VISCOSITY OF WATER IN OIL EMULSIONS

ABSTRACT

Increase in water cut in oil fields generally calls for an increase in the capacity of transport pipelines. Proper design and operation of the latter requires good knowledge of the thermophysical properties of flow resistance of crude-oil water mixtures. An experimental program aimed at measurements of oil-water emulsion viscosity for water cuts prior to the inversion point was conducted.

The present work reports on measurements of Nimr crude oil-water mixtures viscosity for different water cuts and a typical range of temperatures representative of field conditions (20°-50°C). Three mixing intensities of 10⁶, 5×10⁶ and 15×10⁶ erg/cm-sec generated by a dynamic coalescer and directly relevant to field conditions were used.

The results suggest that the inversion point occurs around a value of water cut of 35%. Both Newtonian and non-Newtonian (pseudo-plastic) behaviour were observed, and the ASTM viscosity model is found to be applicable to the emulsions. The effect of the mixing intensity on the resulting emulsion viscosity was found to be important at low temperatures and decreased at high temperatures. The experimental data fitted the available correlations in the literature.     

VISCOSITY OF WATER IN OIL EMULSIONS

Increase in water cut in oil fields generally calls for an increase in the capacity of transport pipelines. Proper design and operation of the latter requires good knowledge of the thermophysical properties of flow resistance of crude-oil water mixtures. An experimental program aimed at measurements of oil-water emulsion viscosity for water cuts prior to the inversion point was conducted.

The present work reports on measurements of Nimr crude oil-water mixtures viscosity for different water cuts and a typical range of temperatures representative of field conditions (20°-50°C). Three mixing intensities of 10⁶, 5×10⁶ and 15×10⁶ erg/cm-sec generated by a dynamic coalescer and directly relevant to field conditions were used.

The results suggest that the inversion point occurs around a value of water cut of 35%. Both Newtonian and non-Newtonian (pseudo-plastic) behaviour were observed, and the ASTM viscosity model is found to be applicable to the emulsions. The effect of the mixing intensity on the resulting emulsion viscosity was found to be important at low temperatures and decreased at high temperatures. The experimental data fitted the available correlations in the literature.     

VISCOSITY BEHAVIOR: CORRELATION OF WATER-IN-OIL EMULSIONS IN PRESENCE OF SOLIDS

This is a study of viscosity behavior of oil-water emulsions-solid mixtures. It uses three oils in the presence of different volume fractions (0.005 - 0.02) of fine solids that have different affinities for water. It has been revealed that suspensions and emulsion-solid mixtures of each oil have identical viscosity at the same shear rate. This is an indication that emulsions behave as continuous phase, whilst solids behave as dispersed phase. Consequently, it is possible to correlate the relative viscosity (η_r) data with formulas available in literature for predicting the viscosity of suspensions and emulsions. Relative viscosity is defined as the emulsion-solid mixture viscosity over the pure emulsion viscosity. It has also been found out that Richardson equation [η_r = exp(a ϕ_s)] with values of 80 and 87 for the parameter a, fits the relative viscosity data of the two light oils used and the heavy one, respectively. The emulsion-solid mixtures prepared in the presence of both hydrophobic and hydrophilic solids were correlated by the same model. Furthermore, The viscosity of pure emulsions of two of the oils studied was found to fit both Krieger's hard sphere model and Roscoe's model but the third oil was found to fit Eilers' model.     

