A Review of Gemini Surfactants: Potential Application in Enhanced Oil Recovery

Gemini surfactants are a group of novel surfactants with more than one hydrophilic head group and hydrophobic tail group linked by a spacer at or near the head groups. Unique properties of gemini surfactants, such as low critical micelle concentration, good water solubility, unusual micelle structures and aggregation behavior, high efficiency in reducing oil/water interfacial tension, and interesting rheological properties have attracted the attention of academic researchers and field experts. Rheological characterization and determination of the interfacial tension are two of the most important screening techniques for the evaluation and selection of chemicals for enhanced oil recovery (EOR). This review deals with rheology, wettability alteration, adsorption and interfacial properties of gemini surfactants and various factors affecting their performance. The review highlights the current research activities on the application of gemini surfactants in EOR.     

Gemini表面活性剂的特性及耐盐活性研究

研究了疏水链长度不同和联接基长度不同的7种系列阴离子Gemini表面活性剂的表/界面活性。它们的表面张力和临界胶束浓度表明它们有很好的表面活性。它们有非常好的抗一价、二价盐的能力,在20%以上的NaCl盐水中仍能溶解。用高矿化度的中原油田盐水配制的活性剂溶液与原油间的界面张力能达到超低,表明它们可应用于特高矿化度油藏提高采收率。     

A New Series of Double-Chain Single-Head Sulfobetaine Surfactants Derived from 1,3-Dialkyl Glyceryl Ether for Reducing Crude Oil/Water Interfacial Tension

A new series of sulfobetaine surfactants with double-chain single-head structure were derived from 1,3-dialkyl glyceryl ethers and their performances in reducing Daqing crude oil/connate water interfacial tension (IFT) in the absence of alkali were studied. With a large hydrophilic head group and double hydrophobic chains, these surfactants are efficient at reducing crude oil/connate water IFT. Those with didecyl and dioctyl are good hydrophobic surfactants that can reduce Daqing crude oil/connate water to ultra-low IFT by mixing with a small molar fraction of various conventional single-chain hydrophilic surfactants, such as α-olefin sulfonates, dodecyl polyoxyethylene (10) ether, and cetyl dimethyl hydroxypropyl sulfobetaine. The asymmetric double-chain sulfobetaine derived from 1-decyl-3-hexyl glyceryl ether can reduce Daqing crude oil/connate water IFT to ultra-low solely over a wide concentration range (0.03–10 mM or 0.0017–0.58 wt.%), which allows for use of an individual surfactant instead of mixed surfactants to avoid chromatographic separation in the reservoir. In addition, formulations rich in sulfobetaine surfactants show low adsorption on sandstone, keeping the negatively charged solid surface water-wet, and forming crude oil-in-water emulsions. These new sulfobetaine surfactants are, therefore, good candidates for surfactant-polymer flooding free of alkali.     

Enhanced oil recovery from high‐salinity reservoirs by cationic gemini surfactants

In order to enhance oil recovery from high‐salinity reservoirs, a series of cationic gemini surfactants with different hydrophobic tails were synthesized. The surfactants were characterized by elemental analysis, infrared spectroscopy, mass spectrometry, and ¹H‐NMR. According to the requirements of surfactants used in enhanced oil recovery technology, physicochemical properties including surface tension, critical micelle concentration (CMC), contact angle, oil/water interfacial tension, and compatibility with formation water were fully studied. All cationic gemini surfactants have significant impact on the wettability of the oil‐wet surface, and the contact angle decreased remarkably from 98° to 33° after adding the gemini surfactant BA‐14. Under the condition of solution salinity of 65,430 mg/L, the cationic gemini surfactant BA‐14 reduces the interfacial tension to 10^?3 mN/m. Other related tests, including salt tolerance, adsorption, and flooding experiments, have been done. The concentration of 0.1% BA‐14 remains transparent with 120 g/L salinity at 50 °C. The adsorption capacity of BA‐14 is 6.3–11.5 mg/g. The gemini surfactant BA‐14 can improve the oil displacement efficiency by 11.09%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46086.     

