Wax deposition during production of waxy crude oil and its remediation

In the current paper, fundamental aspects of wax deposition problems in pipeline are defined, and characterization of paraffin and their solubility tendencies have been discussed. Wax deposition depends on flow rate, the temperature differential between crude and pipe surface, the cooling rate, and surface properties. The physico-chemical characterization of crude oil is determined. The experiments were carried out in “Cold Finger Apparatus.” Best pour point depressant for the selected crude oil has been found out as Lubrizol-6682 among different chemicals available that reduces the pour point from 36° to 12°. The deposition of paraffin wax, its dispersion, and inhibition were studied with available chemicals and by the optimization of suitable additives for particular well. Kinetics of crude oil in terms of time and differential temperature has also been studied and effective dispersion times are observed for particular oil. It is found that dispersion is effective within 30–60 min of starting. Kinetic study of oil with respect to differential temperature is done in two ways either by varying ambient/surface temperature or pumping/reservoir temperature. The tendencies of wax deposition on different sample with neat and treated crude are observed and ideal differential temperature for particular oil to flow is determined.     

Poly(ethylene-co-vinyl acetate) (EVA) as wax inhibitor of a Brazilian crude oil: oil viscosity, pour point and phase behavior of organic solutions

Several techniques have been used to minimize the problems caused by the wax deposition, and the continuous addition of polymeric inhibitors is considered an attractive technological alternative. The addition of copolymers like polyacrylates, polymethacrylates or poly(ethylene-co-vinyl acetate) (EVA) permit to inhibit the deposition phenomenon; nonetheless, this effect is specific, i.e. similar copolymers present different performance depending on their physical–chemical properties in solution. In this work, the influence of the EVA vinyl acetate content on the viscosity and the pour point of a Brazilian crude oil were evaluated. A correlation between both results was also obtained. The phase behavior and the solubility parameter of EVA copolymers, with different vinyl acetate contents, were investigated in various solvents together with an evaluation of the efficiency of these copolymers as pour point depressants for two different samples of crude oil. EVA copolymers containing 20, 30, 40 and 80 wt.% of vinyl acetate were used and 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 at which wax crystals start forming did the copolymer exhibit a strong influence in the reduction of oil viscosity, at an optimum concentration. The pour point results revealed EVA 30 to be the most efficient. The results obtained from both experiments showed that the viscosity and the pour point behaviors do not show good correlation. Not only the solubility parameter and the vinyl acetate content, but also the molecular weight and polydispersity have an important influence on both phase behavior and pour point depression. Furthermore, it was confirmed that the additive must present a reduced solubility at a temperature close to the crude oil cloud point. This, however, is not the only factor that determines the efficiency of the additive as paraffin/wax deposition inhibitor.     

Synthesis of pour point depressant for heavy oil from waste organic glass

Polymethyl methacrylate (PMMA) is widely used as a substitute for glass, known as organic glass. During the processing and after use, there are amount of castoff. Based on the similar framework, PMMA could be useful feed stock to synthesis poly methacrylamide (PMAA) used for crude oil additive. In this work PMAA was prepared by aminolysis reaction of PMMA and aliphatic amines. The performance of PMAA on heavy oil was evaluated as pour point depressant as well as paraffin inhibiter. The highest pour point reduction depression was achieved as 12.1°С with the dosage of 600 ppm PMAA 1. Differential scanning calorimetry and paraffin crystal morphology studies were conducted to elucidate the mechanism of pour point reduction.     

丙烯酸十八酯-苯乙烯共聚物对含蜡原油改性效果与分子动力学模拟

合成了单体配比不同的丙烯酸十八酯-苯乙烯共聚物(OAS)降凝剂,采用实验与分子动力学模拟相结合的方法对降凝剂的性能进行评价.实验结果表明,OAS降凝剂的降凝减黏性能随丙烯酸十八酯比例的增加呈现出先增大后减小的趋势.在2000 mg/kg加剂量下,苯乙烯与丙烯酸十八酯摩尔比为1:3的降凝剂OAS-4能使含蜡原油凝点降低4...     

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。     

新型稠油流动性改进剂制备与评价

以脂肪酸和多胺为原料,制备了聚氨酰胺,将其作为稠油流动性改进剂评价了其对稠油凝点和粘度的影响。结果表明,所合成的聚氨酰胺型稠油流动性改进剂有一定的降凝作用,最高达4.1℃。所合成的聚氨酰胺型稠油流动性改进剂中胺的种类与结构对稠油的降粘效果影响较大,脂肪酸的种类与结构对稠油降粘效果影响小。聚氨酰胺分子中主链含氮数少时侧短链烷基结构的作用效果略好于侧长链烷基结构,然而,随着主链含氮数增多时侧长链烷基结构对稠油降粘效果增加。主链含氮原子数少且侧短烷基链的聚氨酰胺的降粘效果最高达23.1%。     