VISCOSITY BEHAVIOR: CORRELATION OF WATER-IN-OIL EMULSIONS IN PRESENCE OF SOLIDS

This is a study of viscosity behavior of oil–water emulsions-solid mixtures. It uses three oils in the presence of different volume fractions (0.005 – 0.02) of fine solids that have different affinities for water. It has been revealed that suspensions and emulsion-solid mixtures of each oil have identical viscosity at the same shear rate. This is an indication that emulsions behave as continuous phase, whilst solids behave as dispersed phase. Consequently, it is possible to correlate the relative viscosity (η_r) data with formulas available in literature for predicting the viscosity of suspensions and emulsions. Relative viscosity is defined as the emulsion-solid mixture viscosity over the pure emulsion viscosity. It has also been found out that Richardson equation [η_r = exp(a ?_s)] with values of 80 and 87 for the parameter a, fits the relative viscosity data of the two light oils used and the heavy one, respectively. The emulsion-solid mixtures prepared in the presence of both hydrophobic and hydrophilic solids were correlated by the same model. Furthermore, The viscosity of pure emulsions of two of the oils studied was found to fit both Krieger's hard sphere model and Roscoe's model but the third oil was found to fit Eilers' model.     

加清净剂柴油长期储存安定性的变化规律

在柴油中加入清净剂,采用ASTM D 4625方法,于43℃储存0d、84d、168d,测定柴油的实际胶质和总不溶物含量,采用方差分析和线性回归方法考察了实际胶质和总不溶物的影响因素及其变化规律。结果表明,加清净剂柴油在储存过程中,其实际胶质和不溶物的量主要由柴油本身性质和储存时间决定,清净剂的配方有一定程度的影响。随着储存时间延长,加清净剂柴油的实际胶质和不溶物均呈线性递增,递增速率主要由柴油本身性质决定。加清净剂柴油的实际胶质(不溶物)与空白柴油实际胶质(不溶物)之间呈线性关系。各种清净剂对柴油储存安定性能影响不同。43℃储存168d后实际胶质和总不溶物变化率范围分别为 8.6%~40.1%和-37.9%~76.2%。结合改善柴油储存安定性能和优选性能优异清净剂的两种方式,可以实现加清净剂柴油长期储存。     

一种广谱型支状油溶性降黏剂的研制

针对稠油胶质、沥青质含量高,黏度和凝点高,给其开采和运输带来困难的情况,以丙烯酸异构酯、苯乙烯、马来酸酐为聚合单体,甲苯为溶剂,过氧化二苯甲酰为引发剂,制备了一种广谱型支状油溶性降黏剂（YGZ型油溶性降黏剂）,对制备条件进行优化,考察其对多种油品的降黏效果,并对其降黏机理进行初步分析。结果表明：YGZ型油溶性降黏剂的适宜制备条件为：共聚物单体丙烯酸异构酯、马来酸酐、苯乙烯的摩尔比为5:1:3,过氧化二苯甲酰加入量（w）1.0%,反应温度90 ℃,反应时间6 h;该降黏剂可使黏度（50 ℃）为2 106 mPa?s的伊拉克原油黏度下降70.4%;含有支链结构的异构型降黏剂的降黏效果比正构型降黏剂好;该降黏剂具有较好的广谱性,可用于多种稠油降黏。     

加清净剂汽油长期储存清净性能的变化规律

 采用模拟进气阀沉积物试验方法，详细考察了加清净剂汽油长期储存清净性的影响因素和变化规律。结果表明，加清净剂汽油长期储存的清净性主要受储存时间（t）和汽油种类影响。无论是空白汽油还是加清净剂汽油，随着储存时间的延长，清净性变差，进气阀沉积物生成量（m_IVD）呈线性递增，即m_IVD =k×t+b，k为m_IVD的变化速率。加清净剂汽油的k与空白汽油的k呈线性关系，同时与汽油储存安定性密切相关。结合改善汽油储存安定性能和优选长期稳定性优异的清净剂两种方式，可以防止加清净剂汽油长期储存清净性显著降低，实现加清净剂汽油长期储存使用。     

HG系列降粘剂对宁一联原油乳状液流变性的影响

研究了ＨＧ系列降粘剂对不同含水率的华北油田宁一联原油乳状液流变性的影响。ＨＧ系列降粘剂为华北油田常用降粘剂，其主剂为多乙烯多胺起始的嵌段聚醚表面活性剂。研究结果表明，在含水率１０％－６０％的宁一联原油乳状液中加入ＨＧ降粘剂民状液流变行为指数ｎ增大，稠度系数ｋ减少，粘度降低，低温屈服值减小，凝点降低，转相点降低；降粘剂对不含水原油和含水率≤１０％的原油乳状液无效；降粘剂的效果随含水率增大而增大。对于     