Characterizations of surfactant synthesized from Jatropha oil and its application in enhanced oil recovery

Surfactants are frequently used in chemical enhanced oil recovery (EOR) as it reduces the interfacial tension (IFT) to an ultra‐low value and also alter the wettability of oil‐wet rock, which are important mechanisms for EOR. However, most of the commercial surfactants used in chemical EOR are very expensive. In view of that an attempt has been made to synthesis an anionic surfactant from non‐edible Jatropha oil for its application in EOR. Synthesized surfactant was characterized by FTIR, NMR, dynamic light scattering, thermogravimeter analyser, FESEM, and EDX analysis. Thermal degradability study of the surfactant shows no significant loss till the conventional reservoir temperature. The ability of the surfactant for its use in chemical EOR has been tested by measuring its physicochemical properties, viz., reduction of surface tension, IFT and wettability alteration. The surfactant solution shows a surface tension value of 31.6 mN/m at its critical micelle concentration (CMC). An ultra‐low IFT of 0.0917 mN/m is obtained at CMC of surfactant solution, which is further reduced to 0.00108 mN/m at optimum salinity. The synthesized surfactant alters the oil‐wet quartz surface to water‐wet which favors enhanced recovery of oil. Flooding experiments were conducted with surfactant slugs with different concentrations. Encouraging results with additional recovery more than 25% of original oil in place above the conventional water flooding have been observed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2731–2741, 2017     

磺酸盐型低聚表面活性剂的合成研究进展

磺酸盐型低聚表面活性剂具有良好的界面活性及耐温抗盐等性能而广受国内外学者关注。本文基于亲油亲水基团的3种引入方法：单体联接法、疏水链加入法及极性头基加入法,重点综述了近十年来磺酸盐型低聚表面活性剂的合成,简要介绍了产物的表/界面张力、临界胶束浓度等物化性质以及乳化降黏、杀菌和驱油等应用性能。指出应注重产品结构与性能关系研究,通过分子设计开发性价比优异的新型磺酸盐低聚表面活性剂,优化合成工艺,加强与其它类型表面活性剂、聚合物组成的驱油体系研究,以实现其在三次采油中的工业应用。     

木素及衍生物在油田上的应用

木素磺酸盐及改性物在三次采油过程中，具有降低石油磺酸盐等阴离子型活性剂在岩石表面上的吸附损失、乳化原油，与石油磺酸盐产生协同效应，降低油、水界面张力，提高残余油回收效率的性能。介绍了木素碘酸盐的改性方法与用途。应用木素磺酸盐及改性物进行三次采油，对于有效地开采水驱残余油，降低表面活性剂驱油成本具有重要意义。     

Gemini表面活性剂的性质研究

Gemini表面活性剂通常是由两（或三）条疏水链、两个亲水基和一个连接基组成的两性分（离）子,与由单亲水基和单疏水链构成的传统表面活性剂分（离）子相比较,在临界胶团浓度、界面性质等方面有着独特的性质。详述了该类新型表面活性剂的性质,比较了与传统表面活性剂的差别。     

哌嗪系列双子表面活性剂的合成

为了探索哌嗪类双子表面活性剂在三次采油(EOR)、新材料制备及生物技术领域中的应用,合成了两个以哌嗪为基的双子表面活性剂Ⅰ和Ⅴ,一个含有两种阴离子的Bola型表面活性剂Ⅱ和一个大环表面活性剂Ⅲ。表面张力测定结果显示,Ⅰ的临界胶束浓度(CMC)为6.47×10-4mol/L,优于传统的表面活性剂;Ⅴ的CMC为1.17×10-3mol/L,说明连接基团长度一定时,增加疏水链的数目,表面活性降低。Ⅱ和Ⅲ水溶性较好,可应用于生物技术领域或在新材料中作为模板剂。MM2能量最小法计算结果显示,在有限长连接基团中引入较多疏水链的化合物不易合成。用溶剂可接触面积说明了Ⅲ水溶性较好的原因。     

硫酸酯盐双子表面活性剂的合成和界面张力的研究

实验室条件下,以长链羧酸(月桂酸)、聚乙二醇等为主要原料,通过赫尔-乌尔哈-泽林斯基反应等和酯化反应,用醚键加入方式加入联接基团,用浓硫酸加成反应加入硫酸酯键,从而在实验室条件下合成具有特殊结构的双子表面活性剂-GA12-S-12.通过用旋转液滴法测合成的硫酸酯盐阴离子双子表面活性剂的表面张力,测得其临界胶束浓度(CMC)为438 mg/L,临界胶束浓度下表面张力为30.9 mN/m,并对比十二烷基硫酸钠水溶液表面张力,显示GA12-S-12[低聚二醇(α-硫酸酯钠)月桂酸双酯阴离子双子表面活性剂]具有更优的表面活性.进一步配制不同浓度的GA12-S-12表面活性剂溶液,测定它们与长庆五里湾原油的界面张力,效果显示其适用于五里湾区原油采收率的提高.     

