Characterization of Physico-Chemical Properties of Oil/Water Systems: Interfacial Behavior Prediction

Abstract

The tractability of petroleum is intimately related to the type of emulsion that is formed during its production. The characteristics of water/oil and oil/water emulsions depend on some factors such as the density and the composition of the oil. In this work, the properties of oils coming from the Campos Basin, Brazil, were evaluated by means of water-in-oil emulsion physico-chemical, interfacial, and characterization tests. Such properties have been correlated with the tractability of the petroleum in order to establish a behavior prediction method based on the properties of such petroleum. The main tool used in this work was the chemiometry technique. Through this method, it was possible to conclude that density, viscosity, surface tension, and nickel content were the properties that influenced the separation of the oils. Density, pour point, initial temperature of crystal formation (TIAC), characterization factor, and nitrogen content were the properties that influenced the diameter of the emulsion drops.     

Effect of Alkali on Daqing Crude Oil/Water Interfacial Properties

Alkaline-surfactant-polymer(ASP)flooding using sodium hydroxide as the alkali component to enhance oil recovery in Daqing Oilfield,northeast China has been successful,but there are new problems in the treatment of produced crude.The alkali added forms stable water-in-crude oil emulsion,hence de-emulsification process is necessary to separate oil and water.The problems in enhanced oil recovery with ASP flooding were investigated in laboratory by using fractions of Daqing crude oil.The oil was separated into aliphatics,aromatics,resin and asphaltene fractions.These fractions were then mixed with an additive-free jet fuel to form model oils.The interfacial properties,such as interfacial tension and interfacial pressure of the systems were also measured,which together with the molecular parameters of the fractions were all used to investigate the problems in the enhanced oil recovery. In our work,it was found that sodium hydroxide solution reacts with the acidic hydrogen in the fractions of crude oil and forms soap-like interfacially active components,which accumulate at the crude oil-water interface.     

EOR化学剂对原油／水体系的界面流变性的影响

在较大温度和剪切速率范围内研究了不同的匈牙利原油 /水体系的界面流变性情况 ,分别讨论了原油 /水体系中无机电解质、水溶性聚合物、非离子表面活性剂和碱性物质对界面流变性的影响。大量的室内实验结果证明 ,界面性质对非混相地层流体的化学组成十分敏感。因此 ,研究界面流变性质对于开拓油藏描述方法 ,了解驱替机理 ,设计更有利的EOR方法 ,强化地面工艺 ,优化管道输送以及改善炼油作业都有着十分重要的意义。     

Particle Characterization for Oil Sand Processing. III. Sample Preparation

Abstract

The procedures used to prepare laboratory samples of solids from oil sand processing streams for particle size measurements by laser diffraction are discussed. The method used to clean bitumen from the sample significantly influences the physical form of the cleaned solids. However, clay particles in the solids are effectively dispersed in water using an ultrasonic probe and this technique gives consistent particle size determinations irrespective of the method used to clean the solids. The uncertainties in the measurement are evaluated and it is concluded that most of the variation arises from subsampling the solids. However, the procedures described in this article are shown to give excellent repeatability.     

Particle Characterization for Oil Sand Processing. III. Sample Preparation

The procedures used to prepare laboratory samples of solids from oil sand processing streams for particle size measurements by laser diffraction are discussed. The method used to clean bitumen from the sample significantly influences the physical form of the cleaned solids. However, clay particles in the solids are effectively dispersed in water using an ultrasonic probe and this technique gives consistent particle size determinations irrespective of the method used to clean the solids. The uncertainties in the measurement are evaluated and it is concluded that most of the variation arises from subsampling the solids. However, the procedures described in this article are shown to give excellent repeatability.     

