LOW TEMPERATURE FLOW CHARACTERISTICS OF SOME WAXY CRUDE OILS IN RELATION TO THEIR COMPOSITION : PART II EFFECT OF WAX COMPOSITION AND CONCENTRATION ON THE DEW AXED CRUDE OILS WITH / WITHOUT ADDITIVES

ABSTRACT

In this part of the work the effect of wax concentrations on the rheologica! properties of the dewaxed Duliajan (Assam) and Lingaia crude oils have been studied. The dewaxing of the crude oil was done by removing n-paraffins from the crude oil by urea adduction. The urea adducted n-paraffins concentrate-the wax- was characterized by its carbon number distribution. The urea non adducted oil portion - the denormalized crude oil (DNO)- was characterized for its pour point. The wax in different concentration was then added in the DNO and the change in the rheological properties like pour point, yield stress and plastic viscosity were studied using a Haake Rota Viscometer. The effect of carbon number distribution, i.e. the composition of the wax, on these rheological properties was also investigated. Four different commercial pour point depressanl additives have been used to study their effects on the pour point, yield stress and plastic viscosity of the reconstituted (wax mixed DNO) crude oils.

From this study it has been found that wax concentration and its composition are primarily responsible for the variation in the pour point of the DNO, and the DNO composition has a small effect. However, as seen in the Part I of this paper, the response of the pour point depressant additive in effecting the change in the pour point is primarily governed by the composition of the DNO. The additives have shown better response in the DNO having more aromatic concentrate, as has been found in the case of Duliajan (Assam) DNO.     

LOW TEMPERATURE FLOW CHARACTERISTICS OF SOME WAXY CRUDE OILS IN RELATION TO THEIR COMPOSITION : PART I WITH AND WITHOUT POUR POINT DEPRESSANT ADDITIVES

The yield stress, plastic viscosity and apparent viscosity and the dependence of the latter on the shear rate have been studied at different temperatures below pour point of Lingala (Krishna-Godavari basin, Eastern coast), Duliajan (Eastern region of Assam), Rava (Godavari basin) and Bombay-High (off-shore western region) indigenous crude oils

Four different commercial pour point depressant additives have been used to study their effects on the pour point, yield stress and plastic viscosity

From this study it has been found that wax concentration and its composition are primarily responsible for the variation in the pour point, and crude base composition has a small effect. However, the response of the pour point depressant additive in effecting the change in the pour point is primarily governed by the liquid matrix. As the temperature is lowered both the yield stress and plastic viscosity increase in case of each crude oil. However, the magnitude is dependent on the nature of the crude oil. With pour point depressant additives, the yield stress and plastic viscosity are decreased and this decrease is a function of nature of the liquid matrix of the crude oil and concentration of the additive     

LOW TEMPERATURE FLOW CHARACTERISTICS OF SOME WAXY CRUDE OILS IN RELATION TO THEIR COMPOSITION : PART I WITH AND WITHOUT POUR POINT DEPRESSANT ADDITIVES

ABSTRACT

The yield stress, plastic viscosity and apparent viscosity and the dependence of the latter on the shear rate have been studied at different temperatures below pour point of Lingala (Krishna-Godavari basin, Eastern coast), Duliajan (Eastern region of Assam), Rava (Godavari basin) and Bombay-High (off-shore western region) indigenous crude oils

Four different commercial pour point depressant additives have been used to study their effects on the pour point, yield stress and plastic viscosity

From this study it has been found that wax concentration and its composition are primarily responsible for the variation in the pour point, and crude base composition has a small effect. However, the response of the pour point depressant additive in effecting the change in the pour point is primarily governed by the liquid matrix. As the temperature is lowered both the yield stress and plastic viscosity increase in case of each crude oil. However, the magnitude is dependent on the nature of the crude oil. With pour point depressant additives, the yield stress and plastic viscosity are decreased and this decrease is a function of nature of the liquid matrix of the crude oil and concentration of the additive     

复合型原油降凝降粘剂EMS的研制

由ＥＶＡ、ＭＶＡ和表面活性剂复配成功了一种复合型降凝降粘剂ＭＥＳ，它对大庆、江汉和冀东石蜡基原油均有良好的降凝和降粘作用，对冀东沥青基稠油有一定降粘作用。本文了ＥＭＳ的研制和室内性能测定结果。     

RHEOLOGICAL PROPERTIES OF BOMBAY HIGH CRUDE OIL IN RELATION TO ITS n-ALKANE COMPONENTS

ABSTRACT

Bombay High crude oil is very waxy in nature and has a high pour point (30^°C), The wax present in it largely consists of solid n-alkanes. Changes in the rheological properties of the crude oil after removal of n-alkanes by urea adduction have been determined. Influence of the concentration of n-alkane components on the rheological properties of non adductable components of crude oil have also been studied.     

