黏弹性表面活性剂及其在油田中的应用

介绍了黏弹性表面活性剂溶液的性质，确定黏弹性表面活性剂性质的测试方法和实验手段，以及其内部微观结构和流变特性等方面的研究成果。当黏弹性表面活性剂溶液浓度增加到某一临界浓度时，球形胶束开始向蠕虫状胶束转变，溶液黏度突然增大，随着浓度的进一步增大，蠕虫状胶束快速生长、增长并形成线型柔性棒状胶束，柔性棒状胶束相互缠绕、粘附甚至融合，形成某种超分子三维网状结构，溶液黏度急剧增加，并表现出较强的黏弹性。概述了黏弹性表面活性剂在油田中的应用，特别是在压裂液、酸液、钻井液及提高采收率等方面的应用，指出了黏弹性表面活性剂广泛运用的前景和尚未解决的问题。     

Gemini表面活性剂黏弹性流体的流变性研究

C16-4-C16阳离子Gemini表面活性剂在NaCl和NaSal两种盐的作用下,可以形成蠕虫状胶束的黏弹性流体。采用流变仪研究了浓度、温度、剪切速率、剪切时间等因素对该流体黏度的影响,结果表明,2wt%的C16-4-C16流体在120℃下的零剪切黏度仍可达60mPa·s以上,而在80℃、170s~(-1)下剪切2 h黏度维持160mPa·s基本不变,说明该流体具有较强的耐温耐剪切性。触变实验的结果清楚地显示出该流体在不同的剪切作用下,蠕虫状胶束的形成与破坏是个可逆的过程。蠕虫状胶束间相互缠绕形成的网络结构,使流体具备了优异的黏弹性,高频有利于胶束储存能量,展现弹性形变;随着温度的升高,体系由弹性为主逐渐转变成了黏性较高的黏弹体,在60℃下黏性和弹性相当,展现了理想的Maxwell黏弹性流体的行为。     

纳米SiO_2对磺酸盐Gemini表面活性剂溶液性能的影响

通过对磺酸盐型Gemini表面活性剂加入纳米SiO_2,探究纳米SiO_2对其黏度、耐温性和粘弹性的影响,并从微观结构进行探究。结果表明,质量分数4%的DS18-3-18溶液黏度随着温度升高而降低。在复配体系中,随着纳米SiO_2质量分数增加,溶液黏度先增加后降低,其中质量分数在0.02%增黏效果最好,体系黏度从2.61 mPa·s增加到16.72 mPa·s,提高6.4倍,同时加入纳米SiO_2可以提高溶液的粘弹性。微观结构表明,温度升高,溶液微观结构胶束之间排列越来越稀疏,加入纳米SiO_2溶液微观结构变得紧密。     

纳米SiO_2对磺酸盐Gemini表面活性剂溶液性能的影响

通过对磺酸盐型Gemini表面活性剂加入纳米SiO_2,探究纳米SiO_2对其黏度、耐温性和粘弹性的影响,并从微观结构进行探究。结果表明,质量分数4%的DS18-3-18溶液黏度随着温度升高而降低。在复配体系中,随着纳米SiO_2质量分数增加,溶液黏度先增加后降低,其中质量分数在0.02%增黏效果最好,体系黏度从2.61 mPa·s增加到16.72 mPa·s,提高6.4倍,同时加入纳米SiO_2可以提高溶液的粘弹性。微观结构表明,温度升高,溶液微观结构胶束之间排列越来越稀疏,加入纳米SiO_2溶液微观结构变得紧密。     

十四烷基三甲基溴化铵蠕虫状胶束的形成及其线性黏弹性

以阳离子表面活性剂十四烷基三甲基溴化铵(TTAB)溶液作为反应主剂,油酸钠(NaOA)溶液作为反应助剂,制备得到了TTAB/NaOA蠕虫状胶束,并研究了表面活性剂摩尔比、主剂质量分数对蠕虫状胶束线性黏弹性的影响。结果表明,当主剂TTAB与助剂NaOA的摩尔比为2.6∶1～4.6∶1,TTAB质量分数在7%～16%之间时,溶液中均有蠕虫状胶束形成。当主剂TTAB与助剂NaOA的摩尔比为4.2∶1,TTAB质量分数为14%时,零剪切黏度可达到最大值即为η₀=15 324 mPa·s,且溶液体系的平台模量G₀和弛豫时间τ_R也达到最大值,此时溶液体系中蠕虫状胶束长度最长,网络结构最为紧密,并呈现出良好的线性黏弹性。由上述溶液体系的实际Cole-Cole图表明本文探讨研究的蠕虫状胶束体系是符合麦克斯韦模型的线性黏弹性流体。     