十二烷基甜菜碱／脂肽复配体系与原油界面行为的研究

在50℃下以3-磺丙基十二烷基二甲基甜菜碱(SDDAB)为主要组分,分别考察了SDDAB/碱、SDDAB-脂肽/碱二元(AS)和ASP三元复合体系与原油之间的动态界面张力。在SDDAB/碱体系中,不同碱降低界面张力的能力顺序为NaOH>Na2SiO3>Na2CO3>NaHCO3;不同复配弱碱降低界面张力的顺序为Na2CO3-Na2SiO3>Na2SiO3-NaHCO3>Na2CO3-NaHCO3。Na2CO3-Na2SiO3的碱性弱于NaOH,降低界面张力的效果优于强碱NaOH,最低界面张力值可达0.00405 mN/m,界面张力稳定值在10-310-2mN/m数量级之间。在Na2CO3-Na2SiO3加量12 g/L,表面活性剂加量0.5 g/L条件下,SDDAB、脂肽质量比为1:1时的协同作用明显,界面张力最低值可达10-4mN/m数量级。碱对界面张力的影响是双向的。对于SDDAB-脂肽/Na2CO3-Na2SiO3二元复合体系,碱加量为12 g/L时的界面张力最低。在该二元体系中加入HPAM(M=2.5×107),界面张力随着HPAM浓度的增加而升高;当HPAM加量为0.4 g/L时,ASP三元体系的动态界面张力仍在10-3mN/m数量级,为性能最佳体系。     

Dynamic Interfacial Tension Between Gudao Heavy Oil and Petroleum Sulfonate/HPAM Complex Systems

Abstract

The dynamic interfacial tension between Gudao heavy oil and petroleum sulfonate/hydrolyzed polyacrylamide complex system was studied. It is shown that with the addition of hydrolyzed polyacrylamide into the solution of petroleum sulfonate, not only is the viscosity of the complex system increased, but also the dynamic interfacial tension is further lowered. Thus a complex system with high viscosity and low interfacial tension can be constituted by 0.3 wt% petroleum sulfonate and 0.18 wt% hydrolyzed polyacrylamide with a viscosity-averaged molecular weight of 1 × 10⁷. In addition, the dynamic interfacial tension between complex system and crude oil can also be lowered by increasing the salt content in solution.     

油／水界面张力快速测定方法的研究及应用

为了简便、快速、可靠地测定表面活性剂对原油/水界面张力的影响,室内根据滴体积法原理建立了一套快速测定油/水界面张力的装置,并对该装置测定结果的影响因素、平行性及可靠性进行了检验。结果表明,滴落速度对测定结果的影响较大,滴落速度应≥5秒/滴。该方法平行性较好,相对误差小于2%,苯/水体系测定误差小于1%,可以用于测定油/水体系界面张力。室内用该方法考察了生物表面活性剂、鼠李糖脂工业品、化学防蜡剂加量对原油/水界面张力的影响,得到3种药剂的最佳加药量分别为5%、4%、4%,相同加量下的药剂界面活性顺序为:化学防蜡剂>生物表面活性剂>鼠李糖脂工业品。图1表5参4     

Hydroxysulfobetaine/Hydrolyzed Polyacrylamide Complex Systems for Gudao Heavy Oil Recovery: A Dynamic Interfacial Tension Study

Abstract

A complex system that consists of hydroxysulfobetaine and hydrolyzed polyacrylamide has been studied. It is indicated that the complex system is of high viscosity and can reduce the interfacial tension between Gudao heavy oil and solution to ultra-low value. The interfacial tension of complex system in formation water is influenced simultaneously by the concentration of polymer and the salt content. The adsorption experiment shows that hydrolyzed polyacrylamide can prevent hydroxysulfobetaine from being adsorbed on the quartz sands excessively. It can be concluded that the hydroxysulfobetaine/hydrolyzed polyacrylamide complex system is capable of satisfying the requirements of displacement system for EOR.     

Experimental Investigation of Surfactant Partition in Heavy Oil/Water/Sand Systems

Abstract

Surfactant adsorption on reservoir rocks or sands is one of the major factors that may significantly reduce the effectiveness of an alkaline/surfactant flood for oil recovery. It is difficult to determine the surfactant adsorption by measuring the difference between surfactant concentrations before and after adsorption when the water phase contains fine oil drops. In this study, an extraction method was used to quantitatively determine the adsorptions of surfactant on sand and at oil-water interfaces in an alkaline/surfactant flood for heavy oil recovery. Experimental results showed that the formation of emulsions dramatically reduced surfactant loss to sand surface. The adsorptions of surfactant on sand and at oil-water interface were determined under various alkaline concentrations and salinities. The results provide useful information for evaluating and predicting surfactant adsorption in alkaline/surfactant flooding for enhanced heavy oil recovery.     