Gemini表面活性剂的吸附、自聚和性质

Gemini表面活性剂通常是由两 (或三 )条疏水链、两个亲水基和一个连接基组成的两性分(离 )子 ,与由单亲水基和单疏水基构成的单体表面活性剂分 (离 )子相比较 ,在临界胶团浓度、界面性质和溶解性等方面有着独特的性质。由于其电荷密度高 ,临界胶团浓度低 ,并且有很低的 Krafft点 ,能在低浓度下与高碳烷烃形成超低界面张力 ,在石油开发中有着很好的应用前景。详述了该类新型表活性剂的吸附、自聚、性质 ,比较了与单体表面活性剂的差别     

Surface Activity and Performance Properties of Gemini Salts of Linear Alkylbenzene Sulfonate in Aqueous Solution

Gemini salts of linear alkylbenzene sulfonate (LABS) were prepared by neutralization of sulfonic acid with a series of low-molecular-weight diamines in aqueous solution. The equilibrium surface activity of Gemini salts of LABS was determined by measuring the surface tension as a function of surfactant concentration to determine the critical micelle concentration (CMC), surface tension at the CMC (γ_CMC), and the area per molecule at the air-water interface (Ų). Electrical conductivity was measured as a function of surfactant concentration to determine the CMC and counterion binding. Dynamic surface tension was measured using a bubble pressure tensiometer to infer the rate at which the surfactant migrates to the air-water interface. Equilibrium interfacial tension against mineral oil was measured using a spinning drop tensiometer. Dynamic interfacial tension was measured using a drop volume tensiometer. The surface tension, CMC, and interfacial tension of Gemini salts of LABS decreased compared to monovalent organic and inorganic salts. The CMC decreases with increasing molecular weight of the diamine spacer group. Dynamic surface and interfacial tension of Gemini salts of LABS are lower than monovalent salts. The foam volume of Gemini salts of LABS was determined using a high shear blender test. The foam volume of Gemini salts of LABS is lower than monovalent salts and depends on the size of the spacer group. Hard-surface cleaning was measured using artificial soil applied to white Formica tiles. Soil removal was determined by optical reflectance as a function of abrasion cycles. Gemini salts of LABS show reduced hard-surface cleaning performance compared to monovalent salts. Detergency of different types of soils on cotton and polyester/cotton fabric was determined by optical reflectance measurements. Gemini salts of LABS show improved cleaning performance compared to monovalent salts. Cleaning performance increases with increasing molecular weight of the diamine spacer group. In situ neutralization of LABS with organic diamines is a simple and efficient way to prepare anionic Gemini surfactants for industrial scale applications.     

新型表面活性剂疏水缔合聚合物提高原油采收率的性能研究

介绍了渤海海上油田二元复合驱驱油的设计与开发方案,以新型表面活性剂(非离子型表面活性剂:DMES-14、TX-100)和疏水缔合聚丙烯酰胺(HAPAM)为主。二元复合驱驱油体系主要需要双子表面活性剂双十四酸乙二酯双磺酸盐型表面活性剂(DMES-14),疏水缔合聚丙烯酰胺以及取自海上油田平台的回注水。该体系同时对粘度和表面张力进行了研究。结果表明,该体系在不要求浓度的情况下可以达到超低界面张力2.48×10~(-3) m N/m,在油藏中粘度可达到55 m Pa;随后的岩心驱替试验表明,在水驱含水75%的状况下进行二元复合驱驱油效果可提高至38.6%以上。总之,该实验研究提供了非离子表面活性剂与疏水缔合水溶性聚合物驱油体系的实用信息以及可以在渤海海上油田进行大规模应用HAPAM。     

Synthesis of Bis[<Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-(alkylamideethyl)ethyl] Triethylenediamine Bromide Surfactants and Their Oilfield Application Investigation

Bis[N,N′-(alkylamideethyl)ethyl] triethylenediamine surfactants are quaternary ammonium salt Gemini surfactants with amide, which are synthesized from fatty acid (dodecanoic, hexadecanoic, tetradecanoic and octadecanoic) methyl esters, triethylene tetramine and ethyl bromide. The chemical structures of the prepared compounds were characterized by elemental analysis, FTIR and ¹H-NMR spectra, melting point and Krafft point. Several properties of the synthesized surfactants were studied including surface tension, critical micelle concentration, interfacial tension, emulsification power, salt effect, corrosion inhibition efficiency and biological activity. The results show that the surface activity, critical micelle concentration and interfacial activity are correlated to their chemical structures. The emulsification power measurements of these surfactants show their low emulsifying tendency towards Tazhong’s crude oil from Tarim Oilfield. The synthesized surfactants also exhibit high biocidal activity towards Gram-positive and Gram-negative bacteria and fungi. This activity increases with the increase of alkyl chain length. The corrosion measurement of these surfactants in acidic media with a weight loss technique show good protection of mild steel alloys against acidic environments. These properties suggest that the synthesized compounds have potential for application in the oilfield area.     

