无碱二元体系的黏弹性和界面张力对水驱残余油的作用

三元复合驱含碱驱油体系会大幅度降低聚合物溶液的黏弹性,引起地层粘土分散和运移、形成碱垢及导致地层渗透率下降。为此提出利用不加碱可形成超低界面张力的聚合物/甜菜碱表面活性剂二元复合体系驱油。通过流变性实验及微观模型驱油实验,分析了表面活性剂对聚合物表面活性剂二元复合体系黏弹性的影响和聚合物表面活性剂二元复合体系的黏弹性及界面张力对采收率的影响。对聚合物表面活性剂二元复合体系提高水驱后残余油采收率机理的研究表明:在驱替水驱后残余油过程中,聚合物表面活性剂二元复合体系利用了聚合物溶液的黏弹特性和表面活性剂的超低张力界面特性,水驱后残余油以油丝和乳状液形式被携带和运移,随着二元驱油体系的黏弹性的增加和界面张力的降低,水驱后二元驱后的采收率增加,降低界面张力的驱油效果(指达到超低)比提高体系的黏弹性的效果更明显。     

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。     

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.     

基于低质量浓度表面活性剂的复合驱效果评价

以往为了达到超低界面张力,复合驱大多使用较高质量浓度的表面活性剂,通常为1 000~3 000 mg/L,不仅增加了成本且未必能取得好的驱油效果。为了探究低质量浓度表面活性剂的驱油效果,设计了低质量浓度表面活性剂的复合驱物理模拟实验。静态实验结果表明,在低质量浓度表面活性剂条件下,油水界面张力可达到10-2mN/m数量级及以下,加碱后,界面张力更低;碱和表面活性剂都会对聚合物的粘度和粘弹性产生影响,碱在较高温度下会大幅度降低复合体系的粘度和粘弹性。驱油实验结果表明,与水驱相比,在所选择的低质量浓度表面活性剂驱油体系中,表面活性剂—聚合物二元复合驱和碱—表面活性剂—聚合物三元复合驱均可提高采收率19.5%以上,三元复合驱的驱油效果最好,提高采收率21.8%以上。这表明低质量浓度表面活性剂驱油体系驱油效果很好。     

聚合物/两性表面活性剂二元体系提高水驱后残余油采收率研究

针对三元复合驱中的碱大幅度降低聚合物溶液的黏弹性，降低波及效率和驱油效率，含碱驱油体系引起地层黏土分散和运移、形成碱垢、导致地层渗透率下降等问题，利用不加碱可形成超低界面张力的聚丙烯酰胺／两性表面活性剂二元复合体系，通过人造岩心驱油实验，研究了聚表二元复合体系提高水驱后残余油采收率的可能性。研究表明，聚表二元复合体系在驱替水驱后残余油中，可以同时发挥活性剂的超低界面张力特性和聚合物溶液的粘弹特性，使得该二元体系的采收率高于单一的表面活性剂体系和聚合物驱油体系，并且二元体系的聚合物浓度越高，采收率越高。     

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).     

表面活性剂/聚合物二元复合体系驱油效果研究

针对大庆油田应用的新型表面活性剂/聚合物二元复合体系,开展了微观仿真模型驱油实验和岩心驱油实验研究;对比了水驱油后聚合物溶液驱油、表面活性剂溶液驱、无碱表面活性剂/聚合物（SP）二元复合驱体系驱油3种方案的驱油效果,研究了SP二元复合体系界面张力和乳状液的含水率对其驱油效果的影响规律。研究表明:SP二元体系的驱油效果明显好于聚合物溶液和表面活性剂溶液的一元体系,人造岩心水驱油后,开展SP二元复合体系驱油提高采收率17.50%;人造岩心水驱后聚驱,再开展SP二元复合体系驱油提高采收率10.10%。该研究对指导SP二元复合体注入方案设计具有重要意义。     

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).     

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.     

聚驱后缔合聚合物三元复合驱提高采收率技术

三元复合驱是大庆油田聚驱后进一步提高采收率的重要途径,其驱油体系须保证超低油-水界面张力,且能大幅提高波及能力。通过研究烷基苯磺酸盐（ABS）-缔合聚合物（HAPAM）-NaOH三元复合驱体系的性能,并与超高分子量部分水解聚丙烯酰胺（HPAM）三元复合体系进行对比。研究结果表明,HAPAM三元复合体系在NaOH浓度为0.5%~1.2%、ABS浓度为0.025%~0.300%时具有良好的界面活性,油-水界面张力可达10^-3mN/m数量级。0.16%HAPAM-0.3%ABS-1.2%NaOH三元复合体系黏度达108.8 mPa ·s,采用HPAM达到相同黏度其浓度为0.265%,因此HAPAM可降低聚合物用量40%。驱油实验结果表明,在相同黏度下,HAPAM三元复合体系在不同孔隙介质中均能提高聚驱后采收率13%以上,比HPAM三元复合体系多提高采收率6%以上。HAPAM三元复合体系具有更高的阻力系数与残余阻力系数、更好的黏弹性以及乳化稳定性,可以为大庆油田聚驱后提高采收率提供新的技术手段。     

The Effects of Oil Displacement Efficiency and Conformance Efficiency on Viscosity of ASP Flooding in a Heterogeneous Reservoir

According to the formation conditions of alkali/surfactant/polymer (ASP) flooding in Daqing oilfield, the effects of the concentrations for polymer and alkali in ASP solution on oil recovery efficiency were studied by means of oil displacement experiments and numerical simulation. The effects on improving oil recovery by different ASP solution have been investigated from the aspects of interfacial characteristics and rheological behavior. Only the apparent viscosity of ASP solution reaches the critical viscosity, the ultralow interfacial tension can play an important role in enhanced oil recovery. Both displacement experiments and numerical simulation shows that ASP solution has a critical viscosity to certain heterogeneity.     

