无碱表面活性剂-聚合物复合驱技术研究进展

无碱表面活性剂-聚合物二元复合驱可避免碱引起的结垢、乳化、腐蚀等负面作用,降低投资和操作成本,是具有应用前景的化学驱提高石油采收率新技术。目前存在主要问题有:缺少高效稳定的活性剂工业化产品,驱油机理及主要影响因素理论研究薄弱,评价方法不健全,矿场试验少、技术风险较大。影响表面活性剂-聚合物二元复合驱驱油效率的主要因素有体系黏度、界面张力、乳化强度等,二元体系具有较高的黏度是提高采收率的重要保障,体系油水界面张力越低驱油效率越高,体系乳化性能也显著影响驱油效果。表面活性剂-聚合物二元复合驱矿场试验取得了一定效果,但也暴露出一些问题,需要提高配方适应性、驱油剂产品质量稳定性,优化注入方案,加强现场监测和跟踪调整等。     

The Application of Nanofluids for Enhanced Oil Recovery: Effects on Interfacial Tension and Coreflooding Process

Most oil reservoirs around the world are experiencing their second half of life. Hence, the necessity of appropriate enhanced oil recovery (EOR) method as a more efficient technology gets further importance. Nanotechnology is an advanced technology that has proved its potential to enhance oil recovery. In this study, some selected types of nanoparticles were used, which were aluminum oxide, iron oxide, and silicon oxide treated by silane, as EOR agents during different flooding scenarios and EOR experiments under surface conditions. For the first time, the application of propanol as a dispersing agent of nanoparticles and EOR agent in the formation was investigated by this research work. In order to examine the recovery mechanisms of nanofluids, interfacial tension (IFT), and contact angle measurements between different concentrations of nanofluids and crude oil were measured. Then, several coreflood experiments were conducted to investigate their impacts directly on recoveries. The experiment results show that the nanofluids can decrease the IFT between water and oil phases and make the solid surface more neutral wet. Results indicate that aluminum oxide and silicon oxide treated by silane are good agents for enhanced oil recovery, while silicon one changes rock wettability more in addition to reduction of interfacial tension between oil and water. According to the results the future expectation is that these nanoparticles with their dispersing agent could mobilize more oil in the pore network at field scale to improve oil recovery.     

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.     

特高含水后期提高采收率物理模拟实验

为了探索特高含水后期剩余油的潜力区和不同驱油方法提高采收率的机理,采用三维大模型物理模拟实验,研究了高倍数水驱、活性剂驱、聚合物驱、二元复合驱、微球-乳化剂驱过程中注入压力、波及系数的变化情况和剩余油饱和度的分布特征。研究结果表明,特高含水后期提高采收率的潜力区为未波及区的剩余油和已波及的弱水洗区和中水洗区,而不是强水洗区;继续高倍数水驱和超低界面张力活性剂驱不能进一步扩大波及系数,提高采收率潜力小,需采用深部调堵+微调驱油相结合的技术。自聚集微球-乳化剂驱具有封堵-驱替-再封堵-再驱替的特点,可扩大波及系数38.6%,提高采收率19.1%,其封堵能力、波及范围和驱油效率均明显高于聚合物驱和二元复合驱,具有良好的应用前景。     

化学蒸汽驱提高驱油效率机理研究

化学蒸汽驱的目的是解决胜利油区中深层稠油油藏因油层压力高导致蒸汽驱采收率低的技术瓶颈。采用室内物理模拟实验,以数值模拟技术为手段,通过研究高温泡沫剂一高温驱油剂一原油组分的相互作用机制及温度、油水界面张力对驱油效率的影响,对比高温泡沫剂辅助蒸汽驱、高温驱油剂辅助蒸汽驱、高温泡沫剂与高温驱油剂辅助蒸汽驱提高采收率的幅度,揭示了化学剂与蒸汽复合作用提高采收率机理。结果表明,高温驱油剂的油水界面张力达到10^-3mN/m数量级,才能取得较好的驱油效果,可提高驱油效率5.1%;高温泡沫剂的临界含油饱和度为0.25～0.3,可提高驱油效率8.1%;与蒸汽驱相比,化学蒸汽驱可发挥高温驱油剂和泡沫剂的协同作用,提高驱油效率14.6%,具有明显的技术优势。     

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.     