系列反应型阳离子Gemini表面活性剂的合成及性能

通过三步反应,以甲基丙烯酸二甲氨基乙酯(DM)、环氧氯丙烷(ECH)和3种长链烷基叔胺(十二烷基叔胺、十四烷基叔胺、十六烷基叔胺)为主要原料,合成了3种反应型阳离子Gemini 表面活性剂,即C₁₂-3(OH)-DM、C₁₄-3(OH)-DM和C₁₆-3(OH)-DM。利用傅里叶变换红外光谱仪(FTIR)、核磁共振仪(¹H NMR)和元素分析仪表征了目标产物结构,通过 DCTA21 表面界面张力仪测定其在水溶液中的表面张力、临界胶束浓度(cmc)以及其热力学常数,并测定了其水溶液的乳化性能和泡沫性能。结果表明:与传统单子季铵盐型表面活性剂相比,Gemini 表面活性剂C_m-3(OH)-DM(m=12,14,16)具有更高的表面活性,其临界胶束浓度(cmc)分别为 0.0265mmol/L、0.0169mmol/L、0.0083mmol/L,对应的表面张力γ_cmc分别为 32.1mN/m、30.1mN/m、27.7mN/m。     

Recent Advances in the Synthesis of Sulfonate Gemini Surfactants

Sulfonated Gemini surfactants are a relatively new class of anion surfactants, composed of 2 or more sulfonated surfactant monomers connected by a spacer at or near the head groups through a covalent bond. In general, the sulfonated Gemini surfactants show better properties compared to conventional anionic surfactants including better surface activity, a lower critical micelle concentration, enhanced detergency, excellent compatibility with other surfactants, and better solubility in high ionic strength systems. This article reviews the synthesis of the sulfonated Gemini surfactants using different raw materials. Based on the existing information in the literature, new ideas are proposed for the synthesis and application of the sulfonated Gemini surfactants.     

Mixed Micellar and Interfacial Interactions of a Triblock Polymer (EO37PO56EO37) with a Series of Monomeric and Dimeric Surfactants

The mixed micellar and interfacial properties of mixtures of triblock polymer (TBP) with a series of monomeric (dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, and cetyltrimethylammonium bromide, and dimeric (dimethylene bis[alkyldimethylammonium bromide], m-2-m, where m = 10, 12, and 14) cationic surfactants were investigated using surface tension and viscosity measurements in aqueous solutions at different temperatures. Various physicochemical properties such as critical micelle concentration, mixed micellar mole fraction, interaction parameter, interfacial, and thermodynamic parameters were evaluated. All the binary mixtures exhibit synergistic interactions which increase with temperature and pass through a minimum with the increase in hydrophobic chain length of the cationic surfactants. The contribution of TBP in mixed micelle formation also increases with the hydrophobic chain length of the surfactants. The interfacial and thermodynamic parameters reveal that the adsorption of the surfactant mixtures at the air–solution interface is more favorable than that of micelle formation and the unfavorable enthalpy changes are overwhelmed by favorable entropy changes. Further, the mixtures of TBP with smaller chain length surfactants show a sharp rise in relative viscosity at higher mole fractions of these surfactants.     

