Effect of polar head surfactants on the demulsification of crude oil

Surfactants can act as demulsifiers to neutralize the stabilizing effect of natural emulsifiers in crude oil. Here, the effect of polar head group of surfactants with identical hydrophobic chain C₁₂ (SLES, SLS, C₁₂E₂₃, BKC, C₁₂E₇) on the demulsification of crude oil emulsion and its effect on water separation rate were studied at different temperature. The activation energy for destabilization was calculated. The results indicate that the rate of water separation increases with temperature and surfactant concentration. The emulsion destabilising activation energy decreases as the concentration of the surfactant increases. The Interfacial Tension (IFT) study showed that when the reduction in IFT was the highest, the water separation rate and efficiency achieved was the highest.     

Evaluation of Surfactants for the Cost Effective Enhanced Oil Recovery of Assam Crude Oil Fields

Based on a hierarchial methodology, the article presents the comparative efficacy of Vim commercial detergent for the purpose of surfactant enhanced oil recovery of Assam crude oil in Indian reservoirs. Suitable technical and economic indices were defined to explore the economic competence with other surfactants such as sodium dodecyl benzene sulfonate and sodium dodecyl sulfonate. It was evaluated that the detergent formulation provided the following performance characteristics: I_C = 13.43 mN/m.g/L surfactant solution, surfactant sustainability index = 3.88 × 10^?3 mN/m.$/L surfactant solution, cost ratio = 0.32 ? 0.52 $ surfactant/$ crude oil recovered and 14.7–15.1% tertiary recovery with respect to original oil in place. Further ultralow interfacial tension formulations were also achievable with the commercial detergent.     

季铵盐型Gemini 表面活性剂水溶液的表面和油-水界面特性

 用 DCAT-21型表面张力及接触角仪测定了不同结构的季铵盐型 Gemini 表面活性剂 C_n-s-C_n·2Br 溶液的表面张力和界面张力变化,为选择一种较好的表面活性剂作为驱油剂提供基础。结果表明,烷基链长n 均为12时,随联接基团数s 的增加,季铵盐型 Gemini 表面活性剂降低表面和界面张力能力减小。s 相同时,随着烷基链长n 增加,Gemini 表面活性剂的临界胶束浓度（CMC）减小。加入无机盐可以进一步降低 Gemini 表面活性剂的 CMC 值。季铵盐型 Gemini 表面活性剂的 CMC 值较类似结构的单链单头普通表面活性剂的 CMC 值低,且达到最低界面张力时的浓度比单链单头普通表面活性剂低2个数量级。Gemini表面活性剂的高表面活性主要由其特殊的分子结构所决定。     

Synthesis,interface activity and oil flooding experiment with an authentic sandstone microscopic model of cationic gemini surfactant

In this work, a series of cationic gemini surfactants with different hydrophobic tails were prepared and characterized by element analysis, IR spectra, and ¹H NMR spectra. The influencing factors of physic-chemical properties of these surfactants were carefully studied. The critical micelle concentration (CMC) of all the surfactants ranged from 3.87 × 10^?4 mol L^?1 to 8.97 × 10^?4 mol L^?1 and the values (γ_cmc) also ranged from 28.62 mN m^?1 to 34.07 mN m^?1 at CMC level by surface tension experiments. The consequences of the oil/water interface tension experiments indicated that all these prepared surfactants could lower oil/water interface tension to ultra-low with the combination of Na₂CO₃. C₁₂-2-C₁₂, and C₁₄-2-C₁₄ were chosen as the representative to evaluate the displacement efficiency in the oil flooding experiments using authentic sandstone microscopic model. The results showed that these surfactants could effectively improve the displacement efficiency by 10–20%.     

脂肪醇聚氧乙烯醚磺酸盐系列表面活性剂的协同效应

为满足高温、高盐油藏三次采油的需求,采用自制的脂肪醇聚氧乙烯醚磺酸盐(NNA)系列作为抗温、耐盐驱油表面活性剂,考察了脂肪醇聚氧乙烯醚磺酸盐系列表面活性剂复配前后原油 矿化水体系界面张力的变化,并讨论了其协同效应,并采用静态吸附实验考察了该系列表面活性剂的吸附性能。结果表明,随着NNA表面活性剂分子中氧乙烯链节数的增加,原油 矿化水体系的油 水界面张力最低值对应的矿化度向着高矿化度方向移动,当氧乙烯链节数适中时,可以获得超低油 水界面张力。同系列表面活性剂复配可以显著改善表面活性剂体系的界面活性,具有明显的协同作用。复配表面活性剂使油 水界面张力达到平衡值的时间大大缩短,拓宽了达到超低界面张力的表面活性剂质量分数范围（003%～015%）,耐盐性能也得到提高,使用单剂时耐盐能力在100 g/L以下,复配后耐盐能力达到100 g/L以上。同系列表面活性剂在油砂上的吸附规律相同,从而降低了表面活性剂被地层色谱分离的可能。     

