Evaluation of Interfacial Tension Between SP Solution and Simsim Oil

Surfactant–polymer (SP) flooding has been proved to be an effective enhanced oil recovery method. Producing ultra-low interfacial tensions is an important mechanism relating to SP flooding for enhanced oil recovery. The interfacial tension between surfactant (PJS-1 and BE)/polymer solution and Simsim oil was evaluated in the work. The influence of surfactant and polymer concentration on interfacial tension between Simsim oil and these solutions is discussed. The interfacial tension between the oil and the surfactant solution reduces as the surfactant concentration increases. In the same concentration of surfactant, the interfacial tension between the surfactant solution and the oil becomes larger when the polymer was added in the solution.     

Recovery of residual oil using the alkali/surfactant/polymer process: effect of alkali concentration

An experimental study was conducted to examine the effectiveness of sodium carbonate in alkali, surfactant and polymer combined slugs in recovering waterflood residual oil. The effects of sodium carbonate concentration on the slug viscosity, interfacial tension, and phase behavior were first examined. Core flood experiments were conducted with unfired linear Berea sandstone cores. The incremental oil recovery, oil cut, residual resistance factor, and chemical propagation were measured for each flood.A significant oil bank was formed for all combined slugs having sodium carbonate concentration ≥1 wt%. The incremental oil recovery, oil cut and the injectivity of the combined slugs greatly improved as sodium carbonate concentration was increased. The effect of sodium carbonate concentration on chemical propagation was dramatic for the synthetic surfactant; a slight delay in surfactant breakthrough and a much slower rate of surfactant propagation were observed at high sodium carbonate concentrations.The results obtained in the present study indicate that the residual oil was recovered by two mechanisms: low interfacial tension and wettability reversal. The former mechanism is dominant at sodium carbonate concentrations ≤1 wt%, whereas the latter plays an important role only at high sodium carbonate concentrations.     

复合表面活性剂酸液助排剂FOC及其应用

测定分属4种类型的10余种常用表面活性剂的表/界面张力和润湿性(相对润湿角)。根据测试结果并考虑相互间的协同效应和价格,研发了由20%降低表面张力能力强的FSK(临界胶束浓度FSK水溶液的表面张力为25.3 mN/m)、40%降低界面张力能力强的CTAB(临界胶束浓度CTAB水溶液与煤油间的界面张力为2.0 mN/m)、10%可增加接触角的OP-10(1.6 g/L OP-10的20%盐酸溶液在石英砂上的接触角为69.1°)及辅助表面活性剂组成的高效助排剂FOC。FOC在酸液中与各种添加剂配伍,表/界面活性高,加入200 mg/L FOC的20%盐酸溶液的表面张力为26.3 mN/m,与煤油间的界面张力为2.1 mN/m,助排率为85.9%,热稳定性好。74低渗区块741313油井经检泵、洗井作业后受到严重水伤害,产出液含水100%,注入含0.5%FOC的前置液、8%盐酸及8%/2%土酸 5%醋酸后,含水降至51.6%,日产油恢复至4.8 t。图9表2参5。     

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.     

表面活性剂水溶液与油之间的动态界面张力研究

本文研究了两种表面活性剂(TRS10-80和天津ABS)盐水溶液与煤油之间的界面张力特性,提出了表面活性剂盐水溶液/煤油体系中动态界面张力产生的机理,讨论了表面活性剂对油的增溶作用对界面张力的影响。经过长期预平衡的表面活性剂盐水溶液/煤油体系仍然存在明显的功态界面张力特性。     

A lysine amino acid-based surfactant: Application in enhanced oil recovery

Surfactants can play major role in increasing oil recovery factor through interfacial tension reduction. In the present study, a new synthetic method was used to prepare (S)-2-amino-6-dodecanamidohexanoic acid, an amino acid–based surfactant then it was applied as an oil recovery agent for the first time. The structure of this surfactant was studied using FTIR and ¹H NMR spectroscopy. The critical micelle concentration was found to be value is 0.4–0.5 wt% using surfactant solution conductivity, pH, and IFT methods. A 56.50% reduction of IFT was recorded using this environmentally friendly surfactant.     

