CMC系列高分子表面活性剂与原油超低界面张力形成机理的研究

采用动态激光光散射及环境扫描电镜研究了羧甲基纤维素系列高分子表面活性剂与大庆原油形成超低界面张力的机理.结果表明,CMC系列高分子表面活性剂具有与低分子量表面活性剂相比拟的表/界面活性,其水溶液的表面张力可达2835mN/m,界面张力达到10^-110mN/m.碱的加入可显著降低高分子表面活性剂与原油的界面张力,在适当条件下界面张力达到超低值(10^-3mN/m),可望作为三次采油的驱油剂.等效烷烃模型研究表明,用碱与原油酸性组分的作用来解释碱能使界面张力下降至超低值的传统观点是不完善的,加入碱能使高分子表面活性剂胶束解缔,胶束数量增多,胶束粒径减小,单分子自由链增加,有利于高分子表面活性剂向界面迁移和排布,这是高分子表面活性剂和碱复配体系与原油界面张力下降至超低值的主要原因.     

Experimental Study of the Effect of Strong Alkali on Lowering the Interfacial Tension of Oil/Heavy Alkylbenzene Sulfonates System

Experimental studies were conducted to explore the fundamental mechanisms of alkali to lower the interfacial tension of oil/heavy alkylbenzene sulfonates (HABS) system. Sodium hydroxide was used as the strong alkali chemical to investigate the interfacial tension (IFT) of oil/HABS system. The influences of salt and alkali on the interfacial activity were studied by the measurement of interfacial tension and partition coefficient. Moreover, the alkali/surfactant solutions were measured by dynamic laser scattering. The results showed that compared with the salt, the function of alkali to lower the interfacial tension and improve partition coefficient is more significant. The micelles formed by surfactants could be disaggregated because of adding alkali, so the size of micelles decreases and the number of mono‐surfactants increases, then more surfactant molecules move to the interface of oil/surfactant system and the adsorption of surfactants at oil‐water interfaces increases, which can lead to the decrease of IFT.     

Study on synthesis and performance of lignin polyether sulfonate surfactants for enhanced oil recovery

Lignin polyether sulfonate surfactants with lipophilic groups of different polymerization degree were synthesized and the dynamic interfacial tension (IFT) between solutions of these surfactants prepared with brine and two kinds of oil from Daqing and Huabei Oilfields were measured, respectively. The results showed that the surfactants were effective to lower the IFT between brine and the two kinds of oil. The structures of synthesized surfactants were analyzed by Fourier transform infrared spectroscopy. The contents and hydrophilic–lipophilic balance values of lignin polyether sulfonates were studied to evaluate the basic physicochemical properties of synthesized surfactants.     

Effect of Aqueous Phase pH on the Dynamic Interfacial Tension of Acidic Crude Oils and Myristic Acid in Dodecane

The time dependence of the interfacial tension between water–acidic crude oil and water–synthetic oil was investigated for aqueous phase pHs ranging from 2 to 9 using the du Noüy ring method at 20°C. Myristic acid in dodecane was selected as a model (synthetic oil) for acidic crude oil containing indigenous surfactants, and the similarities and differences between the dynamic interfacial tension behaviours of the natural and synthetic crude oil systems were compared. The initial interfacial tension and the relaxation of the interfacial tension are sensitive to the aqueous phase pH for both systems. The adsorption kinetics of the indigenous surfactants and myristic acid could be well fitted with the monoexponential model, and the time constants obtained in this manner indicates that reorganization of the indigenous surfactants and myristic acid at the w/o interface are pH dependent. The experimental results also indicate that indigenous surfactants in acidic crude oil and myristic acid in dodecane have similar film formation behaviours at the w/o interface for the range of pHs investigated.     

Effect of Alkanolamide on Interfacial Tension and Loss of Petroleum Sulfonates for Enhanced Oil Recovery

Experimental studies are conducted in order to elucidate the mechanisms of monoethanolamide responsible for synergism on lowering interfacial tension and decreasing loss due to adsorption on surface of reservoir sand and precipitation with multivalent cations in model oil/water/surfactants/brine systems. The interfacial tensions between solutions containing crude oil and monoethanolamide, petroleum sulfonates, or mixture of monoethanolamide and petroleum sulfonates at different ratios are studied without any alkali added in the solution. The results show significant synergic effect between monoethanolamide and petroleum sulfonates can reduce the interfacial tension to ultralow. Adsorption isotherms of monoethanolamide, petroleum sulfonates and mixture solution are determined to assess the effect of monoethanolamide on reducing the loss of petroleum sulfonates in formation. Static adsorption experiments indicate that the loss of petroleum sulfonates for adsorption and precipitation can be reduced on a great degree when monoethanolamide is mixed with petroleum sulfonates. The core-flooding tests show that the enhanced oil recovery with the formulation of surfactants of 0.3 wt% petroleum sulfonates and 0.2 wt% monoethanolamide can be increased by 26.6% without any alkali added in the flooding solution.     