肇州201区块油基清防蜡剂的研究

针对大庆肇州201区块原油含蜡量高,凝点高,易结蜡的特点,研制出了效果较好的油基清防蜡剂,确定了最佳配方,并且考察了防蜡剂加量对防蜡率和降凝效果的影响。结果表明,对A油样,1^#防蜡剂加量为1．0％时,其防蜡率可达88．6％,凝点可降低7℃;对B油样,4^#防蜡剂具有较好的防蜡降凝效果。     

聚醚酰胺的合成及其对原油流动性的影响

以聚醚酰胺和脂肪酸为原料合成了系列脂肪酸聚醚酰胺降凝剂,利用FTIR、黏度测试、界面张力测试等方法考察了降凝剂对不同原油流动性的影响.实验结果表明,该系列降凝剂具有较好的表面活性和界面活性.随碳数的增加,饱和脂肪酸聚醚酰胺降凝剂降低表面张力的能力增强.加入0.3％(w)和0.9％(w)的棕榈酸聚醚酰胺降凝剂时,风城原油...     

原油降凝剂的研制与初步应用试验

合成了两个系列的原油降凝剂 ,一个是丙烯酸高碳醇酯和马来酸酐共聚 ,然后用高级脂肪胺胺解 ;另一个是 α 烯烃和马来酸酐共聚 ,然后用高级脂肪胺胺解。添加 1 0 0× 1 0 - 6的此类降凝剂于大庆原油中 ,结合热处理 ,可降低凝固点 1 9～ 2 2℃。讨论了原油的性质、降凝剂的结构及试验条件对降凝效果的影响。加入 1 0 0×1 0 - 6试样到辽河、任丘、新疆、和大庆原油中 ,也有较好的降凝作用 ,表明这些共聚物是适合于高蜡原油的降凝剂     

苏丹三七区块原油降凝降粘技术研究

苏丹三七区块原油属于高蜡、高粘原油,原油中的蜡含量、碳原子分布和组成、胶质和沥青质均影响降凝剂的降凝效果。为了确保苏丹长输管线的安全输送,根据原油的油品性质及其分析结果,筛选出了一种对苏丹原油具有良好改性效果的原油降凝剂SL2。试验研究结果表明,在混合油中加入SL2复合降凝降粘剂1000mg/L,可使原油凝固点由40℃降至30℃,温度在50℃时,降粘率大于30%,使原油低温流动性明显改善。     

高凝原油降凝剂的合成及复配性能研究

根据高凝原油组成以及降凝剂对原油的感受性确定了合成降凝剂的高碳醇的碳数,以丙烯酸和C18～C22混合醇为原料,合成丙烯酸高碳醇酯,得到三种聚合物:丙烯酸酯自聚物(AM),丙烯酸酯-醋酸乙烯酯(AMV)和丙烯酸酯-醋酸乙烯酯-苯乙烯(AVS)。比较了三种聚合物的降凝效果,选出AVS考察其合成条件并且与常用降凝剂EVA进行复配。实验结果表明:丙烯酸酯、醋酸乙烯酯、苯乙烯最佳配比为1∶1∶0.5,引发剂用量为1.2%,单体质量浓度30%,反应时间为7h时,三元共聚物AVS与EVA的复配物CPR可以使魏岗原油凝固点降低10℃,防蜡率达到40.62%。     

管输原油降凝剂的研究进展

总结了石蜡结晶机理及其影响因素,并对国内外含蜡原油降凝剂的发展过程、作用机理、常用降凝剂的种类以及影响降凝剂作用效果的各种因素进行了介绍;指出了降凝剂在研究和应用中存在的问题,对降凝技术的发展进行了客观评价和展望。     

尿素脱蜡生产L-AN15号全损耗系统用油基础油研究

以江苏原油常三线油为原料,采用异丙醇尿素脱蜡工艺,常温常压下,尿素与正构烷烃络合形成不溶于油的络合物,使其正构烷烃从油中分出.脱蜡油经精制后粘度、倾点和闪点符合L-AN15号全损耗系统用油指标要求.蜡中正构烷烃含量近90%.     

树枝状长链酯的合成及其作为原油流动改性剂性能研究

以低代树状聚酰胺-胺和系列丙烯酸长链酯为原料,通过分子设计合成了6种具有树状结构的原油流动改性剂。采用傅里叶红外光谱、核磁共振氢谱和元素分析对其结构进行了表征,并研究了系列树枝状长链酯对原油流动性能的影响,主要分析了树状长链酯对原油凝点和流变性能的影响。结果表明,树枝状长链酯对原油流动性的影响不仅与其端基烷基链长度有关,而且与其代数也有关。端基烷基链越长,添加树状长链酯原油体系的凝点和表观粘度降低的越明显;含有8 个支化长链的1.5代树状长链酯对降低原油凝点和表观粘度的效率高于含有4个支化长链的0.5代树枝状长链酯。相同条件下,添加1.5代树状十八酯原油体系的原油凝点和表观粘度高于添加其它1.5代树枝状长链酯的原油体系。     