Dynamic Interfacial Tension Between Crude Oil and Novel Surfactant Flooding Systems Without Alkali

The surface tensions of tetradecylmethylnaphthalene sulfonate (TMNS) surfactant aqueous solution and the dynamic interfacial tension (DIT) between crude oil, from Shandong Shengli oil field of China, and the surfactant solution without alkaline, was measured. Results indicate that the TMNS surfactant had great capability and efficiency of lowering the solution surface tension. The critical micelle concentration (cmc) is 0.001 mass% and the surface tension at this concentration is 28.19 mN.m^-1. It was also found that the TMNS surfactant is greatly effective in reducing the interfacial tensions and can lower the tension of crude oil-water interface to ultra-low at very low concentration, 0.002 mass%, without alkali and other additives. Both chromatogram separation of flooding and breakage of stratum are avoided effectively. The lower salinity is favorable for the flooding systems, lowering the DIT. The synthesized TMNS surfactant flooding systems without alkali and sodium chloride, decreasing the cost of oil recovery and avoiding the stratum being destroyed, would have a great prospect for enhanced oil recovery (EOR).     

分子沉积膜驱油技术研究现状

综合分析了水溶性分子沉积膜的表面及界面特性、吸附特性、表面zeta电位、破乳作用和驱油机理。在此基础上，结合国内外资料认为应用分子沉积膜驱油荆不降低水溶液的表面张力，能够降低油水界面张力但降低幅度不大，能够降低油水界面粘度，有自组织破乳作用，能自发吸附在呈负电性的岩石表面上并放热，能通过改变岩石表面润湿性来剥离残余油提高采收率。指出了分子沉积膜驱油荆在三次采油中的主要应用领域，提出了分子沉积膜驱油技术在聚合物驱油后进一步提高采收率的方向。     

聚合物驱后石油磺酸盐体系提高采收率室内实验研究

针对孤岛油田中一区Ng4砂层组油藏条件,开展了聚合物驱后以石油磺酸盐为主剂的表面活性剂驱油提高采收率的室内实验研究工作。通过大量的室内实验,研制出以石油磺酸盐为主剂的复配体系,并开展了驱油效率实验。对比了几种低界面张力活性剂驱油体系的驱油效果,筛选出效果最好曲石油磺酸盐驱油配方体系：0．3％SLPS-01C＋0．1％助剂1#。研究了不同转注时机对石油磺酸盐体系提高采收率效果的影响,在注聚合物后含水率最低时,由于聚合物驱的作用,形成“油墙”,可防止表面活性剂窜流,此时转注石油磺酸盐体系效果最好,洗油效果最佳。图4表7参21     

Recent advances in application of nanotechnology in chemical enhanced oil recovery: Effects of nanoparticles on wettability alteration,interfacial tension reduction,and flooding

Chemical methods of enhanced oil recovery (CEOR) are applied for improving oil recovery from different kinds of oil reservoirs due to their ability for modifying some crucial parameters in porous media, such as mobility ratio (M), wettability, spreading behavior of chemical solutions on rock surface and the interfacial tension (IFT) between water and oil. Few decades ago, the surfactant and polymer flooding were the most common CEOR methods have been applied for producing the remained hydrocarbon after primary and secondary recovery techniques. Recently, more attention has been focused on the potential applications of the nanotechnology in enhanced oil recovery (EOR). For this purpose, many studies reported that nanoparticles (NPs) have promising roles in CEOR processes due to their ability in changing oil recovery mechanisms and unlocking the trapped oil in the reservoir pore system. This paper presents a comprehensive and up-to-date review of the latest studies about various applications of nanoparticles (NPs) within the surfactant (S), polymer (P), surfactant-polymer (SP), alkaline-surfactant-polymer (ASP) and low salinity waterflooding processes, which exhibits the way for researchers who are interested in investigating this technology. The review covers the effects of nanoparticles on wettability alteration, interfacial tension reduction and oil recovery improvement, and discusses the factors affecting the rock/fluid interaction behavior in porous media through the nanofluid flooding.     