三元复合驱碱/表面活性剂/聚合物模拟原油乳状液稳定动力学特性

基于两相分离的乳状液稳定模型,研究了三元复合驱模拟原油乳状液稳定动力学特性;通过液膜强度和油水界面张力探讨了碱/表面活性剂/聚合物对模拟原油乳状液稳定动力学特性的影响机理。 结果表明,乳状液稳定模型可以很好的评价乳状液的稳定性,并得到乳状液的稳定动力学特性;碱浓度小于900 mg/L有利于乳状液的稳定,碱浓度大于900 mg/L不利于乳状液的稳定;表面活性剂和聚合物浓度的增加使得形成的模拟原油乳状液更加稳定;模拟原油乳状液的稳定作用主要是通过碱、表面活性剂降低油水界面张力并增加油水界面膜强度,聚合物通过提高界面膜强度实现的,三者存在协同效应。     

Gemini阴离子表面活性剂水溶液的界面活性

Gemini阴离子表面活性剂水溶液的界面活性;Gemini阴离子表面活性剂;表面张力;CMC;C20;界面张力     

The ultralow interfacial tensions between crude oils and gemini surfactant solutions

In this paper, the interfacial tension between crude oil and solution of cationic gemini surfactant has been studied. It is found that the interfacial tension between crude oil and water is closely related to the nature of a gemini surfactant and oil; meanwhile, in the case without additives, some gemini surfactants or mixtures of some gemini surfactants can reduce the interfacial tension between crude oil and water to an ultralow value.     

Interfacial activity of a novel family of polymeric surfactants

A novel series of polymeric surfactants based on carboxy methyl cellulose and alkyl poly(etheroxy) acrylate were synthesized by ultrasonic irradiation. These polymeric surfactants have exhibit excellent surface activity due to their unique structure. The influences of salt, alcohol and alkali on the interfacial activity of these polymeric surfactants were studied by interfacial tensiometery, dynamic laser scattering (DLS), UV spectroscope and environmental scanning electrical microscope (ESEM). The surface tension and interfacial tension (IFT) properties change little with NaCl added. The formed micelles shrink, their size becomes smaller. Alcohols cause the IFT to decrease a little because a small amount of free chains present in solution. Under the influence of added alkali, the IFT of the polymeric surfactants, in aqueous solution, decreases so much that sometimes it is less than 10⁻² mN/m. Using data from the equivalent alkane scan, one cannot draw the conclusion that the action of alkali with the acidic components in crude oil leads to the ultra-low IFT. The analyses by UV, DLS and ESEM show that the micelles formed by polymeric surfactants could be disaggregated or destroyed sharply by the action of alkali. So the size of micelles decreases greatly and the number of free chains increases. That more polymeric surfactants molecules move to the interface of oil/water and rearrange at the interface of oil/water is believed to be the main reason of the ultra-low IFT (10⁻³ mN/m) that is obtained.     

Ultra-Low Interfacial Tension Between Heavy Oil and Betaine-Type Amphoteric Surfactants

Betaine surfactants with lipophilic groups of different lengths were synthesized in this research and the dynamic interfacial tension (IFT) between solutions of these surfactants and three kinds of crude oil from Shengli Oilfield are measured. The results indicated that, for Gudao and Gudong heavy oil, cetyl dimethyl hydroxyl sulfobetaine (SBET-16) was the most efficient in lowering the IFT in the case of no alkalis, while for Shengtuo heavy oil, cetyl dimethyl carboxymethyl betaine (CBET-16) was best. SBET-16 with the concentration of 0.003–0.1% and 0.005–0.1% can reduce the oil/water IFT to ultra-low for Gudao and Gudong oil respectively, CBET-16 with the concentration of 0.005–0.1% can lower the oil/water IFT to ultra-low for Shengtuo oil. These results showed that for different oils, an oil displacement agent with high capacity to lower the oil/water interfacial tension may be obtained only by changing the molecular structure of betaine surfactant. This study can be used to guide the design of surfactants for alkaline-free combination flooding.     

