Bromide (DTAB), Polyoxyethylene (23) lauryl ether (C₁₂E₂₃) were used in this study. SLES shows better synergism of salt and surfactant mixture amongst the surfactants studied. The order of synergism of salts with the surfactant observed was MgCl₂>CaCl₂> NaCl. The results obtained from partition coefficient study show that the addition of salts favours the partition of surfactants into the oil phase hence reduce IFT more effectively. DIFT results reveal that, salt accelerates the surfactant migration towards the interface, hence, reducing the t^* value.     

INTERFACIAL PROPERTIES OF THE PRODUCTS OF OZONOLYSIS OF HAMACA CRUDE OIL

A sample of extra-heavy Hamaca crude oil, dissolved in carbon tetrachloride, was oxidated with ozone for a few minutes. The reaction mixture was washed with a concentrated solution of HCl, neutralized with sodium carbonate, and the products were extracted from the aqueous phase. The products were characterized by using gel permeation chromatography (GPC), elemental analysis, ¹H nuclear magnetic resonance (NMR), and Fourier transformed infrared (FTIR) techniques. The results of the analyses show that the products have lower molecular weights, lower aromatic character, and higher oxygen content than the original sample. They also indicated that these products were mainly carboxylic acids, aldehydes, and/or ketones, with a higher affinity for water than for carbon tetrachloride, the organic solvent that was used. Interfacial tension γ measurements (water–toluene) performed with these products showed a linear dependence with concentration, where γ dropped from 32 to about 7.7 dinas/cm at the apparent critical Micelle concentration (cmc) (2 g/L). Larger quantities of a commercial sample of nonylphenol ethoxylated were needed for an equivalent γ drop. In another experiment the above oxidated product was mixed with Furrial asphaltene in toluene, and γ measurements were performed as above and compared with the values obtained for the same experiment using the ethoxylated surfactant. In this case, the γ values for the oxidated product were higher, suggesting a better adsorption on the asphaltene colloids. These preliminary results suggest that these oxidated products could be employed as general surfactants in the oil industry.