Synthesis and Interfacial Behavior of Decyl Methylnaphthalene Sulfonate

Abstract

High purity decyl methylnaphthalene sulfonate (DMNS) surfactant was synthesized. The purity of product was determined by HPLC, and the structure was confirmed by IR, UV, and ESI-MS. The surface and oil-water interfacial activities of DMNS surfactant were studied. The effects of concentrations of the surfactant, alkali, and inorganic salt on the dynamic interfacial behavior of crude oil/Shengli Oil Field/surfactant oil flooding systems were studied, and comparitive studies of systems with strong and buffered alkali were also carried out. Results showed that DMNS surfactant possessed great capability and efficiency for lowering solution surface tension and oil-water interfacial tension. The critical micelle concentration (cmc) was 0.02% and the surface tension at this concentration was 31.61 mN.m^?1. At proper concentrations of the surfactant, alkali, and inorganic salt, the dynamic interfacial tension between the crude oil of the Shengli Oil Field and the surfactant oil flooding system reached a minimum value of 10^?5–10^?6 mN.m^?1 in a very short time (3–20 min) and maintained an ultra-low value (< 10^?2 mN.m^?1) for a long period of time (15–87 min). The crude oil/surfactant systems presented satisfactory interfacial behavior. DMNS has great potential to be used in enhanced oil recovery (EOR) with low cost and high efficiency.     

Experimental Investigation of Matricaria chamomilla Extract Effect on Oil-Water Interfacial Tension: Usable for Chemical Enhanced Oil Recovery

Recently, natural surfactants had been studied for chemical enhanced oil recovery as opposite to synthetic surfactants due to environmental problems associated with synthetic surfactants. In this study a new plant based natural surfactant, Matricaria chamomilla, is introduced. For this purpose, the interfacial tension values between natural surfactant solution and oil are measured by using the pendant drop method. The results show that Matricaria chamomilla decreased the oil-water interfacial tension values from 30.63 to 12.57 mN/m. Results confirm surface chemical activity of Matricaria chamomilla in comparison with other natural surfactants.     

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     

阴离子双子表面活性剂的油水界面张力

测定了阴离子双子表面活性剂8-4-8和12-4-12与不同油相间的界面张力,考察了不同油相和矿化度变化对油水界面张力的影响。结果表明,阴离子双子表面活性剂与不同油相的油水界面张力达到平衡的时间都比较短,界面张力稳定性较好;8-4-8在煤油的油水界面活性最好,而12-4-12在稀油的油水界面活性比混合油的好。矿化度增加(0~180 g/L)能有效降低阴离子双子表面活性剂的油水界面张力,说明阴离子双子表面活性剂8-4-8和12-4-12具有较好的耐盐性。     

Gemini Surfactant as a New “Green” Demulsifier for Treating Oilfield Emulsions

Abstract

Surface tension and interfacial tension (IFT) were the key factors asso- ciated with the stability of crude oil emulsion. Investigation of interfacial tension behavior related with the demulsification of crude oil emulsions can have a great impact on the development of crude oil demulsification processes and products. This article presents the surface and interface behaviors of Gemini surfactants (12-2-12, (12)-2-(12), (14)-2-(14)). The results indicated that (12)-2-(12) could exhibit higher surface and interface active properties. The demulsification efficiency and related factors were also discussed. It showed that as an environmentally friendly and safer demulsifier, Gemini surfactant could exhibit better demulsification efficiency.     