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.     

Interfacial activity of alkyl hydroxyl sulfobetaine against crude oil

To study the interfacial activities of zwitterionic surfactant against crude oil, four alkyl hydroxyl sulfobetaines were synthesized. The effects of surfactant structure, concentration, salinity of formation water, and crude oil composition on interfacial activities were discussed. It shows that the octadecyl hydroxyl sulfobetaine can achieve ultralow interfacial tension at the concentrations no less than 0.001%, exhibiting a good interfacial activity and a very strong antidilution ability. The salinity of formation water has no obvious effect on lowering the interfacial tension and the polar component in crude oil is very crucial for the production of ultralow interfacial tension. This work is important for enhanced oil recovery.     

The effects of interfacial tension,injection rate,and permeability on oil recovery in dilute surfactant flooding

Surfactant flooding as a potential enhanced oil recovery technology in depleted reservoirs after water flooding has been documented for several decades and has attracted extensive attention. This research explored the effect of interfacial tension among crude oil and surfactant, injection rate, and permeability on oil recovery in dilute surfactant flooding. The results indicated that the additional oil recovery increased with the reduction of the interfacial tension and the increase of the permeability. The additional oil recovery increased and later decreased with the increase of injection rate. The research is instructive for surfactant flooding application for enhanced oil recovery.     

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.     

桩西115区块表面活性剂驱技术研究与应用

胜利油田桩西采油厂桩115区块属于高温中低渗油藏,为进一步改善区块注采矛盾,本文通过考察不同浓度4种甜菜碱表面活性剂溶液与桩115区块原油间的界面张力及其在石英砂表面的吸附规律,开发了以甜菜碱表面活性剂为主剂、以碱木素为牺牲剂的低界面张力驱油体系。该体系在石英砂表面的静态吸附量为0.4 mg/g;无需同碱复配,即可使油水界面张力降至5×10-4mN/m。物理模拟实验表明,在水驱后注入0.3 PV冻胶堵剂+0.3 PV低界面张力驱油体系,原油采收率可提高17%。2008年1月在桩115-5井组采用驱替方案进行了现场试验,截止2010年5月净增原油1632 t。图13参7     

锦州油田无碱二元复合驱实验研究

针对锦州油田的条件及开采现状,进行了α-烯烃磺酸盐类表面活性剂HDS及SNF聚合物组成的二元复合体系(SP)提高采收率的室内研究。考查了HDS表面活性剂的界面张力特性以及吸附特征;进行了二元复合体系的界面张力、表观黏度及岩心驱替等实验。结果表明:HDS表面活性剂油水平衡界面张力可以降低到超低数量级(10-3mN/m),吸附损失小(0.2%浓度HDS≤2.0 mg/g);二元复合体系油水平衡界面张力也能达到超低;黏度保持率高(≥90%),配伍性好,相对水驱提高采收率20%以上。故HDS表面活性剂是性能优良的表面活性剂,HDS与SNF聚合物组成的无碱二元复合体系能大大提高锦州油田的采收率,无碱二元复合驱是适合锦州油田开发的新技术。     

阴离子双子表面活性剂的油水界面张力研究

为探究GA系列新型阴离子双子表面活性剂的油水界面活性及提高油层原油采收率的可行性,以模拟地层水和东河塘稀油,在45℃条件下,利用旋转液滴法测试了不同分子结构阴离子双子表面活性剂与稀油间的界面张力,并以GA12-4-12为对象,测试了其在不同浓度时的动态界面张力,考察了其与非离子表面活性剂ANT的复配性能。结果表明:连接基长度及碳链长度越长,油水界面张力越低;随GA12-4-12浓度增加,界面张力先降后升,0.3%时油水界面张力仅0.00885mN/m,但时间稳定性变差;GA12-4-12与ANT复配协同效果明显,复配比为4∶1时0.1%(GA12-4-12+ANT)加量可使油水界面张力达超低(0.00884mN/m),明显降低了GA12-4-12用量。可见GA12-4-12与ANT复配体系具有低剂量下提高原油采收率的性能,建议用该配方进行提高原油水驱采收率试验研究工作。     