OCCURRENCE AND DISTRIBUTION OF n-ALKANESAND n-FATTY ACIDS IN SAUDI ARABIAN CRUDE OILS

Ten crude oil samples, covering wide range of maturity (API gravity = 18·5-36·1), were assembled from Safaniya, Abqiq, Ain Dar, Wafra. Marjan and Zuluf oil fields in the area of Arabian Gulf. n-Alkanes of were separated from the petroleum distillate ((150°C-450°C) of the crude oils by urea adduction. n-Fatty acids were separated from the fraction of n-alkanes by treatment with aqueous solution of KOH. Distribution of n-alkanes and n-fatty acids has been investigated by means of gas chromatography. The studied crude oils showed symmetrical distribution curves of n-paraffins and fatty acids of low molecular weight were abundant as compared with n-paraffins. The n-paraffins distribution curve of Wafra/Iucene biodegraded immature crude oil showed three maxima at C₁₇, C₁₉, and C₃₁ whereas the maxima of n-fatty acids are located at C₁₄,C₂₂and C₂₄. The results were interpreted in terms of origin, maturation and depositional environments of the crude oils.     

PARAFFIN DEPOSITION AND VISCOSITY TEMPERATURE BEHAVIOUR OF ASSAM CRUDE OIL

The rate of paraffin deposition at equilibrium under different flowing conditions, viz, flow rate, oil and cold surface temperatures, and also viscosity temperature behaviour of Assam crude having wax content 11·0 % wt. and pour point 30°C has been studied. The effect of various diluents viz commercial kerosene and diesel oil on paraffin deposition and viscosity temperature behaviour have been determined. Deposition data has also been quantified in the form of a regression equation. It has been observed that added solvent significantly effect the paraffin deposition and viscosity temperature behaviour.     

聚合物型原油降凝剂的结晶性能研究

摘要: 采用红外光谱仪、核磁共振波谱仪对聚合物的合成特征基团进行了表征，并采用X射线衍射仪对不同型号蜡及降凝剂的结晶性能进行了分析测试，结果表明蜡晶与聚合物的结晶性能密切相关，结晶度不同，蜡晶分散效果不同，对原油降凝性能也就有所区别，当两者结晶性能状态匹配时蜡晶分散效果变好，降凝降粘性能最佳，并通过考察原油体系热性能和低温流动性能进行了证实。     

BEM 系列原油流动性改进剂的应用

对BEM系列原油流动性改进剂的基本原理以及在中洛、濮临、东临、东黄、鲁宁、魏荆等几条原油长输管道工业应用的现场测试情况进行了介绍。结果表明，BEM系列原油流动性改进剂在降低原油凝点和粘度方面性能良好，能满足管道安全，平稳运行的要求。     

OCCURRENCE AND DISTRIBUTION OF n-ALKANESAND n-FATTY ACIDS IN SAUDI ARABIAN CRUDE OILS

ABSTRACT

Ten crude oil samples, covering wide range of maturity (API gravity = 18·5–36·1), were assembled from Safaniya, Abqiq, Ain Dar, Wafra. Marjan and Zuluf oil fields in the area of Arabian Gulf. n-Alkanes of were separated from the petroleum distillate ((150°C–450°C) of the crude oils by urea adduction. n-Fatty acids were separated from the fraction of n-alkanes by treatment with aqueous solution of KOH. Distribution of n-alkanes and n-fatty acids has been investigated by means of gas chromatography. The studied crude oils showed symmetrical distribution curves of n-paraffins and fatty acids of low molecular weight were abundant as compared with n-paraffins. The n-paraffins distribution curve of Wafra/Iucene biodegraded immature crude oil showed three maxima at C₁₇, C₁₉, and C₃₁ whereas the maxima of n-fatty acids are located at C₁₄,C₂₂and C₂₄. The results were interpreted in terms of origin, maturation and depositional environments of the crude oils.     