Evaluation of interfacial tension between ASP solution and crude oil from B oil field

The interfacial tension (IFT) between alkali-surfactant-polymer (ASP) solution and crude oil is an important parameter for evaluating the feasibility of the ASP flooding for an oil field. The IFT between six series of ASP solution and crude oil from B oil field were measured at 65°C. Each series of ASP solution was composed of NaOH or Na₂CO₃, one of the three kinds of surfactants (S1, S2, and S3), and polymer FT60. The concentration of FT60 and surfactant were 1500 and 2000 mg/L, respectively. The research results show that the IFT between ASP solution and crude oil is ultra-low in the NaOH-FT60-S2 series and NaOH-FT60-S3 series and the best concentration of NaOH is 4000 mg/L and 8000 mg/L, respectively. NaOH-FT60-S2 series is more suitable for B oil field. The IFT between ASP solution and crude oil is ultra-low in the Na₂CO₃-FT60-S2 series and the best concentration of Na₂CO₃ is 4000 mg/L.     

三季铵盐表面活性剂界面性能及驱油效果评价

在化学驱中,降低油水界面张力是表面活性剂驱油最基本的机理。三季铵盐表面活性剂因其特殊结构表现出更好的界面性能。针对已合成的三季铵盐,探讨了各因素对界面性能的影响,结果表明,纯三季铵盐溶液与长庆油区模拟油界面张力可达10-2mN/m,比常规活性剂低1～2个数量级,具有较好的耐盐、耐高温性;与阴离子活性剂α-烯烃磺酸盐复配后,界面张力可达10-4mN/m,表现出较好的协同效应。驱替实验结果表明,纯三季铵盐可降低低渗透岩心注入压力10.6%,提高采收率8.35%;与α-烯烃磺酸盐复配后,降压率为17.4%,岩心采收率提高了11.1%,降压和驱油效果更佳,这也表明界面张力越低,提高低渗透岩心采收率效果越好。     

新型甜菜碱型两性离子表面活性剂界面行为的分子动力学模拟

利用分子动力学模拟方法研究了新型系列甜菜碱型两性离子表面活性剂在辛烷-水体系的界面行为。结果表明,分子动力学模拟得到的该体系油-水界面张力值与实验值相符, 可以定性比较不同分子结构的甜菜碱型表面活性剂降低油-水界面张力的能力;不同温度下烷烃-水-甜菜碱型表面活性剂体系的油-水界面张力变化不大,具有良好的耐温性;加入不同量NaCl时,该体系的油-水界面张力保持稳定,表明甜菜碱型表面活性剂具有良好的抗盐能力。在分子层面上探讨表面活性剂构效关系对油-水界面张力的影响,可为三次采油中驱油用表面活性剂的筛选提供理论依据。     

Interfacial tensions of phenyltetradecane sulfonates for enhanced oil recovery upon the addition of fatty acids

Producing ultra-low interfacial tensions is one of the most important mechanisms relating to surfactant flooding for enhanced oil recovery. Most crude oils contain organic acids, so it is of great significance to study the effects of fatty acids on the interfacial tensions of surfactant systems. The dynamic interfacial tension behavior of three surfactant systems, 1-phenyltetradecane sulfonate (1-PTDS), 3-phenyltetradecane sulfonate (3-PTDS) and 5-phenyltetradecane sulfonate (PTDS), were researched upon the addition of fatty acids to oil phase, n-octane. It has shown that the interfacial activity of surfactants and their ability of adsorption into interface control the dynamic interfacial tensions between aqueous solutions and oil phase. The interfacial tensions of 1-phenyltetradecane sulfonate decrease upon the addition of fatty acids, that of 3-phenyltetradecane sulfonate increase or do not change and that of 5-phenyltetradecane sulfonate increase. When mixed at appropriate concentrations and ratios, phenyltetradecane sulfonates and fatty acids could produce synergism for obtaining lower interfacial tensions. This study may be helpful in accounting for the cause of producing ultra-low interfacial tensions and for preparing formulations of practical application.     