Surfactants Synthesis Using Petroleum Fractions and Crude Oil: Application in Microemulsion Formulation

Surfactant synthesis was realized from Algerian crude oil and petroleum fractions. To predict the composition (wt%) in paraffins, naphtenes, and aromatics, the crude oil and petroleum fractions were first characterized using the n-d-PA empirical method of Robert. The characterization showed a good level in aromatics compounds which give high yield in the sulfonation reaction by oleum. The synthesized surfactants were characterized by spectroscopic techniques (UV, FTIR) and by critical micelle concentration (CMC), Krafft temperature, solubility (in aqueous and in salt solution), molecular weight, and matter actives (%) measurements. The formulation of microemulsion using synthesized surfactant from plat format petroleum fraction showed a Winsor III type system. The effect of salinity demonstrates the existence of an optimal value of NaCl concentration for which the interfacial tension takes the lowered value (10^?4 mN/m). Viscosity measurements confirm that the formulated microemulsion has a Newtonian behavior.     

高盐油藏下两性/阴离子表面活性剂协同获得油水超低界面张力

研究了在高盐油藏中, 利用两性/阴离子表面活性剂的协同效应获得油水超低界面张力的方法. 两性表面活性剂十六烷基磺基甜菜碱与高盐矿化水具有很好的相容性, 但在表面活性剂浓度为0.07%-0.39%(质量分数)范围内仅能使油水界面张力达到10^-2 mN·m^-1量级, 加入阴离子表面活性剂十二烷基硫酸钠后则可与原油达到超低界面张力. 通过探讨表面活性剂总浓度、金属离子浓度、复配比例对油水动态界面张力的影响, 发现两性/阴离子表面活性剂混合体系可以在高矿化度、低浓度和0.04%-0.37%的宽浓度范围下获得10^-5 mN·m^-1量级的超低界面张力, 并分析了两性/阴离子表面活性剂间协同获得超低界面张力的机制.     

Improving performances of double-chain single-head surfactants for SP flooding by combining with conventional anionic surfactants

The binary surfactant mixtures of 1,3-dialkyl (diC₈-diC₁₂) glyceryl ether ethoxylates with didodecylmethylhydroxylpropyl sulfobetaine (diC₁₂HSB) are good formulations for surfactant–polymer flooding of Daqing crude oil, China, but suffer from low aqueous solubility. By combining with α-olefin sulfonates (AOS) at small molar fractions, the aqueous solubility of the formulations can be significantly improved due to the formation of charged mixed micelles. The ternary formulations can reduce Daqing crude oil/connate water interfacial tension to ultralow at a wide range of total surfactant concentration (0.625?～?10?mM), have good resistance to adsorption by sandstone, and can keep sandstone surface water-wet.     

阴阳离子表面活性剂体系超低油水界面张力的应用

通过阴阳离子表面活性剂复配,在实际油水体系中获得了超低界面张力.通过在阴离子表面活性剂分子结构中加入乙氧基(EO)链段,以及采用阴阳离子加非离子型表面活性剂的三组分策略,有效解决了混合表面活性剂在水溶液中溶解度问题.进而研究了阳离子表面活性剂结构、非离子表面活性剂结构、三者组分配比、表面活性剂总浓度等因素对油水界面张力的影响,从而在胜利油田多个实际油水体系中获得了较大比例范围和较低浓度区域的油水超低界面张力,部分体系甚至达到了10-4 mN·m-1.由于阴阳离子表面活性剂间强烈的静电吸引作用,相关体系具有很好的抗吸附能力.经过石英砂48 h吸附后,体系仍然具有很好的超低界面张力.     

Synthesis and Performance of Novel Sulfonate Gemini Surfactant with Trialkyl Chains

A new type of sulfonate gemini surfactant with three lipophilic alkyl chains (3C₁₀-DS) was synthesized, and the structure of the product was confirmed by using the infrared spectrum and mass spectrum. Its critical micelle concentration (CMC) is 0.41 mmol/L, one order of magnitude lower than those of convectional (single-chain) surfactants, and the minimum surface tension is 27.6 mN/m. The interfacial tension (IFT) between the compound system of 3C₁₀-DS and petroleum sulfonate (PS) and the simulated oil reaches ultra-low levels (10^?3 mN/m), and there exists significant synergistic effect between 3C₁₀-DS and PS. The compound flooding system consisting of polymer and the mixture of 3C₁₀-DS and PS can effectively improve oil recovery for high-medium permeability cores and have a good application prospect in enhancing oil recovery.     