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。     

Evaluation of Interfacial Tension Between Zahra Oil and ASP Solution

Alkaline-surfactant-polymer (ASP) flooding has been proved to be an effective enhanced oil recovery (EOR) method. Reduction of interfacial tension (IFT) between crude oil and ASP solution is the main mechanism in ASP flooding. Evaluating IFT between crude oil and ASP solution is a key parameter for ASP flooding in laboratory experiments or field projects. In order to obtain good result of ASP flooding in the reservoir in Zahra field, the influence of the concentration of Na₂CO₃ on IFT between Zahra crude oil and ASP solution with three different surfactants, BHJC, SS-231, and SS-233, was researched. IFT was measured with surface tension meter SVT20N, Dataphysics Co. Germany, at 72°C. For the view of IFT result anionic surfactant BHJC is more suitable for the Zahra oil field. This research is helpful for practical application of ASP flooding in Zahra oil field.     

Dynamic Interfacial Tension Between Crude Oil and Novel Surfactant Flooding Systems Without Alkali

Abstract

The surface tensions of tetradecylmethylnaphthalene sulfonate (TMNS) surfactant aqueous solution and the dynamic interfacial tension (DIT) between crude oil, from Shandong Shengli oil field of China, and the surfactant solution without alkaline, was measured. Results indicate that the TMNS surfactant had great capability and efficiency of lowering the solution surface tension. The critical micelle concentration (cmc) is 0.001 mass% and the surface tension at this concentration is 28.19 mN.m^?1. It was also found that the TMNS surfactant is greatly effective in reducing the interfacial tensions and can lower the tension of crude oil-water interface to ultra-low at very low concentration, 0.002 mass%, without alkali and other additives. Both chromatogram separation of flooding and breakage of stratum are avoided effectively. The lower salinity is favorable for the flooding systems, lowering the DIT. The synthesized TMNS surfactant flooding systems without alkali and sodium chloride, decreasing the cost of oil recovery and avoiding the stratum being destroyed, would have a great prospect for enhanced oil recovery (EOR).     

稠油降黏剂驱提高采收率机理

为系统研究降黏剂驱这一新的开发方式提高采收率机理,应用单管填砂驱油模型、三维填砂驱油模型和微观玻璃刻蚀驱油模型,测试降黏剂驱的驱油效率和波及系数,并对其原因进行分析。实验结果表明,降黏剂驱通过提高驱油效率和增加波及系数提高采收率。与水驱相比,降黏剂驱可提高驱油效率13%,其机理为:①分散乳化,形成水包油的小油滴,有利于通过狭窄的喉道,降低原油的表观黏度;②降低界面张力,增加毛管数,降低残余油饱和度。同时,降黏剂驱将波及系数由水驱时18.8%提高到39.9%,其机理为:①乳液调驱,分散乳化的原油进入水窜通道,水渗流面积减小、阻力增加,后续注入液进入以前未波及区域;②贾敏效应,降黏乳化小油滴聚并成大油滴堵在孔喉处,周围驱替液转向。研究明晰了降黏剂驱提高采收率机理,为后续开发技术界限研究及现场应用奠定基础。     

Application of Grid partitioning based Fuzzy inference system method as a novel approach for prediction of interfacial tension of hydrocarbon and carbon dioxide

Nowadays the importance of enhanced oil recovery (EOR) processes increases because of increasing demand of energy and declination of oil reservoirs. Due to this fact the researchers attracted to study performance of EOR methods. one of the high efficient methods is carbon dioxide injection which is favorable because of low cost and environmental friendly viewpoints. One of important parameters which have straight effect on recovery of injection is interfacial tension between carbon dioxide and hydrocarbons. In the present investigation the main objective is proposing the Grid partitioning based Fuzzy inference system method as novel approach to predict interfacial tension of carbon dioxide and hydrocarbon in terms of temperature, pressure, liquid and gas densities and molecular weight of alkane. The coefficients of determination for different datasets of training and testing of estimating algorithm are determined as 0.9919 and 0.9899. This results express the algorithm has potential of estimating interfacial tension of hydrocarbons and carbon dioxide.     