磺酸盐型Gemini表面活性剂复配体系的黏度性质研究

对以溴代十四烷、乙二胺和1,3-丙磺内酯为原料合成的磺酸盐型Gemini表面活性剂的表面活性进行了评价。主要研究了不同碳链长度的季铵盐、无机盐和有机盐的加入,剪切时间以及温度对上述表面活性剂体系黏度性质的影响。结果表明,磺酸盐型Gemini表面活性剂的临界胶束浓度比相应的单链表面活性剂低1~2个数量级;当向质量分数为1%的磺酸盐型Gemini表面活性剂中加入季铵盐时,复配体系的黏度先增加后减少,且季铵盐的碳链越长,增黏效果越明显,复配体系的黏度最大可达245.5 m Pa·s,碳链的增长有助于蠕虫状胶束的形成;在磺酸盐型Gemini表面活性剂和十六烷基三甲基溴化铵(CTAB)的复配体系中,随着KCl,Na Cl以及水杨酸钠质量分数的增加,复配体系的黏度先增加后减少,其中KCl的增黏效果最为显著,当KCl的质量分数为0.12%,复配体系的黏度达到最大,为430.2 m Pa·s;在磺酸盐型Gemini表面活性剂/CTAB/KCl的复配体系中,随着剪切时间和温度的增加复配体系的黏度逐渐降低。     

黏弹性双子表面活性剂压裂液的制备及性能评价

考察了阴离子双子表面活性剂SA系列及水杨酸钠对阳离子双子表面活性剂SC-18溶液黏弹性的影响。黏弹性表面活性剂的基础配方为:1%SA-12+1%SC-18+0.5%水杨酸钠。该压裂液体系可满足井温小于100℃的低渗透油藏的压裂改造。该压裂液具有较好的抗剪切能力,170s~(-1)下剪切2h后,黏度保留率大于80%;破胶后黏度小于5 mPa·s,表明该配方具备优异的破胶性能;破胶后均无残渣;石英砂在压裂液的沉降速度满足压裂液性能要求。     

N,N′-双(十八烷基二甲基)-1,2-二溴化己二铵盐双子表面活性剂的合成及应用研究

以十八叔胺与1,6-二溴正己烷为原料合成了双子表面活性剂N,N'-双(十八烷基二甲基)-1,2-二溴化己二铵盐(C18-6-C18·2Br-)。产物经红外光谱(IR)、核磁共振氢谱(1HNMR)和元素分析进行了确证。通过表面张力法测定了C18-6-C18·2Br-和十八烷基三甲基氯化铵(1831)的临界胶束浓度,测试结果表明:C18-6-C18·2Br-具有较高的表面活性,其临界胶束浓度为2.13×10-5mol/L,γCMC为39.1 m N/m,C18-6-C18·2Br-的临界胶束浓度较1831低一个数量级。对C18-6-C18·2Br-和水杨酸钠、氯化钾组成的清洁压裂液体系进行了性能研究。结果表明:双子表面活性剂在较低浓度时可形成稳定耐高温的胶束,具有良好的耐剪切能力,在110℃、170 s-1下连续剪切60min,表观黏度依然保持在60 m Pa·s左右;破胶性能良好,压裂液遇到煤油和盐水后可迅速破胶,残渣几乎为零,可较大程度地减小对地层的伤害;岩心伤害实验说明该压裂液体系对地层的伤害较小。说明该压裂液是一种耐温性能良好、黏弹性较好的低伤害压裂液。     

多季铵盐表面活性剂的合成及流变性能研究

以二乙胺盐酸盐、环氧氯丙烷、长链烷基二甲基叔胺为原料,合成了3种多季铵盐表面活性剂CD3N-n(n=12,16,18,代表烷基链碳原子个数);测定了上述多季铵盐表面活性剂的表面活性,并研究了碳链长度、温度、浓度以及反离子对多季铵盐水溶液流变性的影响。结果表明,合成的多季铵盐水溶液的临界胶束浓度(cmc)分别为2.0×10-4,1.0×10-4和8.0×10-5mol/L,临界胶束浓度下的表面张力(γcmc)分别为39.05,37.45和34.12 m N/m,cmc和γcmc均随着烷基链长度的增加而减小;CD3N-18的增黏效果显著,溶液黏度随CD3N-18浓度的增大而增大,随温度升高和反离子的加入先增加后减小,反离子助剂氯化钾的增黏效果较好,而水杨酸钠有助于提升产品的耐温性。     