Experimental investigation the effect of nanoparticles on micellization behavior of a surfactant: Application to EOR

Chemical stimulation such as surfactant flooding in petroleum reservoirs makes efforts to produce remained oil and improve sweep efficiency by means of different phenomena such as lowering interfacial tension and wettability alteration of reservoir rock. Implementing concentration of surfactant through surfactant flooding is one of the big challenges while interfacial tension between surfactant solution and oil after certain concentration involves little changes such as critical micelle concentration (CMC). This article highlights the effect of nanosilica on CMC of Zyziphus Spina Christi, as sugar-based surfactant, in aqueous solutions for enhanced oil recovery and reservoir stimulation purposes. A conductivity approach was selected to assess the CMC of the introduced surfactant in aqueous solution at 25°C. The influence of nanosilica concentrations on CMC variation of introduced surfactant is considered. It is found that CMC of introduced surfactant decreased while the concentration of the nanosilica increased. Results from this study can aim in optimum condition selection of surfactant flooding as an enhanced oil recovery ends.     

PRODUCING ULTRALOW INTERFACIAL TENSION AT THE OIL/WATER INTERFACE

In view of the world-wide shortage of petroleum and the fact that a large amount of residual oil will remain in the reservoir after the primary recovery and water flooding stages, the use of Enhanced Oil Recovery (EOR) methods to recover as much as possible of this residual oil has become increasingly important worldwide. The predominant and most promising EOR technique is the micellar-polymer flooding process which uses a surface active agent (a surfactant) to decrease interfacial tension and hence allows oil to freely move from its original location through the porous media. The purpose of this paper is to present an experimental study of the factors affecting the equilibrium interfacial tension (IFT) at the oil/water interface. A large number of experiments was conducted to study the variations of IFT as a function of many parameters including reservoir temperature, pressure, surfactant concentration, and salinity. An Arabian heavy crude oil was used in the analysis along with three different synthetic surfactants and two formation waters. The pendent drop technique enhanced by video imaging was employed for measuring IFT. It was found that for the ranges of variables considered in this study, IFT decreases with temperature and salinity, increases with pressure, and decreases exponentially with surfactant concentration.     

Review of surfactant-assisted chemical enhanced oil recovery for carbonate reservoirs: challenges and future perspectives

A significant fraction of the conventional oil reserves globally is in carbonate formations which contain a substantial amount of residual oil. Since primary and secondary recovery methods fail to yield above 20%–40%of original oil in place from these reserves, the need for enhanced oil recovery(EOR) techniques for incremental oil recovery has become imperative. With the challenges presented by the highly heterogeneous carbonate rocks,evaluation of tertiary-stage recovery techniques including chemical EOR(c EOR) has been a high priority for researchers and oil producers. In this review, the latest developments in the surfactant-based c EOR techniques applied in carbonate formations are discussed, contemplating the future direction of existing methodologies. In connection with this, the characteristics of heterogeneous carbonate reservoirs are outlined. Detailed discussion on surfactant-led oil recovery mechanisms and related processes, such as wettability alteration, interfacial tension reduction, microemulsion phase behavior, surfactant adsorption and mitigation, and foams and their applications is presented. Laboratory experiments, as well as field study data obtained using several surfactants, are also included.This extensive discussion on the subject aims to help researchers and professionals in the field to understand the current situation and plan future enterprises accordingly.     