微乳化降黏方法制备调合型船用燃料油

采用减压渣油、重质蜡油、乙烯焦油为原料调合船用燃料油,当m（减压渣油）：m（重质蜡油）：m（乙烯焦油）为5:2:3及3:4:3时,调合燃料油分别达到RMG380及RME180船用燃料油黏度指标。为了充分利用高黏度渣油资源及提高调合燃料油的稳定性,选取m（减压渣油）：m（重质蜡油）：m（乙烯焦油）为5:3:2的调合油进行微乳化降黏研究,结果表明：JM型降黏剂与丙二醇嵌段聚醚L61复配作为降黏剂,调合油的运动黏度（150 ℃）由520.5 mm2/s降到334.1 mm2/s;同时,加入抗氧剂264,在90天的跟踪考察下,油品不分层,调合油运动黏度（150 ℃）为348.9 mm2/s,符合RMG380船用燃料油黏度要求,并且比其它普通油溶性降黏方法调配燃料油的成本降低21.28%。     

改善中等粘度指数基础油质量的几种方法

针对中间基原油的特点,从油品的结构和组成论述了润滑油的粘度指数、氧化安定性与组成的关系以及采用调合、脱氮、缓和加氢处理工艺来改善中等粘度指数基础油质量的几种方法。其中润滑油缓和加氢处理工艺既能适当提高油品的粘度指数,又能改善其氧化安定性。     

加氢基础油生产高粘度白油技术

针对国内润滑油加氢技术应用特点，石油化工科学研究院研制了贵金属型精制催化剂RLF-10W，开发了以加氢基础油为原料经加氢精制(一段法)生产优质白油技术。经固定床加氢中型装置试验和一年来的实际应用，结果表明．该技术具有流程简单，适应性强等特点，特别适合于生产高粘度与很高粘度优质白油。     

由粘度和密度计算重油的相对分子质量

采用（１） ２０ ℃时的密度和８０ ℃时的粘度;（２） ２０ ℃时的密度和１００ ℃时的粘度;（３）２０ ℃时的密度、８０ ℃时的粘度和１００ ℃时的粘度作参数,分别得到三种计算重馏分油数均相对分子质量的关联式,其适用范围为２００～８００,平均相对误差４％ 左右。还采用８０ ℃时的粘度、１００ ℃时的粘度和２０ ℃时的密度作参数得到计算常压渣油和减压渣油的数均相对分子质量的关联式,适用范围为３００～１ ４００,平均相对误差５．３％ 左右。     

三次采油中水包油乳状液的超声波破乳

对超声波破乳、粒子运动和碰撞的机理进行了分析,利用可视化技术对超声波作用下拉子运动的位移效应进行了验证。给出了悬浊液中粒子的碰撞水动力学模型和合并条件。针对胜利油田孤岛采油厂三次采油中采出的水包油型乳化原油进行了超声波破乳脱水实验研究,证明了超声波破乳分离水包油乳状液的可行性。温度为55℃时,在最优实验条件下超声波与破乳剂联合处理30min,沉降4h,可以脱去乳化原油中96.5%的水,而在同样条件下不用超声波处理的原油脱水率仅有73%。     