基于原油物性定量表征的油包水乳状液黏度预测模型

准确预测原油乳状液的黏度对于油水混输管道的设计和运行具有重要意义。将8种不同物性的原油制备成油包水乳状液,通过流变仪对乳状液的黏度特性进行测定,研究了温度、含水率及剪切速率对油包水乳状液表观黏度的影响。以实验数据为基础,并对原油物性进行定量表征,建立了适用于不同原油、不同剪切条件的油包水乳状液黏度预测模型。结果表明,油包水乳状液的表观黏度随温度的升高而减小,随含水率的增加而增大,随剪切速率的增加而减小;具有剪切稀释性,可采用幂率模型来描述油包水乳状液的流变特性。随着含水率上升,油包水乳状液的稠度系数（K）逐渐增大,而流变特性指数（n）逐渐减小;随着温度升高,K逐渐减小,而n逐渐增大。油包水乳状液黏度预测模型的最佳适用条件为：乳状液体积含水率0.30～0.60、温度30～60℃、乳状液黏度10～2000 mPa·s。该模型计算黏度值与实测值之间的平均相对偏差为8.1%,预测效果良好。     

烃-水/盐水体系高压界面张力的测定与关联

应用ＪＥＦＲＩ悬滴式界面张力仪，在１—３０ＭＰａ压力范围内，测定了２５℃、５０℃下６种正构烷烃与水及无机盐水溶液间的高压界面张力。在改进Ｎａｋａｈａｒａ－Ａｒａｉ关联式的基础上，根据试验得到的界面张力压力系数，提出了计算烃－水／盐水体系高压界面张力的方程。对１５０个数据点的考核表明：与试验值相比，平均相对误差仅为０．６７％。     

原油组分对驱油体系界面性质影响的研究

对大庆油田不同地区原油族组成进行了分析,并测量了胶质沥青质含量不同的原油与三元体系间的界面张力。结果表明,将原油分离出的各组分分别与氢氧化钠溶液、表面活性剂ORS41及三元复合体系作用,其界面张力有明显的差别,这说明在与三元驱油体系形成超低界面张力时,原油性质也有非常重要的影响。     

Maltenes and Asphaltenes of Petroleum Vacuum Residues: Physico-Chemical Characterization

Solvent separation is frequently applied to petroleum vacuum residues to reduce the coke-forming tendencies of these materials. This process is capable of removing all or a substantial amount of asphaltenes from feedstocks that are destined for further processing and thus applied as the first step of refining. Maltenes and asphaltenes obtained from vacuum residues of Heera (HVR) and Jodhpur (JVR) Indian crude oils using n-hexane, n-heptane, and soluble and insoluble fractions obtained using ethyl acetate, were characterized for elemental analysis, molecular weight, conradson carbon residue (CCR), specific gravity, and pour points. The resulting degree of removal of asphaltenes ranged from 10-28 wt% of the HVR and 25-50 wt% of the JVR. The increasing trend of the American Petroleum Institute (API) gravity and the decreasing trend of CCR and pour point are observed with the increase in removal of asphaltenes.     

Maltenes and Asphaltenes of Petroleum Vacuum Residues: Physico-Chemical Characterization

Abstract

Solvent separation is frequently applied to petroleum vacuum residues to reduce the coke-forming tendencies of these materials. This process is capable of removing all or a substantial amount of asphaltenes from feedstocks that are destined for further processing and thus applied as the first step of refining. Maltenes and asphaltenes obtained from vacuum residues of Heera (HVR) and Jodhpur (JVR) Indian crude oils using n-hexane, n-heptane, and soluble and insoluble fractions obtained using ethyl acetate, were characterized for elemental analysis, molecular weight, conradson carbon residue (CCR), specific gravity, and pour points. The resulting degree of removal of asphaltenes ranged from 10–28 wt% of the HVR and 25–50 wt% of the JVR. The increasing trend of the American Petroleum Institute (API) gravity and the decreasing trend of CCR and pour point are observed with the increase in removal of asphaltenes.     