低渗透油藏自发渗吸驱油实验研究

通过低渗透亲水岩心自发渗吸实验,探讨了低渗透油藏不同界面张力体系的渗吸驱油过程。研究结果表明,注入水渗吸体系因毛细管力较高、毛细管力与重力比值较大,其渗吸过程为毛细管力支配下的逆向渗吸。与注入水渗吸结果相比,化学剂溶液因降低油水界面张力,在孔隙介质中能使更多的原油参与渗流过程,使更多的剩余油变为可动油,提高了渗吸平衡时的原油采出程度,因而提高了低渗透油藏原油的采收率。     

PRODUCING ULTRALOW INTERFACIAL TENSION AT THE OIL/WATER INTERFACE

ABSTRACT

In view of the world-wide shortage of petroleum and the fact that a large amount of residual oil will remain in the reservoir after the primary recovery and water flooding stages, the use of Enhanced Oil Recovery (EOR) methods to recover as much as possible of this residual oil has become increasingly important worldwide. The predominant and most promising EOR technique is the micellar-polymer flooding process which uses a surface active agent (a surfactant) to decrease interfacial tension and hence allows oil to freely move from its original location through the porous media. The purpose of this paper is to present an experimental study of the factors affecting the equilibrium interfacial tension (IFT) at the oil/water interface. A large number of experiments was conducted to study the variations of IFT as a function of many parameters including reservoir temperature, pressure, surfactant concentration, and salinity. An Arabian heavy crude oil was used in the analysis along with three different synthetic surfactants and two formation waters. The pendent drop technique enhanced by video imaging was employed for measuring IFT. It was found that for the ranges of variables considered in this study, IFT decreases with temperature and salinity, increases with pressure, and decreases exponentially with surfactant concentration.     

Development of a Method for the Extraction of Oil from Clay by Friendly Phase Transfer Catalyst

Abstract

The separation of waste oil from clay was studied using benzyl triethanol ammonium chloride as phase transfer catalyst. The study showed that the surface tension has an effect on oil recovery. An induced air flotation process was used and polymeric decyl phenol formaldehyde ethoxylate was used as the collector. The effects of various parameters including concentration of catalyst, collector, time of flotation, contact angle, and zeta potential on oil extraction were studied. The results show that oil recovery increases with time of flotation up to a maximum and then levels off. Oil recovery is marginal if the flotation time is extended beyond 12 min. For example, oil recovery increases by only 4% for 25 g oil and 20 g surfactant in the feed when flotation time increases from 12 to 15 min. Oil recovery also increases with surfactant dosage. Furthermore, oil recovery was enhanced by controlling the interfacial tension at the oil–water and water–air interfaces. The mechanism of oil separation was discussed according to micelle composition and the calculated oil recovery obtained was 87%. Furthermore, the kinetic study proved that the process is first order and depends on catalyst concentration. Oil recovery follows a Gibbs adsorption equation. The molecular interaction parameter at the aqueous solution–air interface was also calculated. The results proved that the extraction of oil from solid phase can be conducted by adding phase transfer catalyst. Moreover, the article suggests a model of oil separation from soil according to specifications of adsorbed oil, including isoparaffin and n-paraffin that were analyzed by gas chromatography technique.     

Wettability Modification of Fractured Carbonates Using Sodium Metaborate Part II: History Match Results and Sensitivity Simulations

Abstract

Chemical-based wettability modification has become important for the worldwide abundance of fractured carbonates with the potential to enhance water imbibition to expel more oil from a matrix to the fractures. A systematic experimental and modeling approach on the combined benefit of wettability alteration for enhanced water imbibition and interfacial tension reduction is presented. Brine, alkali, and alkali–surfactant solutions are injected sequentially to improve oil recovery from a fractured mixed-wet carbonate core. The experiment was successfully modeled with a 3D chemical flooding reservoir simulator with wettability alteration capability. Part I discussed the laboratory results and presented the modeling approach and the waterflood history match results. The history match procedure and results for wettability modification using an alkali agent and interfacial tension (IFT) reduction with surfactant are discussed in this article. Sensitivity simulations to some key parameters are also presented.