新型拟双子表面活性剂构筑的蠕虫状胶束及其pH和温度响应行为（英文）

将短链二元酸(丁二酸(SA)、戊二酸(GA)、己二酸(AA))和长链N-(3-(二甲基氨基)丙基)硬脂酰胺(C18N3N)以1∶2的摩尔比混合,通过静电相互作用,构筑了三种新型的拟双子表面活性剂。该过程无需复杂的合成。通过表面张力仪和流变仪测试了该系列表面活性剂的表面活性和流变性能。结果发现,2C18N3N/GA拟双子表面活性剂的cmc为4.60×10^-5 mol/L,该值远低于传统双子表面活性剂,说明构筑的拟双子表面活性剂2C18N3N/GA具有很强的胶束聚集能力,2C18N3N/SA和2C18N3N/AA体系也具有类似的特征。在浓度超过50 mmol/L时,该系列表面活性剂可形成蠕虫状胶束,溶液表现出黏弹行为,且黏弹溶液具有较好的耐温耐剪切性能。还考查了上述黏弹溶液的pH和温度响应性,发现体系pH为6.1时,溶液黏度很高,pH为4.0或9.3时,黏度下降。随着温度的升高,体系的黏度也会迅速增加。在60℃时,该体系的零剪切黏度可高达11 967.73 Pa·s。该表面活性剂制备简单,性能优良,拓展了新型表面活性剂的制备方法和应用范围。     

Effect of Sodium Salicylate on the Properties of Gemini Surfactant Solutions

In this paper, the effect of sodium salicylate on the solution properties of a gemini surfactant, butylidene-α, ω-bis (cetyl dimethyl ammonium bromide), was investigated through absorbance and dynamic light scattering (DLS) measurement, transmission electron microscope (TEM) observation, and rheology measurement. The DLS experiment showed that the average size of aggregates increases with the addition of sodium salicylate. The TEM experiment showed that the addition of sodium salicylate causes the change of the size and shape of aggregate. With the increase of the concentration of sodium salicylate, the viscosity of the gemini surfactant solution reaches a maximum value and the flow pattern of the gemini surfactant solution also undergoes a great change with a transition from a Newtonian fluid to a non-Newtonian fluid.     

Rheological Investigation of Wormlike Micelles Based on Gemini Surfactant in EG–Water Solution

The self‐assembly behavior of gemini surfactants in ethylene glycol (EG)‐water (5/95, v/v) mixed solvent was investigated by rheological measurements at 10 °C. The influence of molecular structure of the gemini surfactant and added hydrotrope on the solution properties was studied. Sodium salicylate (NaSal) showed stronger ability to induce 2‐hydroxyl‐propanediyl‐α,ω‐bis‐(dimethyldodecylammonium bromide), referred to as 12‐3(OH)‐12, to form wormlike micelles than sodium benzoate. Less NaSal is required to promote a sphere to rod transition and to reach the peak viscosity. Moreover, the concentrations of hydrotrope and gemini surfactant are both lower than conventional single‐chain surfactant systems to reach a comparable viscosity. The strong hydrophobicity of gemini surfactants and hydrotropes is responsible for the high efficiency in forming wormlike micelles in EG/water systems. The geometric structure of gemini surfactants also plays a vital role in self‐assembly into wormlike micelles. Dimethylene‐1,2‐bis‐(dodecyl dimethylammonium bromide), referred to as 12‐2‐12, shows absolute superiority over 12‐3(OH)‐12 in constructing wormlike micelles. The present study will be helpful for developing de‐icing fluids and anti‐freezing solutions, which need rheology control in EG‐aqueous medium at low temperature.     

Rheological behavior of mixed system of ionic liquid [C8mim]Br and sodium oleate in water

We report on the rheological behavior of wormlike micelles constructed by ionic liquid surfactant [C₈mim]Br (1-octyl-3-methylimidazolium bromide) and anionic surfactant sodium oleate (NaOA) in aqueous solution. The effects of surfactant composition, total surfactant concentration, added salts, and temperature were investigated. The prevailing surfactant effect at lower concentration and the leading cosolvent effect at higher concentration of [C₈mim]Br may be the main reasons for appearance of well-established maximum in key rheological parameters with variation of surfactant composition and total surfactant concentration. The Cole-Cole plots demonstrate that the systems (total surfactant concentration falls within 0.17–0.35 mol·L^-1 and molar ratio 0.33≤R≤0.50) fit the Maxwell’s mechanical model as linear viscoelastic fluid. The addition of NaBr or sodium salicylate decreases significantly the viscosity and the relaxation time of the wormlike micelle solution but cannot change the value of plateau modulus G₀. The present system has low rheological tolerance to temperature. The increase of temperature decreases the average contour length and viscosity of wormlike micelles and thus strengthens the relaxation progress of diffusion and weakens the relaxation progress of reptation. Increasing the temperature also decreases the value of plateau modulus G₀ and shifts the minimum value of the loss modulus G^″_min to higher frequencies.     