基于能量及原油物性定量分析的原油乳化含水率预测模型

 原油-水两相体系的乳化特性与原油物性密切相关,以流动状态下的原油乳化含水率来表征原油-水两相体系的乳化特性,针对高含水原油-水两相体系,通过实验研究了乳化过程消耗的机械能对原油乳化含水率的影响。研究表明,不同剪切条件下的原油乳化含水率可以与消耗的机械能进行定量关联,并且可以采用幂律关系式进行描述,该关系式中的2个待定参数与原油物性密切相关。确定了用沥青质胶质含量、蜡含量、机械杂质含量、原油酸值、原油全烃平均碳数这5个典型参数来表征原油物性。通过回归分析,建立了待定参数与原油物性之间的定量关系,从而确定了原油乳化含水率的预测模型,即φE=c₁E^c2。     

Properties Correlations and Characterization of Athabasca Oil Sands-derived Synthetic Crude Oil

Narrow fractions of Athabasca oil sands-derived synthetic crude oil (SCO) from Canada were obtained by distillation at 20 oC to 500 oC and characterized. The yield and properties, such as density, refractive index, viscosity, freezing point, sulfur and nitrogen content and UOP K-index, were correlated as a function of boiling temperature (Tb). The properties of naphtha fractions, jet fuel and diesel fractions could be predicted accurately with the correlations, which are useful for process design considerations, such as optimizing operating conditions of refinery processing units. The other key properties and characteristics of naphtha fractions, jet fuel, diesel and vacuum gas oil were also determined.     

单家寺稠油降粘剂SJ及其O/W型乳状液流变性研究

报道了乳化降粘剂SJ对单家寺稠油的乳化降粘作用。SJ为含少量无机碱和盐的石油磺酸盐、非离子表面活性剂的混合物 ,在 30 0℃、3.4 5MPa下热处理 2 4h后使用。实验油样为单家寺一口井所产超稠油 ,含胶质 31.9% ,含沥青质 9.1% ,酸值 1.83mgKOH/g油 ,5 0℃、1.2s-1粘度 6 3.4Pa·s。水样为该油田采出水 ,矿化度 19.5 g/L。在大范围内变化SJ加量和油水体积比 ,求得乳化剂在水中的最佳加量为 0 .3%～ 0 .5 % ,最佳油水比为 80∶2 0～70∶30 ,所得O/W型稠油乳状液 5 0℃、1.2s-1下的粘度为 4 2 0～ 180mPa·s,在 5 0℃放置 90min后脱水率 >92 %。SJ的乳化降粘性能和形成的乳状液稳定性均符合稠油生产要求。在 6 0℃、剪切速率 5 0～ 12 0 0s-1范围考察了SJ用量 0 .3%、油水比 80∶2 0～ 2 0∶80的 5个O/W乳状液的粘度 剪切速率关系 ,发现乳状液的粘度均随剪切速率增大而减小 ,在剪切速率 >10 0 0s-1后不再变化 ,但假塑性随油水比减小而减小。在 30～ 70℃范围乳状液流变性变化规律相似。图 1表 2参 3     

郑王稠油四组分组成和油-水界面膜黏弹性的关系

采用化学分离和元素分析方法分析了郑王稠油的饱和分、芳香分、胶质、沥青质（SARS）的组成,测定了含有分离的四组分的油 水体系的界面扩张黏弹性,考察了振荡频率及组分浓度对油 水体系界面扩张黏弹性的影响。结果表明,含郑王稠油四组分的油 水体系的界面扩张模量均随振荡频率增大而增大,随组分质量分数的增大先增加后减小。含胶质、沥青质组分的油 水体系所形成的界面膜以弹性膜为主,抵抗形变能力更强;油 水体系中饱和分浓度增大,主要体现在其体相浓度增加,弹性模量变化不大,而黏性模量逐渐增大。含郑王稠油四组分的油 水体系的扩张相角均随振荡频率的增加逐渐减小,扩张相角由小到大的油 水体系为含沥青质的、含芳香分的、含胶质的、含饱和分的油 水体系。沥青质是四组分中对油 水体系界面膜黏弹性影响最大的组分。       

Phase Behaviour and Physical Properties of Alkane Solvent(s)/CO2/N2/DME/Water/Heavy Oil Systems under Reservoir Conditions

The hybrid steam-solvent injection has been considered as a promising technique for enhancing heavy oil/bitumen recov‐ery,while its main mechanisms including the heat transferred and dissolution of solvents (e.g.,CH₄,C₂H₆,C₃H₈,C₄H₁₀,CO₂,N₂,and DME) into heavy oil/bitumen to reduce its viscosity and swell it are closely related to the phase behaviour of the solvents/water/heavy oil systems.To allow ...