Characterization of ternary compound viscosity reducer system on viscosity of viscous crude oil

Based on the theory that viscous crude oil can form stable two-phase oil-water interfacial molecular membrane with surfactant, the oil-water interfacial activity and viscosity reduction of oil-water interface of viscous crude oil were studied for the ternary compound system, including anionic surfactant alpha olefin sulfonate (AOS), weak alkali Na₂CO₃ and four different kinds of nonionic surfactant emulsifying silicon oil (LKR-1023), lauryl diethanolamide (LDEA), isomeric alcohol ethoxylates (E-1306), and polyoxyethylene sorbitan monooleate (T-80). Results showed when lipophilic or hydrophilic nonionic surfactants were used separately in the same compound system. The viscosity of viscous crude oil could be reduced, but the viscosity reduction efficacy was not desirable. However, using LKR-1023, E-1306, and T-80 as nonionic surfactant with mass fraction 1.0%, the viscosity reduction rate of viscous crude oil reaches 98.92%, 98.29%, and 96.87%, respectively. With 1.4% of LDEA, the viscosity reduction rate of viscous crude oil can reach 98.89%. Through all different kinds of the nonionic surfactant tested, oil-in-water (O/W) emulsion under LDEA ternary compound system has been proved to be the most stable with no phase inversion. Therefore, it is promising to improve the viscosity reduction of the super viscous crude oil by selecting the proper surfactant and dosage.     

Stability of oil-in-water emulsions by SDS compound

Abstract

Surfactants are often required to reduce emulsion viscosity and heavy-oil flow resistance in pipelines, thereby forming a stable oil-in-water emulsion under shear stress. This study aimed to quantitatively discuss and analyze the stability of oil-in-water emulsions and characterize them through the initial viscosity change rate K. The value of K was obtained based on the oil-rich-phase viscosity curves of oil-in-water emulsions comprising sodium dodecyl sulfate (SDS), heavy oil, and water at different time points. Results showed that a smaller K corresponded to a more stable emulsion according to analysis of the effect of the compound system on emulsion stability and the synergistic mechanism. We then combined with 1-pentanol and octyldecyl glucoside (APG0810) with SDS. Results showed that the K values of the emulsions decreased from 19.457 to 6.284, and 19.457 to 5.834, respectively, after mixing 6% 1-pentanol and 0.4% APG, respectively, with 0.14% SDS. Then, 0.14% SDS was compared with 1.2% a mass fraction of each of the three additives to form a compound system, and the K values were found to follow the trend K_{1-pentanol/SDS} > K_APG/SDS. Thus, the stability of APG/SDS oil-in-water emulsion was better than that of 1-pentanol/SDS emulsion.     

Effect of organic alkali,n-alkanol,and nonionic surfactant ternary compound system on viscosity reduction of viscous crude oil

To reduce the viscosity of viscous crude oil and flow resistance, the effect of a ternary compound system including organic alkali, n-alkanol, and nonionic surfactants on viscous crude oil viscosity reduction was studied. The results showed that n-alkanol effectively reduced the droplet size of an emulsion and the viscosity of viscous crude oil and improved the fluidity of viscous crude oil. Of the low-carbon n-alkanols, n-pentanol has the best viscosity-reducing effect. The organic alkali avoids the phenomenon of fouling and corrosion caused by inorganic alkali and reacts with the acidic macromolecular components in viscous crude oil to generate alkanolamides, which produce synergistic effects with nonionic surfactants and reduce the interfacial tension between oil and water. In the ternary compound of organic alkali, n-alkanol, and nonionic surfactant, the viscosity reduction effect of viscous crude oil is significantly enhanced compared with that of a single reagent. The viscosity reduction rate of viscous crude oil of the diethanolamine ternary compound system reached 98.1% and was the best choice by experimental validation. It is shown that a reasonable formula of compound system and dosage can significantly reduce the viscosity of viscous crude oil.     

Effects of the compound system of alkali and alkyl glycosides on the stability of oil-in-water emulsions

Abstract

The effects of Na₂CO₃, nonionic surfactant octyldecyl glucoside (APG0810), and inorganic salt addition on the water separation ratio and apparent viscosity of oil-in-water (O/W) emulsions were investigated. The influences of this compound system on the stability of the emulsion and its synergistic mechanism were also analyzed. Results revealed that in the first compound situation, when APG was selected as the main surfactant and had a concentration of 0.1%, the mass concentration of Na₂CO₃ was 0.4%, the emulsion exhibited the strongest stability, and the water separation ratio at 30?°C for 120?min was 20.3%. In the second compound situation, when Na₂CO₃ was used as the main surfactant and had a concentration of 0.1%, the mass concentration of APG was 0.4%, the emulsion displayed the strongest stability, and the water separation ratio at 30?°C for 120?min was 57.8%. The stability of the O/W emulsion increased with increased NaCl addition, and a higher salt concentration corresponded to a lower water separation ratio. After CaCl₂ addition, the apparent viscosity of the emulsion increased sharply, and the O/W emulsion underwent phase inversion to become an water-in-oil (W/O) emulsion. Within the set mass concentration range, increased salt concentration caused the apparent viscosity of the W/O emulsion measured at 50?°C and 30?rpm to decrease gradually but still exceeded 1500?mPa·s.     