偶联阳离子表面活性剂和常用阴离子表面活性剂混合溶液的相分离和微观结构

The properties of aqueous two-phase system (ATPS) of mixed solution containing gemini cationic surfactant trimethylene-l,3-bis(dodecyldimethyl ammonium) bromide (12-3-12, 2Br-) and traditional anionic surfactant sodium dodecyl sulfate (SDS) with or without added salt have been studied. An ATPS is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic-anionic surfactant systems. In ATPS region, the lowest total concentration of surfactants varies with the mixing ratio of geminis to SDS. Photographs obtained from freeze-etching, negative-staining and transmission electron microscopy show that the microstructures of two phases are different from each other. Micelles and vesicles can coexist in a single phase. The addition of salts can change the phase diagram of ATPS. Furthermore, the added salts promote the aggregation of rod-like micelles to form coarse network structure that increase the viscosity of solutions. The negative ions of the added salts are the determining factor.     

添加剂对C_(1)2-2-C_(12)·2Br水溶液黏度的调节

利用流变仪测定了表面活性剂水溶液的黏度,研究了不同添加剂对季铵盐gemini表面活性剂C_(12)-2-C_(12)·2Br水溶液的黏度调节情况.实验结果表明,C_(12)-2-C_(12)·2Br在水溶液中可以形成较大的棒状胶团,加入头基长度不同的阳离子表面活性剂,由于头基间的静电排斥作用使混合胶团中形成分子对的几何堆积因子P减小,形成了球状胶团,使C_(12)-2-C_(12)·2Br水溶液的黏度降低,加入普通表面活性剂对C_(12)-2-C_(12)·2Br的黏度降低的能力和效率顺序为C_(12)TMABr>C_(12)TBABr>C_(12)TPABr>C_(12)TEABr.相反,加入与C_(12)-2-C_(12)·2Br带相反电荷的阴离子表面活性剂或者无机盐,由于头基之间的静电吸引作用和压缩双电层作用,使表面活性剂分子的几何堆积因子增大,造成黏度增加.     

Gemini Surfactants with Polymethylene Spacer: Supramolecular Structures at Solid Surface and Aggregation in Aqueous Solution

Aggregation of α,ω-bisammonium cationic gemini surfactants with a variable polymethylene spacer and two dodecyl chains has been studied on a solid surface and in aqueous solution. Scanning electron microscopy and dynamic light scattering with the time-resolved fluorescence quenching technique were used for the experiments on the solid surface and in aqueous solution, respectively. As the results from the scanning electron microscopy indicate, the morphology of supramolecular structures of gemini surfactants at the solid surface depends on the spacer length. In aqueous solution, gemini surfactants with spacers consisting of 4, 6, 8, 10, and 12 CH₂ groups form spherical micelles with diameters between 2 and 3.5 nm. Micelles of gemini surfactant with a short ethylene spacer show an increase in size up to 13 nm at the maximum concentration investigated. The aggregation number of micelles determined by time resolved fluorescence quenching was found to be in the range 14–25 for the spacer lengths from 6 to 12 CH₂ groups with only a moderate increase with surfactant concentration. For micelles of gemini surfactants with the short ethylene spacer, the increase of the aggregation number up to 50 at the maximum concentration was observed. The findings support micellar growth of gemini surfactants with short ethylene spacer.     

N,N'-双(十六烷基二甲基)-1,2-二溴化乙二铵盐的合成及黏度行为

采用溴代十六烷与N,N,N',N'-四甲基乙二胺为原料合成了双子表面活性剂———N,N'-双(十六烷基二甲基)-1,2-二溴化乙二铵盐(C16-2-C16.2Br-),通过单因素法考察了原料配比、反应温度和反应时间对目标产物收率的影响,确立最佳合成工艺为:溴代十六烷与N,N,N',N'-四甲基乙二胺摩尔比值为2.1,反应温度为80℃,反应时间为22 h,收率达87.6%。通过红外光谱和核磁共振氢谱对产物结构进行了表征。降低油/水界面张力的测试结果表明,C16-2-C16.2Br-具有很高的界面活性,在质量浓度为0.3 g/L时,仅需23 min即可将界面张力降低至2.6×10-3mN/m。对不同条件下产物水溶液黏度进行了测试,考察了溶液质量浓度、温度和剪切速率对C16-2-C16.2Br-水溶液黏度的影响。发现C16-2-C16.2Br-具有良好的溶液增黏性,随温度和剪切速率的升高,产物水溶液黏度呈现急剧下降后平稳的趋势,表现出优异的耐温耐剪切性能;通过Ostwald-de Wale幂律方程,得出流动指数n<0.6,表明产物属于典型的假塑性流体。     