江苏油田B1断块原油降凝剂研究

江苏油田B1断块原油属于高含蜡、高胶质、高沥青质原油,具有高凝、高黏特点,平均凝固点41.5℃、析蜡点59～60℃,温度敏感性强。针对该区块原油特性,开展井筒降凝、降黏工艺和配方研究,进行了降凝降黏剂的评价和配比,优选了合成的复配型降凝剂KD-50（Ⅳ）,确定合理添加浓度,考察在不同温度下对B1断块原油的降黏效果。室内实验结果表明：添加降凝降黏剂后,低温流动性明显改善,凝点、反常点和低温表观黏度均有较大幅度降低,在40℃加剂后的降凝降黏率达80%以上,具有较好的推广应用价值。     

潍北高凝点原油降凝降黏剂的研制

实验室自制的三元共聚物AMV-22与EVA复配,添加SLA-107作助剂,制备适用于胜利油田潍北区块高凝点原油的降凝剂AMVES。实验考察了该降凝剂对原油的降凝降黏效果。DSC热分析结果表明,AMVES加量为1000 mg/L时,可使原油凝点从48℃降低到37℃,析蜡点降低2℃。流变性曲线表明原油的剪切稀释作用随温度升高显著增强,当剪切速率大于100 s^-1后黏度基本不变,降凝剂可以大幅降低启动原油的屈服应力。偏光显微镜图显示原油温度越低,蜡晶网状结构越致密,交联度强,黏度大,流动性差;加AMVES之后原油中蜡晶变为团簇状颗粒,原油的流动性增强。由此可见降凝剂AMVES作用于蜡晶使其三维网状结构破坏,从而有效降低原油凝点和黏度。     

Nano-composite pour point depressants in improving the rheology of waxy crude oil

This article mainly describes the advantages of nano-pour point depressants on the low-temperature fluidity of crude oil compared with traditional pour point depressants. The common nano-pour point depressants are mainly divided blend type and polymerization type. It can effectively improve wax crystal structure and strength, thereby improving the low-temperature fluidity of crude oil. Nano-particles have better application prospects in improving rheological properties of waxy crude oil.     

梳型共聚物的相对分子质量调控及其对JENM原油 的降凝效果*

为降低高蜡型JENM原油的输送成本,合成了丙烯酸十八酯-丙烯酸二十二酯-马来酸酐梳型共聚物降凝剂,考察了降凝剂相对分子质量对降凝效果的影响,并通过优化反应条件实现对聚合物相对分子质量的调控,研究了加剂前后JENM原油的析蜡特性和蜡晶形貌的变化。研究表明,随着反应温度升高和反应溶剂用量增加,降凝剂的平均相对分子质量减小;随着引发剂用量的增加,降凝剂的平均相对分子质量先增大后减小。丙烯酸十八酯-丙烯酸二十二酯-马来酸酐降凝剂的平均相对分子质量约为14000时对JENM原油的降凝效果较好,典型优化合成条件为:反应温度100℃、溶剂用量77%、引发剂用量为单体质量的1%,合成的降凝剂加剂量为0.3%时,JENM原油凝点由30℃降至17℃,降幅为13℃;30℃时黏度由9.12 Pa·s降至2.24 Pa·s,降黏率为75%,显著改善了JENM原油的低温流动性。结合DSC和显微分析发现,降凝剂的加入使JENM原油析蜡点和析蜡峰温降低,凝点处析蜡量增加。降凝剂的极性基团抑制了蜡晶生长,促进了蜡分子的分散,使晶种在更低温度才开始析出。同时,由于蜡晶更加细小,析蜡量较大时才使原油失去流动性,从而有效降低了原油凝点。图11表2参18。     

Dependence of efficiency of polyalkyl acrylate-based pour point depressants on composition of crude oil

Thirteen polyalkyl acrylate-based depressor additives with C16-C26 alkyl groups containing 0–30 mol% of various polar groups (amide, amine, ammonium, N-vinylpyrrolidone, oligo(ethylene glycol)) have been synthesized and tested in 18 crude oil samples of significantly different compositions. It has been shown that the dependences of the depressor effect on the additive concentration pass through maxima. An approach that predicts the degree of decrease in pour point of oil in the presence of polyalkyl acrylate additives depending on the content of paraffin and resin-asphaltene components was proposed for the first time. A polyalkyl acrylate with C16-20 alkyl groups proved to be the most versatile additive. However, polymers with different lengths of alkyl groups or containing polar groups are more effective for some oils.     

新型胺解原油降凝剂PSMA的合成与性能评价

采用分散聚合法以聚乙烯吡咯烷酮(PVP)为分散剂,无水乙醇为分散介质,合成了马来酸酐和甲基丙烯酸十八酯为单体的二元共聚物(PSMA-a),并对聚合物用苯胺进行酰胺化处理,得到降凝剂PSMA。采用傅里叶红外光谱和热失重对聚合物的结构和热稳定性进行表征。以大庆油田原油为实验对象,采用差示扫描热分析、石油凝点试验仪和石油产品运动黏度计对其进行了降凝降黏性能的研究。通过正交试验确定了最佳的单体配比、反应温度、反应时间和引发剂用量。实验表明,当降凝剂质量浓度为750mg/L,PVP用量为单体总质量分数的8%时,具有最佳的降凝降黏效果。