Investigation of non-Newtonian flow characterization and rheology of heavy crude oil

The heavy crude oil exhibits a non-Newtonian shear thinning behavior over the examined shear rate. The viscosity of the heavy crude oil decreases about 15.6% when the temperature increased from 30 to 60°C. Heavy crude oil was blended with the aqueous solution of surfactant and saline water in different volumetric proportions of NaCl, and Na₂CO₃ solution mixtures. The addition of 50% of the mixture to the heavy crude oil causes a strong reduction in the viscosity, about 67.5% at 60°C. The heavy crude oil fits the Power law model since it has the lowest average absolute percent error of 0.0291. The flow behavior index of the heavy crude oil reaches a value of 0.9305 at a temperature of 30°C and it increases to 0.9373 when the temperature raises 60°C, while the consistence coefficient decreases from 2.8811 to 2.3558.     

稠油降粘剂复配及降粘效果研究

研究了温度、单一降粘剂和复配降粘剂体系对河南某油田稠油的降粘效果,结果表明,稠油粘度随着温度上升而下降,当温度高于60℃时,粘度随温度升高下降缓慢并逐渐趋于稳定。等量等温试验条件下选取的5种降粘剂中AES的降粘效果最好,确定的降粘剂复配体系最佳复配条件为：AES用量0．2％,温度80℃,OP-10用量0．2％,十二烷基磺酸钠用量0．4％,此时降粘率达到97．50％以上。     

Mechanism of viscosity reduction in viscous crude oil with polyoxyethylene surfactant compound system

Surfactant can be used to form stable oil-in-water emulsion and reduce the viscosity of viscous crude oil. The mechanism of viscosity reduction was studied for nonionic surfactant alkylphenol polyoxyethylene (9) ether (APE-9) compound systems. The results showed that the viscosity reduction of viscous crude oil by water-insoluble alkylphenol polyoxyethylene (4) ether (APE-4) was higher than sodium dodecyl sulfate (SDS, anionic surfactant) and dodecyl dimethyl betaine (BS-12, amphoteric surfactant) in the binary compound system. The viscosity further decreased by ethanolamine. The interfacial tension (IFT) study showed that when the reduction in IFT was the highest, the viscosity reduction was the highest.     

利用HLB值法筛选稠油乳化降黏体系

在油水比为7∶3的情况下,利用HLB值法确定出了大庆稠油乳化的最佳HLB值为8.82,并根据此法确定出了表面活性剂AOS的HLB值为15。对于大庆稠油,根据其形成乳状液的最佳HLB值及不同表面活性剂的HLB值,通过计算得到了该稠油的乳化降黏体系配方为m(AEO3)∶m(AES)=11.5∶1。在油水质量比为7∶3,降黏剂用量0.7%条件下,对大庆稠油的降黏率达77.8%,90min沉降脱水率大于83.3%。     

吉林扶余油田稠油乳化降黏实验研究

针对典型油样进行组分分析,找出原油中影响黏度的主要因素。采用A型水溶性降黏剂进行乳化降黏实验,通过静态评价试验,研究了水溶性A型降黏剂与原油之间形成乳状液的稳定性和粒径分布、油水界面张力、降黏率及洗油率,考察了该降黏剂降黏效果。实验结果表明:原油中蜡含量迭14.7%,高含蜡是影响原油黏度的主要因素;降黏剂浓度越大,乳状液分水率越低,乳状液粒径分布越集中,油水界面张力越低,乳状液越稳定;油水比越大,分水率随降黏剂浓度变化越显著;随降黏剂浓度增大和油水比降低,降黏率逐渐升高,降黏率最高可达91.5%;该降黏剂有较好的洗油效果,洗油率为61.1%。     

国外CO2驱流度控制进一步扩大波及体积方法

CO₂驱油是一种有效的提高采收率方法,矿场成功应用已有60多年。理论上微观驱油效率接近100%,但相对原油,CO₂的低黏度低密度与储层的非均质性导致的黏性指进和重力分离两大典型问题大大降低了气体波及系数。本文综述了国外各种流度控制方法,包括气水交替、聚合物直接稠化CO₂、CO₂泡沫驱、气-化学剂联合方法及气体辅助重力泄油,简要介绍了CO₂驱扩大波及体积的其他方法,分析了每种方法的机理及优缺点,力图为我国CO₂驱油进一步扩大波及体积这一难题积累先进做法和经验。     

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.     