含烷氧基链节的硫酸盐表面活性剂的油-水界面张力及其对原油的乳化能力

 以壬基酚、十二醇、异构十三醇为主要原料，合成了7种含烷氧基链节的硫酸盐表面活性剂。测定了以含0.1%(质量分数) 硫酸盐表面活性剂的模拟盐水与桩106-15-X18普通稠油配制的油-水体系的界面张力，并测定了上述表面活性剂对桩106-15-X18普通稠油的乳化速率。结果表明，虽然这些表面活性剂具有较高的耐盐能力，但随着分子中氧丙烯链节数逐渐增加，油-水界面张力值最小时对应的最佳NaCl含量呈降低趋势。在合成含烷氧基链节的硫酸盐表面活性剂时，可以通过控制氧丙烯链节长度，调节其在油-水体系中获得的低界面张力区的特点，使之适应不同盐含量的地层。含烷氧基链节的硫酸盐表面活性剂降低油-水界面张力的能力和其对稠油的乳化速率没有简单的对应关系。     

低相对分子质量聚丙烯酸钠的制备

以丙烯酸、氢氧化钠为原料,以过硫酸铵为引发剂,以亚硫酸氢钠为链转移剂合成了低相对粘均相对分子质量聚丙烯酸钠。采用正交实验法,得到合成相对分子质量为2 000～4 000的聚丙烯酸钠的最佳工艺条件为:反应时间2.5h,反应温度55℃、丙烯酸浓度35%、过硫酸铵用量4%、亚硫酸氢钠用量6%。     

以残渣油组分为原料制备高性能电流变液的研究

研究了残渣油组分及其热转化产物作为分散相的电流变液特性,发现未经热转化的残渣油组分具有负电流变效应,而经热转化达到一定深度的残渣油组分具有电流变效应,并存在一最佳的C/H原子比.考察了石油中间相沥青基电流变液的性能,结果表明,以残渣油为原料制备的碳素粒子电流变液是一种具有较高应力水平、良好抗剪切性能、低能耗和良好耐温能力的新型电流变液材料.     

核-壳法制备纳米银中空微粒

采用核-壳法制备纳米银中空微粒,用透射电镜、扫描电镜分析了单质Ag、Ag/PS、Ag/PS/Ag微粒的结构,并探讨了苯乙烯、乳化剂及Ag+加入量对微粒包裹程度和规整度的影响。实验结果表明:当AgNO3用量为0.002mol,苯乙烯加入量为3mL,乳化剂加入量为0.4g,Ag+加入量为0.002mol时,可制得包裹完善、外形规整复合微粒,最后用高温煅烧的方法,可制备具有中空结构的纳米银核-壳粒子。     

具有黏度改性功能的聚异丁烯基抗氧化剂的合成与评价

以高活性低相对分子质量聚异丁烯和3-（3,5-二叔丁基-4-羟基苯基）丙酸甲酯为原料,合成了具有黏度改性作用的聚异丁烯基抗氧化剂。所得产物的傅立叶变换红外光谱分析结果与目标产物结构吻合。TG分析结果表明,合成的聚异丁烯基抗氧化剂比聚异丁烯具有更好的热稳定性,起始氧化温度提高40 ℃。旋转氧弹测试结果表明,合成的聚异丁烯基抗氧化剂具有良好的抗氧化作用,添加量（w）为0.5%时可将矿物油的氧化诱导期从27 min延长至84 min,明显提高了油品的氧化安定性。在矿物油中加入量（w）为5.0%时,油品的黏度指数从114提高到132,说明该聚异丁烯基抗氧化剂在改善油品黏度方面具有积极作用。     

柴油-甲醇-水三元乳化液W/O的流变特性

研究了柴油-甲醇-水三元W/O乳化液流变特性与乳化剂的种类、含量以及乳化液组分的关系。结果表明,在本实验采用的组分配比下,柴油-甲醇-水三元W/O乳化液近似为牛顿流体,而且乳化剂的种类、含量以及乳化液中柴油的量均对乳化液的流变特性具有显著的影响。对于组分组成相同的柴油-甲醇-水三元W/O乳化液,其黏度随着乳化剂含量及其黏度的增加而增大。当柴油-甲醇-水三元W/O乳化液中甲醇与水的比例一定时,减少柴油的质量分数,乳化液的黏度增大。当乳化剂含量相同时,柴油-甲醇-水三元W/O乳化液的黏度随着其中水含量的增加而增大。