PARAFFIN DEPOSITION AND VISCOSITY TEMPERATURE BEHAVIOUR OF ASSAM CRUDE OIL

ABSTRACT

The rate of paraffin deposition at equilibrium under different flowing conditions, viz, flow rate, oil and cold surface temperatures, and also viscosity temperature behaviour of Assam crude having wax content 11·0 % wt. and pour point 30°C has been studied. The effect of various diluents viz commercial kerosene and diesel oil on paraffin deposition and viscosity temperature behaviour have been determined. Deposition data has also been quantified in the form of a regression equation. It has been observed that added solvent significantly effect the paraffin deposition and viscosity temperature behaviour.     

蜡晶形态结构对原油降凝的影响

 采用偏光显微镜观察了不同条件下蜡晶的形态变化，对蜡结晶过程中的结构、分布状态和生长规律进行了深入的研究，采用气相色谱分析了用52#、62#、80#蜡配制的模拟油中蜡的碳数分布，考察了凝点与蜡含量之间的变化规律，以及沥青质、胶质和大分子降凝剂(PPD)对模拟油降凝、降粘的影响，为改善原油流动性提供理论依据。实验结果表明，蜡晶的微观形态结构、蜡在油中的溶解性能以及降凝剂的降凝作用与模拟油中蜡的碳数分布密切相关，只有当降凝剂分子结构与油中蜡的结构匹配时，才能达到理想的降凝效果。通过实验确定了模拟油降凝时的临界蜡含量为40%（质量分数），大于该临界值后，凝点随着蜡含量的变化幅度将大大降低。     

沈阳油田高凝油集输工艺试验研究

沈阳油田为高含蜡、高凝固点的原油，原油集输十分困难。为解决此问题，先做了原油流变性试验，但原油含水率上升．流变指敷变小，稠度增大，辅送困难，通过加降凝剂试验，效果亦也不佳，无法达到工业应用的目的；进行热处理试验．可达到降粘、降凝目的，但因降低幅度不大，失去实用意义；加稀释剂试验效果较好．但掺入量较大；采用磁防蜡器经两年试验，效果虽好，但输油温度要控制在凝固点附近而不易做到。最后研制出套管伴热保温，集肤效应电伴热、自限式电热带保温扣热解堵车等四种热输油工艺技术．解决了高凝油集输的问题．创造了可观地经济效益。     

STUDIES ON THE PLOW PROPERTIES OF VACUUM GAS OIL FRACTION FROM BOMBAY HIGH CRUDE OIL IN RELATION TO ITS COMPOSITION

The vacuum gas oil fraction 375-Crude oil is highly waxy in nature associated with high pour point (48°C). Influence of various hydrocarbon constituents viz. n-alkane, aromatic and iso + cycloparaffins on the cold flow properties of this fraction was studied. Also the dependency of nature and boiling range of liquid hydrocarbon solvent matrix on the response towards cold flow properties as a function of n-alkane concentration have been determined. It is observed that the flow properties viz. pour point, plastic viscosity and yield stress in the non-Newtonian region are a result of wax liquid matrix interaction.     

THE INFLUENCE OF VINYL ACETATE CONTENT OF THE POLY(ETHYLENE-CO-VINYL ACETATE) (EVA) ADDITIVE ON THE VISCOSITY AND THE POUR POINT OF A BRAZILIAN CRUDE OIL

Petroleum companies have enhanced the offshore exploration, where the fields are located under deep water. In such cases, the low temperature of the water leads to the cooling of the oil and provokes wax deposition. Several techniques are used to reduce the problems caused by wax deposition. Polymeric additives, as ethylene-co-vinyl acetate co-polymers (EVA), are intensively used. In this work, the influence of the EVA vinyl acetate content on the viscosity and the pour point of a Brazilian crude oil was evaluated, and correlations for these properties as a function of the EVA co-polymer concentration were established. EVA copolymers were used containing 22,32,40 and 82 wt% of vinyl acetate and the tests with the crude oil were carried out using 50, 500, 1000 and 5000 ppm of EVA as additive. The results obtained from viscosity measurements showed that only below the temperature in which the wax crystals start forming the copolymer exhibited a strong influence on the oil viscosity reduction at an optimum concentration. The pour point results showed the best efficiency to EVA 32. The results obtained from both experiments showed that the viscosity and the pour point behaviors do not present good correlations to each other.     