无机盐对Gemini表面活性剂性质的影响及其协同效应研究

利用1,3-二溴丙烷和烷基碳数为C12～C18长链叔胺合成了3种Gemini阳离子表面活性剂,对其纯度和熔点进行了测定,采用电导率法测定了临界胶团浓度（Cmc）,研究了无机盐（NaCl、CaCl2、AlCl2）对3种Gemini阳离子表面活性剂的Cmc的影响,以及Gemini阳离子表面活性剂和十二烷基硫酸钠（SDS）的相互作用。试验结果表明,无机盐对Cmc影响较大,随着盐浓度增加,Cmc先降低后增加,而且三价Al^3＋比一价Na^＋的影响更大;合成的3种阳离子活性剂与SDS均有很好的协同作用,尤其是代号为C16-3-C16的相互作用更强,高活性的Gemini表面活性剂易于进入胶团中。     

Biodegradation of Used Engine Oil by a Methylotrophic Bacterium,Methylobacterium Mesophilicum Isolated from Tropical Hydrocarbon-contaminated Soil

A Gram-negative facultatively methylotrophic bacterium putatively identified as Methylobacterium mesophilicum strain RD1 displayed extensive degradative ability on used engine oil (SAE 40W) in liquid cultures. The rate of degradation of used engine oil (1274.85 mg L^?1) by the isolate, for the first 12 days and the last 9 days were 65 and 40 mg L^?1 d^?1, respectively. Gas chromatographic (GC) analyses of residual used engine oil revealed that 61.2% and 89.5% of the initial concentration of the used engine oil were degraded within 12 and 21 days. GC fingerprints of the used engine oil after 12 days of incubation showed total disappearance of C₁₅, C₂₃, C₂₄, C₂₅, and C₂₆ hydrocarbon fractions as well as drastic reductions of C₁₃, C₁₄, C₁₆, and PAHs fractions such as C₁₉-Anthracene and C₂₂-Pyrene. At the end of 21 days’ incubation, total disappearance of C₁₇-pristane, C₂₂-pyrene, one of the C₁₉-anthracene, and significant reduction of C₁₈-phytane (96.8%) fractions were observed. In addition, less than 10% of Day 0 values of medium fraction ranges C₁₃, C₁₄, and C₁₆ were discernible after 21 days. This study has established the potential of Methylobacterium mesophilicum strain RD1 in degradation of aliphatic, aromatic, and branched alkane components of used engine oils.     

SP二元复合驱提高重质原油驱油效率室内实验研究

针对NB35—2块重质原油油藏特点、开发现状及油品性质,开展了聚合物／表面活性剂（SP）二元复合驱提高驱油效率、改善水驱开发效果室内实验研究。对不同类型表面活性剂与水的配伍性、与原油问的界面活性、抗盐性、长期热稳定性和驱油效果进行了考察,结果表明,筛选的SP二元复合驱油体系为：0．10％聚合物＋0．36％表面活性剂17^#,溶液黏度19．7mPa·s,与原油间界面张力达10^-3mN／m数量级以下;注入0．3PV可提高驱油效率32．35％。     

A New Type of Surfactant for Enhanced Oil Recovery

abstract

Most naturally fractured reservoir rocks are mixed to oil wet and do not imbibe the injected water, which translates into low-efficiency waterflood recovery. To enhance the spontaneous imbibition process, a low concentration of surfactants is dissolved into the injected water to induce wettability alteration of the reservoir rock by changing the wettability of the rock toward a more water-wet state. Zizyphus spina-christi leaves, which are grown in the Middle East, produce a special surfactant called saponin. This surfactant can be used for chemical flooding in Iranian oil fields due to its low cost and availability. Saponin was extracted from leaves using a spray-drying method and the interfacial tension (IFT) between saponin–water–oil was determined. For interfacial tension measurements the pendant drop method was used. A typical pendant drop apparatus is presented in this article. The algorithms used to infer interfacial tension from the geometrical profile of the pendant drop are described in detail; in particular, a new method for evaluation of the value of the radius at the apex of the drop, necessary for calculation of interfacial tension, is presented. Saponin caused a reduction in interfacial tension from 48 to 9 dyn/cm, which can be decreased to ultralow IFT by the addition of salt and alcohol. According to the results, saponin can be used as a surface-active agent for enhanced oil recovery.     

表面活性剂增效碱驱中表面活性剂之间的协同效应

本文考虑了在碱（Ｎａ２ＣＯ３）性条件下表面活性剂之间在界面张力性质、耐盐性及驱油效率等方面的协同效应。实验结果表明，阴离子表面活性剂（石油磺酸盐）与非离子表面活性剂之间的复配，除在界面张力性质方面显现出比石油磺酸盐之间更好的协同效应外，石油磺酸盐在较高矿化度下的溶解性也获得根本改善，能够顺利通过孔隙介质并获得较高的驱油效率，长期放置亦无沉淀发生，为热力学稳定体系。