二元无碱驱油体系的室内研究与评价

随着三元复合驱技术研究的不断深入, 三元复合驱体系中碱对石油开采过程及地层造成的危害日益凸现。以自制石油磺酸盐NPS-2为表面活性剂, 通过考察不同质量分数的NaCl和石油磺酸盐对大庆采油四厂油水界面张力的影响, 确定了二元无碱驱油体系配方, 并对该体系的应用广泛性和驱油效果进行了评价。结果表明, 从自制石油磺酸盐为表面活性剂, 二元无碱驱油体系合适配方为C_NaCl=0.6%~1.2%, C_NPS-2=0.1%~0.3%, C_HPAM=0.12%. 该二元复合驱配方体系可使油水界面张力降至超低, 全部达到10^-3mN/m 数量级, 最低可达10^-4mN/m 数量级, 能够避免由碱引起的对地层和采油设备的损害, 具有很高的现场应用价值。     

套保油田降粘剂驱油室内实验研究

本文针对套保油田储层胶结松、易出砂，且隔层薄的特点，选用了三种降粘剂进行室内驱油实验研究，并考察了三种降粘剂的驱油效果。结果表明，选用A型降粘剂、浓度为0.5％、注入速度为1.0mL/min，具有良好的驱油效果。     

The Effect of Alkali and Surfactant on Polymer Molecular Structure

Abstract

With the technical development of enhanced oil recovery (EOR), the alkali/surfactant/polymer (ASP) compound flooding technique has been the necessary choice in Daqing oilfield. Compared to average polymer flooding, ASP compound solution decreases the interfacial tension (IFT) between water and crude oil; however, the viscosity and viscoelasticity of ASP solution were performed by surfactant and alkali, both of which could affect the polymer moleculal structure and the oil recovery of ASP flooding. Considering practical requirements in oilfield development, much effort has been focused on the effect of alkali and surfactants on polymer solution by laboratory experiment and theoretical analysis. The results indicate that alkali and surfactants cause the interfacial tension decrease; at the same time, the molecular structure of the polymer is changed and the viscosity and viscoelasticity of polymer solutions are decreased. In addition, alkali neutralizes with negative ion on polymer molecular and causes the polymer molecular chains to curl up, forming a “band” molecular structure. Those actions could make viscoelastic behavior and rheological property of ASP solution weak.     

STUDYING THE INTERACTIONS BETWEEN AN ARABIAN HEAVY CRUDE OIL AND ALKALINE SOLUTIONS

An experimental study to examine the effectiveness of alkaline flooding for the recovery of an Arabian heavy crude oil is presented. The interfacial tension (IFT) behavior of crude oil/alkali systems over a wide range of parameters (pressure, temperature, alkali concentration and time) was studied. These alkaline reagents react with the acidic species in crude oil to form surface-active soaps in-situ. This leads to a lowering of interfacial tension (IFT) and subsequently the mobilization of residual oil. The equilibrium IFTs obtained through alkaline flooding are compared with the IFTs when a synthetic surfactant (dodecyl benzene sulfonic acid sodium salt) is used in EOR recovery. A mathematical model representing the complete chemistry of the transient process is also presented. The model consists of a set of differential equations describing reactions, diffusion, and adsorption at the oil/alkaline solution interface. The kinetic parameters in the model are obtained through a differential algebraic optimization technique. The concentration of the surface active species are related to the measured IFTs through an independent step that is based on isolating the surface active species formed by the reaction between the acids in the crude oil and the alkaline solution. A sensitivity analysis using the model is carried out to study the effect of surface potential and alkaline concentration on the transient interfacial tensions.     

A Performance Evaluation of Glycolipid Biosurfactant Synthesized by the Enzyme-catalyzed Method

The practice of enhanced oil recovery (EOR) technique shows that the study and application of biosurfactant flooding system have a vast potential for future development. The authors challenge the traditional idea that the oil displacement surfactant must have ultra low interfacial tension. By changing the wettability of reservoir rock as main target, the glycolipid biosurfactant compounded system was developed by enzyme-catalyzed method in laboratory, and a series of experiments had been done combining with reservoir physical measurement. The properties of the active system were characterized by interfacial characters, disbonded, seepage characteristics, antibiotic property, and oil displacement efficiency.