T803B在油品中的使用性能

考查了Ｔ８０３Ｂ在大庆原油生产的中性油中的降凝效果，在多级发动机中与复剂、ＯＣＰ等的配伍性以及与其它降凝剂的复合性能。     

THE INFLUENCE OF VINYL ACETATE CONTENT OF THE POLY(ETHYLENE-CO-VINYL ACETATE) (EVA) ADDITIVE ON THE VISCOSITY AND THE POUR POINT OF A BRAZILIAN CRUDE OIL

Petroleum companies have enhanced the offshore exploration, where the fields are located under deep water. In such cases, the low temperature of the water leads to the cooling of the oil and provokes wax deposition. Several techniques are used to reduce the problems caused by wax deposition. Polymeric additives, as ethylene-co-vinyl acetate co-polymers (EVA), are intensively used. In this work, the influence of the EVA vinyl acetate content on the viscosity and the pour point of a Brazilian crude oil was evaluated, and correlations for these properties as a function of the EVA co-polymer concentration were established. EVA copolymers were used containing 22,32,40 and 82 wt% of vinyl acetate and the tests with the crude oil were carried out using 50, 500, 1000 and 5000 ppm of EVA as additive. The results obtained from viscosity measurements showed that only below the temperature in which the wax crystals start forming the copolymer exhibited a strong influence on the oil viscosity reduction at an optimum concentration. The pour point results showed the best efficiency to EVA 32. The results obtained from both experiments showed that the viscosity and the pour point behaviors do not present good correlations to each other.     

STUDIES ON THE PLOW PROPERTIES OF VACUUM GAS OIL FRACTION FROM BOMBAY HIGH CRUDE OIL IN RELATION TO ITS COMPOSITION

ABSTRACTS

The vacuum gas oil fraction 375–Crude oil is highly waxy in nature associated with high pour point (48°C). Influence of various hydrocarbon constituents viz. n-alkane, aromatic and iso + cycloparaffins on the cold flow properties of this fraction was studied. Also the dependency of nature and boiling range of liquid hydrocarbon solvent matrix on the response towards cold flow properties as a function of n-alkane concentration have been determined. It is observed that the flow properties viz. pour point, plastic viscosity and yield stress in the non-Newtonian region are a result of wax liquid matrix interaction.     

AA-MA-VA共聚物的合成及其对原油的降凝减粘作用

对丙烯酸高碳醇酯—马来酸酐—醋酸乙烯酯共聚物(AA—MA—VA)的合成方法,及其对原油降凝减粘效果进行了研究。着重考察了它对胜利—中原原油流变性能的影响。结果表明,当添加量为0.1％时,原油凝固点下降12℃,表观粘度下降60.6％(30℃),屈服值下降78.6％。说明在胜利—中原原油中加入AA—MA—VA化学降凝剂后其降凝减粘和流变性能改善效果显著。     

表面活性剂对原油流变性的作用与分子动力学模拟

选取5种合成降凝剂中常用的表面活性剂：丙烯酸、丙烯酰胺、顺丁烯二酸酐、乙酸乙烯酯和苯乙烯，采用试验和分子动力学模拟相结合的方法，考察其对原油流变性的影响。结果表明：在加剂量为2000mg/kg的条件下，5种表面活性剂的加入对原油的凝点影响较小，均使原油的凝点仅提高1℃；对原油的黏度和屈服值影响较大，其影响程度从大到小的顺序为：丙烯酰胺>丙烯酸>苯乙烯>顺丁烯二酸酐>乙酸乙烯酯；与空白原油体系相比，5种加剂原油体系势能降低，非键能负向升高，作用效果强弱顺序与试验结果相吻合，从分子层面解释了表面活性剂对原油流变性产生影响的作用机理。