Wormlike Micelles in Mixed Amino Acid‐Based Anionic Surfactant and Zwitterionic Surfactant Systems

The formation of wormlike micelles in aqueous solutions of an amino acid‐based surfactant, sodium lauroyl sarcosinate (LS) and a zwitterionic surfactant, cocamidopropyl betaine (CAPB) has been investigated. Holding the total concentration of LS and CAPB constant at 12 wt%, the synergistic effects of mass ratio of CAPB and LS and pH of the micelle solution on rheological behaviors of CAPB/LS micelles were studied. The viscosity of CAPB/LS micelle systems with a mass ratio from 4:8 to 9:3 increases to maximum values and then decreases as pH increases from 4.0 to 5.6. The maximum viscosity of the transparent CAPB/LS micelle solution is nearly 5500 mPa·s with a mass ratio of CAPB/LS = 8:4 at pH 5.10. It is suggested that the proper pH for CAPB and LS to form wormlike micelles should be close to the isoelectric point of the CAPB/LS solution. The results of thixotropy measurements show that the appropriate mass ratio of CAPB/LS can improve the stability of the network structure of wormlike micelles. In addition, viscosity curves of CAPB/LS wormlike micelles follow a nonlinear co‐rotational Jeffreys model, and the linear viscoelasticity of CAPB/LS wormlike micelles can be described by a linear viscoelastic Jeffreys model. The network of wormlike micelles is confirmed by Cryo‐TEM images.     

Rheological Properties of Wormlike Micelles Formed in Aqueous Systems of 3‐Alkoxy‐2‐hydroxypropyl Trimethyl Ammonium Bromides in the Presence of Sodium Octanoate

The rheological properties of aqueous systems composed of each of the four homologous cationic surfactants (3‐alkoxy‐2‐hydroxypropyl trimethyl ammonium bromides, C_nHTAB, n = 12, 14, 16 and 18) in the presence of an anionic surfactant, sodium octanoate (SO), have been studied by using steady state and frequency sweep rheological measurements. The effects of surfactant concentration, hydrophobic chain length and temperature were investigated. In C₁₄HTAB solution, the viscosity shows shear thinning in the concentration range of C_C14HTAB >320 mmol/kg. Addition of SO promotes the micellar growth and results in the generation of wormlike micelles. Zero‐shear viscosity (η₀) of the binary surfactant system exhibits a maximum point in the investigated concentration range, suggesting the interaction between C₁₄HTAB and SO molecules is strongest at the optimal ratio of C₁₄HTAB with SO. The decrease in viscosity was attributed to be the transition from entangled wormlike micelles to branching micelles after the maximum point, cryo‐TEM images revealed the changes in the structure of the wormlike micelles.     

Krafft Temperature,Critical Micelle Concentration,and Rheology of “Pseudo-Gemini” Surfactant Comprising Fatty Acid Soap and Bola-Type Quaternary Ammonium Salt

Bola-type quaternary ammonium salt can bridge with two fatty acid soaps through electrostatic attraction to form a pseudogemini surfactant, which enhances the solution viscosity. In this work, the effects of the building blocks (spacer and hydrophobic chain) of a pseudogemini surfactant on the Krafft temperature, critical micelle concentration, and rheological properties were investigated. The results revealed that the addition of bola-type salt obviously decreased the Krafft temperature of sodium stearate (C₁₈ONa), and a bola-type salt bearing a large benzene ring (Bola2be) was more effective than the one bearing an ethyl group (Bola2et) or a hydroxyethyl group (Bola2hy). When bola-type salt is mixed with fatty acid soap at a fixed molar ratio of 1:2, a pseudogemini surfactant forms in situ, and the viscosity of the solution is significantly enhanced by the formation of a worm-like micelle (WLM) network. The stronger the hydrophobicity of the bola-type salt or the tail of the fatty acid soap, the lower the critical overlapping and micelle concentrations, and the stronger is the ability to enhance viscosity. However, pseudogemini surfactants that use sodium stearate as a monomer show similar self-assembly abilities to those using sodium oleate as a monomer. In addition, the WLM formed by pseudogemini surfactants composed of Bola2be and sodium stearate or sodium oleate were liable to branch at high concentrations.