Comparative Analysis of the Properties of Tween‐20, Tween‐60, Tween‐80, Arlacel‐60, and Arlacel‐80

Foamability and foam stability, emulsifying power, surface tension, and interfacial tension were investigated for Tween‐20 (polyoxyethylene sorbitan monolaurate), Tween‐60 (polyoxyethylene sorbitan monostearate), Tween‐80 (polyoxyethylene sorbitan monooleate), Arlacel‐60 (Sorbitan stearate), and Arlacel‐80 (Sorbitan oleate). Among all the surfactants tested for their foaming power and foamabilty, Arlacel‐60 and Arlacel‐80 showed the best results; the foaming power and foamability was found to be 100%. The surfactants having foam stability more than 50% can be considered as metastable and those less than 50% are considered as low‐stability foams. In case of surface tension and interfacial tension property measurements, Arlacel‐80 showed the best results. At 1% surfactant concentration, the surface tension and interfacial tension of Arlacel‐80 was found to be 29.9 dynes/cm and 1.1 dynes/cm at 30°C ambient temperature. Also, Arlacel‐60 was found to exhibit the best emulsifying power among all the surfactants tested. At 30°C, the emulsifying property of Arlacel‐60 was 6 hours.     

正负离子混合表面活性剂双水相界面张力的研究

用旋转滴法测定了正负离子混合表面活性剂形成的双水相界面张力, 研究了双水相界面张力与表面活性剂的分子结构、正负离子表面活性剂的摩尔比、总浓度、外加无机盐及温度的关系. 结果表明, 双水相界面张力在一定正、负离子表面活性剂的摩尔比时属于超低界面张力范围. 观察到三种界面张力曲线类型, 第一类为摩尔比1:1 的两边的两条曲线, 界面张力随过剩表面活性剂组分的比例增加而降低; 第二类为一条跨过摩尔比1:1的马鞍型曲线; 第三类为位于摩尔比1:1的一边的一条马鞍型曲线. 界面张力曲线的类型主要取决于表面活性剂的分子结构, 包括亲水基类型、疏水链长度及对称性.     

Synergistic effect of mixed anionic and cationic surfactant systems on the interfacial tension of crude oil-water and enhanced oil recovery

Surfactant based enhanced oil recovery (EOR) is an interesting area of research for several petroleum researchers. In the present work, individual and mixed systems of anionic and cationic surfactants consisting of sodium dodecyl sulphate (SDS) and cetyltrimethylammonium bromide (CTAB) in different molar ratios were tested for their synergistic effect on the crude oil-water interfacial tension (IFT) and enhanced oil recovery performance. The combination of these two surfactant systems showed a higher surface activity as compared to individual surfactants. The effect of mixed surfactant systems on the IFT and critical micellar concentration (CMC) is strongly depends on molar ratios of the two surfactant. Much lower CMC values were observed in case of mixed surfactant systems prepared at different molar ratios as compared to individual surfactant systems. The lowest CMC value was found when the molar concentration of SDS was higher than the CTAB. When the individual and mixed surfacant systems were tested for EOR performance through flooding experiments, higher ultimate oil recovery was obtained from mixed surfactant flooding compared to individual surfactants. Combination of SDS and CTAB or probably other anionic-cationic surfactants show synergism with substantial ability to reduce crude oil water IFT and can be a promising EOR method.     

Synthesis of a new sulfobetaine surfactant with double long alkyl chains and its performances in surfactant-polymer flooding

A new zwitterionic surfactant with double long alkyl chains, 3-((3-((1,3-bis (decyloxyl) propane-2-yl) oxy) -2-hydroxypropyl) dimethylamonio) -2-hydroxypropane-1-sulfonate (diC₁₀GE-HSB), was synthesized, and its performances in Surfactant-Polymer (SP) flooding were studied. As a hydrophobic surfactant diC₁₀GE-HSB solely cannot reduce Daqing crude oil/connate water IFT to ultralow, but ultralow IFT can be achieved by using binary mixtures of diC₁₀GE-HSB with various conventional hydrophilic surfactants such as α–olefin sulfonates, dodecyl polyoxyethylene (10) ether, and cetyl dimethyl hydroxypropyl sulfobetaine, over a wide total concentration range (0.625?～?10?mM) at reservoir temperature. This new sulfobetaine surfactant is therefore a good candidate for SP flooding free of alkali.     

Molecular Dynamics Simulations of Sulfobetaine-Type Zwitterionic Surfactant at the Decane/Water Interface

Automated Topology Builder (ATB) and GAMESS (US) were used to build the model of a new sulfobetaine-type zwitterionic surfactant. And a serious of molecular dynamics simulations of the new sulfobetaine-type zwitterionic surfactant were performed at the decane/water interface by GROMACS, the influence of surfactant structure to the interfacial properties was investigated. The results show that the surfactant molecules can adsorb at the decane/water interface closely and reduce the interfacial tension significantly between decane and water. In another word, the model of the sulfobetaine-type zwitterionic surfactant is correct. The minimum interfacial tension could reach up to 1.6 mN · m^?1 when the number of surfactants was up to 134, which corresponds to the critical micelle concentration and consistent with the experimental values of the system.