Design of Alkaline/Surfactant/Polymer (ASP) Slug and its use in Enhanced Oil Recovery

Abstract

Studies have been done to design an optimum composition of alkali/surfactant/polymer (ASP) slug and its application in flooding to increase the additional recovery of oil. A very low concentration of alkali and surfactant is used to achieve ultra-low interfacial tension between the trapped oil and the injection water, and polymer is used to increase the viscosity of the injection water for mobility control. Based on the experimental results of physico-chemical properties of polymer, surfactant, and alkali and their mutual interaction in solution, an ASP slug of composition SDS: 0.1 wt%, SDBS: 0.075 wt%, polyacrylamide: 2,000 ppm, and NaOH: 0.7 wt% has been recommended for flooding. Two sets of core-flooding experiments have been conducted using the designed ASP slug in a tri-axial core holder to measure the additional recovery of oil. The average additional oil recovery over conventional water flooding was found to be more than 20% of the original oil in place (OOIP).     

复合驱中界面张力数量级与提高采收率的关系研究

文章分析了表面活性剂/聚合物二元复合驱和碱/表面活性剂/聚合物三元复合驱驱油指标(超低界面张力必须达到10-3mN/m)理论的缺陷;在大量岩心试验的基础上,比较了不同界面张力下的采收率值,认为平衡界面张力为10-3mN/m不是表面活性剂驱油及复合驱的必要条件,平衡界面张力为10-2mN/m时也能达到与前者同样的驱油效果;并且只要瞬时界面张力达到10-3mN/m,也能达到较好的驱油效果,从而为表面活性剂复合驱的广泛应用提供了实验基础。     

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.     

非均质油藏复合驱合理界面张力实验研究

针对油田三元复合驱油实际需求,通过调整活性剂、聚合物和碱的类型和配方组成,在两种具有大庆油田油藏典型地质特征的物理模型上对低活性剂浓度三元复合体系的适应性进行了实验评价。结果表明,非均质油藏三元复合驱应当兼顾扩大波及体积和提高洗油效率。将复合体系中表面活性剂和碱的浓度分别降低到0.1%和0.8%,驱替相与被驱替相间界面张力保持为0.01mN/m,并适当增大聚合物相对分子质量或增加聚合物浓度,低活性剂浓度三元复合体系驱原油的采收率可以增加20%以上。     

模拟二元复合驱采出液稳定性影响因素研究

二元复合驱是中高渗透油藏提高采收率的主要技术之一。为了研究聚表二元驱对乳状液稳定性的影响,选取含聚表水与模拟油组成油水界面体系,测试了油水界面张力、界面剪切黏度等参数,并结合乳状液静置脱水效果,分析聚表二元驱对油水采出液稳定性的作用机理。采用含聚合物和表面活性剂的水相与模拟油配制成模拟油采出液,用于测试不同聚合物及表面活性剂浓度对界面张力的影响。界面张力结果表明:聚表二元驱成分能够显著增大油水乳状液的稳定性,但聚合物与表面活性剂在界面活性上存在明显差异;界面剪切黏度的影响因素主要为聚合物;静置脱水实验表明,影响油水乳状液稳定性的主要因素为表面活性剂。这与过去的观点存在矛盾,即认为界面剪切黏度是影响乳状液稳定性的关键。因此本研究认为存在其他因素影响乳状液稳定性。     

三元复合驱的驱油特征研究

大量室内研究和矿场试验结果表明,在高效的表活剂条件下,三元复合驱是一种非常有效的三次采 油方法,具有良好的应用前景。文中应用数值模拟技术并结合室内研究,给出了三元复合体系不同界面张 力和粘度比条件下,在非均质油层中的驱油特征。分析结果表明,三元复合驱与聚合物驱相比,对油层非 均质性有更大的适用范围;对于非均质油层的三元复合驱,采用增加体系的粘度和降低体系的界面张力的 方式都能获得较好的提高采收率效果,但高粘度是获得好的提高采收率的关键;采取分层注入的方式,或 者在三元复合驱后对高渗透层进行封堵,能更有效地采出中、低渗透层的剩余油,进一步提高采收率。本 项研究对认识三元复合驱的驱油机理和编制调整矿场试验方案提供了重要依据。     

利用磷硅酸盐-表面活性剂-聚合物复合体系提高原油采收率

"表面活性剂-碱-聚合物"三元复合体系是提高采收率的实用技术之一,但其中强碱NaOH会引起采油设备腐蚀和地层结垢问题,这影响了该技术的大规模推广应用。SJT-B助剂是一种磷硅酸盐化学助剂,用助剂代替碱进行了三元复合体系驱油实验。对表面活性剂-SJT-B助剂-聚合物三元复合体系的缓蚀防垢作用、界面张力、吸附、色谱分离、流动特性和驱油效果进行的研究结果表明,表面活性剂-SJT-B助剂-聚合物三元复合体系具有缓蚀防垢、降低界面张力的效果,且其动静吸附量低。以大庆杏树岗油田的地质特征为基础建立的物理模型上进行了驱油实验,结果证实,表面活性剂-SJT-B助剂-聚合物三元复合体系的调驱效果好于现有表面活性剂-碱-聚合物三元复合体系。     

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.     

低碱三元复合驱油实验研究

针对三元复合驱体系在表面活性剂浓度一定的情况下，碱和聚合物浓度变化对体系粘度、界面张力有一定的影响，根据驱油效率实验，优选出三元复合驱体系中碱的最佳浓度范围。结果表明，就该实验所采用的三元复合体系。在考虑超低界面张力的同时，必须考虑体系的粘度，其超低界面张力并不是提高原油采收率的必要条件。