羧酸盐在稠油乳化降粘中的作用

从稠油中分离出天然羧酸组分，并用现代分析手段测定了天然羧酸的结构，详细考察了羧酸含量、结构与乳化降粘性能的关系；关在此基础上采用几种合成羧酸盐改善了稠油的乳化降粘性能；最后合成了一种羧酸和磺酸共缩聚型乳化降粘剂。试验结果表明，其抗钙、镁离子的能力可达700mg／L，所形成的稠油乳状液也较稳定。     

CO2 miscible flooding in low permeability sandstone reservoirs and its influence on crude oil properties

Miscible CO₂ injection process has become widely used technique for the enhanced oil recovery in low permeability reservoirs. Core flooding experiments and field test of CO₂ miscible flooding in low permeability sandstone reservoirs and its influence on crude oil properties was studied. The results showed that CO₂ miscible flooding in low permeability sandstone reservoirs can enhance oil recovery both in laboratory study and field test. The permeability of sandstone reservoirs decreased during CO₂ miscible flooding due to the precipitation of asphaltene of crude oil. The precipitation of asphaltene lead to a reduction of asphaltene content and the apparent viscosity of crude oil. A further study on inhibitors and removers for asphaltene deposits from crude oil should be investigated to prevent and remove asphaltene deposits in low permeability sandstone reservoirs.     

大庆西部斜坡稠油地层流动性影响因素实验研究

针对大庆西部斜坡稠油在开采过程中与地层水和注入水乳化生成高黏的油包水型乳状液降低地层流动性的问题,通过流变性实验和岩心流动实验,研究了乳化、温度及地层渗透率对稠油黏度和地层流动性的影响规律,明确了原油在地层中流动困难的原因及改善流动性的技术方向。结果表明：含水乳化和温度是影响其黏度的主要因素,温度由30℃上升至120℃,脱水稠油黏度降低了95.5%;当含水率低于70%时,原油与水形成油包水型乳状液,含水率越大黏度越大,含水率为70%的稠油的黏度是脱水黏度的30倍左右;地层渗透率、温度及含水乳化对原油地层流动性具有显著的影响,地层渗透率越低、温度越低、含水乳化越严重,原油流动性越差,不同温度和含水率下的采油指数相差可达10倍以上。因此,促使含水稠油乳状液转相是油田降黏增产的有效途径。研究成果对同类油藏开发具有重要的指导意义。      

A Comprehensive Evaluation of High Viscous Crude Oil from Shuguang No. 1 Zone of Liaohe Oil Field

Abstract

The high viscous crude oil from Shuguang No. 1 zone of Liaohe oil field has the characteristics of high density (ρ ₂₀ = 0.9977 g cm^?3), great viscosity (ν ₁₀₀ = 1223.9 mm² s^?1) and high pour point (48°C), which are similar to those of the residue distillation of general crude oils. It contains no gasoline distillation and the diesel oil fraction yield is just 7.19%. It is often used as fuels after emulsification. But this oil is so vicious that it cannot be atomized uniformly and burned fully. In order to make full use of it, this kind of high viscous crude oil has been evaluated comprehensively and the properties of its various distillations are analyzed respectively. The results indicate that this crude oil contains less wax, but more resins and asphaltene, which belongs to low-sulfur naphthene-base crude oils and it is the suitable material to produce high-quality paving asphalt. Based on its characteristics, the optimum processing scheme is put forward and the high-quality paving asphalt is produced by using the distillation higher than 350°C.     