Novel alkyl methylnaphthalene sulfonate surfactants: A good candidate for enhanced oil recovery

The surface tensions of various surfactant aqueous solution and the dynamic interfacial tensions between the Shengli oil field of China crude oil and the solution of novel surfactants, a series of single-component alkylmethylnaphthalene sulfonates (AMNS) including various the length of alkyl chains (hexyl, octyl, decyl, dodecyl and tetradecyl, developed in our laboratory), were measured. It is found that synthesized surfactants exhibited great capability and efficiency of lowering the solution surface tension. The critical micelle concentrations, CMC were: 6.1–0.018×10⁻³ mol L⁻¹, and the surface tensions at CMC, γ_CMC were: 28.27–35.06 mN m⁻¹. It is also found that the added surfactants are greatly effective in reducing the interfacial tensions and can reduce the tensions of oil–water interface to ultra-low, even 10⁻⁶ mN m⁻¹ at very low surfactant concentration without alkali. The addition of salt, sodium chloride, results in more effectiveness of surfactant in reducing interfacial tension and shows that there exist obviously both synergism and antagonism between the surfactant and inorganic salt. All of the synthesized surfactants, except for hexyl methylnaphthalene sulfonate, can reduce the interfacial tension to ultra-low at an optimum surfactant concentration and salinity. Especially Tetradec-MNS surfactant is most efficient on lowering interfacial tension between oil and water without alkaline and the other additives at a 0.002 mass% of very low surfactant concentration. Both chromatogram separation of flooding and breakage of stratum are avoided effectively, in addition to the less expensive cost for enhanced oil recovery, and therefore it is a good candidate for enhanced oil recovery.     

Interfacial properties of cationic and anionic Gemini surfactant mixtures

The possibility and the prospect of cationic/anionic (“catanionic”) surfactant mixtures based on sulfonate Gemini surfactant (SGS) and bisquaternary ammonium salt (BQAS) in the field of enhanced oil recovery was investigated. The critical micelle concentration (CMC) of SGS/BQAS surfactant mixtures was 5.0 × 10⁻⁶ mol/L, 1–2 orders of magnitude lower than neat BQAS or SGS. A solution of either neat SGS or BQAS, could not reach an ultra-low interfacial tension (IFT); but 1:1 mol/mol mixtures of SGS/BQAS reduced the IFT to 1.0 × 10⁻³ mN/m at 100 mg/L. For the studied surfactant concentrations, all mixtures exhibited the lowest IFT when the molar fraction of SGS among the surfactant equaled 0.5, indicating optimal conditions for interfacial activity. The IFT between the 1:1 mol/mol SGS/BQAS mixtures and crude oil decreased and then increased with the NaCl and CaCl₂ concentrations. When the total surfactant concentration was above 50 mg/L, the IFT of SGS/BQAS mixtures was below 0.01 mN/m at the studied NaCl concentrations. Adding inorganic salt reduced the charges of hydrophilic head groups, thereby making the interfacial arrangement more compact. At the NaCl concentration was above 40,000 mg/L, surfactant molecules moved from the liquid–liquid interface to the oil phase, thus resulting in low interfacial activity. In addition, inorganic salts decreased the attractive interactions of the SGS/BQAS micelles that form in water, decreasing the apparent hydrodynamic radius (D_{H, app}) of surfactant aggregates. When the total concentration of surfactants was above 50 mg/L, the IFT between the SGS/BQAS mixtures and crude oil decreased first and then increased with time. At different surfactant concentrations, the IFT of the SGS/BQAS mixtures attained the lowest values at different times. A high surfactant concentration helped surfactant molecules diffuse from the water phase to the interfacial layer, rapidly reducing the IFT. In conclusion, the cationic-anionic Gemini surfactant mixtures exhibit superior interfacial activity, which may promote the application of Gemini surfactant.     

咪唑啉基季铵盐型双子表面活性剂的合成与性能

以环氧氯丙烷为连接剂,油酸、二乙烯三胺分别为疏水和亲水基团的初始原料合成了一种咪唑啉基季铵盐型双子表面活性剂,通过IR1、HNMR确证了目标产物结构。研究了其在水溶液中对苯的乳化力、稳泡能力、亲水亲油平衡值、表面张力的影响。动态激光散射法测试了双子咪唑啉基季铵盐乳化制备O/W型乳状液的乳胶粒径尺寸,利用双子表面活性剂作为乳化剂,油酸为分散相。静态失重法评价了双子表面活性剂作为缓蚀剂对Q235钢在质量分数8%溶液中的缓蚀性能。结果表明,所合成的双子咪唑啉基季铵盐具有较好的表面活性,临界胶束浓度CMC约为2×10-4mol/L,γCMC为31.40 mN/m,HLB值为14.2,对苯的乳化能力及稳泡性能良好。该乳液稳定,在25~50℃时,O/W乳液的胶粒尺寸在216~236 nm,是一种性能良好的O/W型乳化剂。失重法测定结果表明,该双子咪唑啉基季铵盐型表面活性剂缓蚀性能优于相应单链咪唑啉季铵盐表面活性剂。