应用降粘剂提高大港稠油油藏水驱采收率

在对大港官109-1断块稠油组成及结构进行分析的基础上,针对油藏高温、高矿化度及水驱采出程度低的特点,研制出一种降粘剂。在含水量大于30%及降粘剂加入量大于1 000 mg/L（占油水总质量）的条件下,能使油水体系形成稳定的O/W乳液,降粘率大于97%,且降粘剂的存在对采出液的破乳脱水没有负面影响。岩心驱油实验结果表明,降粘剂驱油体系比水驱体系稠油采收率提高22%以上,说明使用降粘剂可降低油藏稠油粘度,改善水/油流度比,提高波及系数,明显改善水驱效果。     

STABILITY AND RHEOLOGY OF HEAVY CRUDE OIL-IN-WATER EMULSION STABILIZED BY AN ANIONIC- NONIONIC SURFACTANT MIXTURE

ABSTRACT

The stability and rheology of an Egyptian Heavy crude oil-in-water emulsions stabilized by an anionic (TDS) and a nonionic (NPE) surfactants individually or in a mixture have been studied. The study reveals that, the viscosity of the crude oil decreases when it is emulsified with water in the form of an oil-in-water type of emulsion. The stability of the oil-in-water emulsion increases as the surfactant concentration and speed of mixing of the emulsion increases. Fresh water and synthetic formation water have been used to study the effect of aqueous phase salinity on the stability and viscosity of the emulsion. Surfactant dissolved in synthetic formation water has been utilized to find out the possibility of injecting the surfactant into a well bore to effect emulsification in the pump or tubing for enhancing the production of heavy crude oils as oil-in-water emulsion. The study revealed that, the viscosity of the emulsion containing fresh water is always less than that containing formation water, these findings have been correlated with the crude oil/water interracial tension (IFT) measurements The decreased IFT value results in a decrease in the average particle size of the dispersed crude oil leading     

Effects of hydrocarbon solvents on simultaneous improvement in displacement and sweep efficiencies during CO2-enhanced oil recovery

The addition of hydrocarbon solvent such as liquefied petroleum gas (LPG) to the CO₂ stream leads to miscible conditions in reservoirs at lower pressures by reducing the minimum miscibility pressure (MMP). Under miscible conditions, improved displacement and vertical sweepout occur simultaneously. The influences of LPG concentration and composition on the displacement and sweep efficiencies during CO₂-LPG enhanced oil recovery (EOR) were investigated. Enhanced displacement efficiency was assessed through oil viscosity reduction and oil saturation change. Moreover, the miscible flooding induced by LPG addition, which resulted in increased solvent viscosity and a lower density difference between the injected fluid and reservoir oil, provided a smaller viscous gravity number, and improved the sweep efficiency, alleviating the impact of solvent gravity override. For CO₂-LPG EOR, oil recovery increased up to 52% as compared with that for CO₂ flooding. The amount of incremental oil recovery with 100% butane in the LPG was 16%, as compared with the 100% propane case. Mitigated gravity override enabled CO₂-LPG EOR to enhance sweep efficiency. Results indicated that the compositional modeling of the EOR process with the addition of LPG provided more accurate prediction on the performance of CO₂-LPG EOR.     

不同浓度组分可控烷基苯磺酸盐弱碱三元体系乳化规律

三元驱油体系在地层运移过程中化学药剂浓度发生变化,使得三元驱油体系与原油乳化特性也发生改变。针对组分可控烷基苯磺酸盐弱碱三元体系在地层运移过程中与原油的乳化特性开展实验研究。结果表明：使用均化仪对体系及原油进行乳化后,组分可控烷基苯磺酸盐弱碱三元体系中聚合物浓度越低,乳化后体系黏度增幅倍数越大;乳化后三元体系界面张力变化不大,Zeta电位小幅下降,乳状液类型以油/水型为主;三元体系乳化析水率、乳化特性变化明显,其原因是表面活性剂的分子结构影响较大,与界面张力及Zeta电位关系不大。正交实验方法分析了组分可控烷基苯磺酸盐表面活性剂、碳酸钠及中等相对分子质量聚合物这3种不同类型化学药剂对组分可控烷基苯磺酸盐弱碱三元体系乳化特性的影响规律。方差分析结果表明：影响乳状液黏度因素由大到小的顺序为：聚合物、弱碱、表面活性剂,当聚合物质量浓度为600 mg/L时,乳状液黏度增幅倍数最大;影响乳化析水率的因素由大到小的顺序为：弱碱、表面活性剂、聚合物,当Na₂CO₃质量分数为0.3%、表面活性剂质量分数为0.3%、聚合物质量浓度为1000 mg/L时,乳化体系在24 h时的乳化析水率最低,乳化特性最明显。     

基于能量及原油物性定量分析的油-水混合液黏度预测模型

高含水油-水混合液往往不能形成稳定的乳状液,而是原油将其中一部分水乳化,形成了油包水(W/O)乳状液液滴和游离水的掺混体系.传统的乳状液黏度模型并不适用于这种非稳定乳化的油-水混合体系.采用搅拌测黏法测定并研究了搅拌转速、含水率及温度对油-水混合液表观黏度的影响.结果表明:油-水混合液的表观黏度随着搅拌速率的增大、含水...