Chemical Structure Effect of (Meth) Acrylic Ester Copolymers and Modified Poly (Etliylene-co-Vinyl Acetate) Copolymer on Paraffin Deposition Prevention in Crude Oil

ABSTRACT

Acrylic and methacrylic esters copolymers in various compositions: were synthesized in order to study the chemical structure effect over their effectiveness as pour point reducers in crude oil. Copolymerization results data from octadecyl methacrylate, hexadecyl methacrylate with methyl methacrylate and octadecyl acrylate, hexadecyl acrylate with methyl acrylate revealed superior results for acrylate monomers compared to methacrylate ones. Copolymers of ethylene and vinyl acetate (EVA) containing 19, 31 and 40% of vinyl acetate were chemically modified aiming to improve their performance as pour point reducer in crude oil. Ester pendant groups were introduced in the copolymer main chains resulting in meaningful increase of their performance as additive.     

原油生产中的石蜡沉积及其控制

防蜡方法按其作用原理可分为3类：（1）改善设备表面的性质;（2）增加石蜡在原油中的溶解度;（3）降低石蜡晶体的沉积性能。目前使用得最多的防蜡方法为防蜡剂防蜡法,本文主要讨论防蜡防剂防蜡法,清蜡 水基和油基两种,油基清蜡剂清蜡法的原理是将对沉积石蜡具有较强溶解和携带能力的溶剂分批或连续注入油吉的油套环形空间或集油管线内将沉积石蜡溶解并携带走。     

Experimental Investigations of the Mitigation of Paraffin Wax Deposition in Crude Oil Using Chemical Additives

Abstract

Wax deposition from crude oil is a very expensive problem for oil producers around the world. The objective of this study is to understand the characteristics of paraffin wax deposition and to test the effectiveness of solvents in the inhibition of the crystallization and subsequent precipitation of the paraffin wax and to test the most effective concentration of the solvent used. The oil used here is from the Dakota formation from the Fourteen Mile Field in the Big Horn Basin of Wyoming. Two paraffin inhibitors were tested for this crude oil on a horizontal flow system. The inhibitors are mixtures of solvents, pour point depressants, and wax crystal modifiers. These inhibitors were tested at different concentrations and temperatures and the deposition rates were obtained for each. One inhibitor especially designed for this crude oil was relatively successful, reducing the deposition by up to 59% depending on the temperature.     

不同极性的乙烯-醋酸乙烯酯共聚物对原油中沥青质分散稳定性的影响

以储罐储存的阿曼原油及不同醋酸乙烯酯基团(VA)含量的乙烯-醋酸乙烯酯共聚物(EVA)为研究对象,通过实验研究了添加EVA前后原油中沥青质的动态稳定性、离心稳定性及粒度分布的变化,进而探讨了在相同相对分子质量的情况下,VA基团含量对EVA分散稳定沥青质作用的影响。结果表明,VA基团质量分数为30%的EVA分散稳定沥青质的作用最强;EVA通过吸附于沥青质表面,抑制沥青质絮凝沉淀,从而起到分散稳定沥青质的作用;非极性基团的空间阻碍作用和EVA与沥青质间的吸附作用共同影响了EVA分散稳定沥青质的效果;增加VA含量会导致EVA中非极性链的数量和长度减小,减弱EVA非极性链的空间阻碍作用,从而减弱EVA分散稳定沥青质的效果。分子动力学模拟表明,增加VA含量会增强EVA与沥青质的吸附作用,从而提高EVA分散稳定沥青质的效果。     

原油性质对油井结蜡程度的影响

主要就原油的性质对结蜡程度的影响,以及采油井的结蜡规律进行了研究。通过实验得出结论如下:对于不同的油井,原油的含蜡量越高,在相同油井深度处结蜡蜡样的含蜡量也越高,油井结蜡越严重;对于同一口油井,随着油井深度的增加,结蜡蜡样的蜡含量、蜡样相对密度和凝点也相应增加;油井深部结蜡严重,越靠近井口结蜡越轻。     

改性乙烯醋酸乙烯酯共聚物对水泥浆性能的影响

针对水泥环脆性较高,在固井后的施工作业中其完整性易遭受破坏的问题,将用太古油改性的EVA(乙烯醋酸乙烯酯共聚物)作为增韧材料加入油井水泥中,研究了其对油井水泥浆体系常规性能和力学性能的影响,分析了其对水泥石力学特性的影响机理。结果表明,改性EVA与水泥浆的相容性较好,其对浆体的流动性、失水量影响较小,水泥浆稠化时间随改性EVA掺量增加而延长;改性EVA对水泥石抗压强度影响较小,但能提高水泥石的抗折强度和韧性,当改性EVA加量为3%时,水泥石75℃养护3 d的抗折强度提高4.4%,压折比减小28.0%,掺量为4%时,水泥石弹性模量降低39.5%。改性EVA水解产物和水泥水化产物相结合,生成的晶体和脱水聚合物使水泥石内部结构更加致密,减小或消除了水泥石内应力集中,阻止了裂缝扩展,改善了水泥石的力学特性。     

原油管道清防蜡技术研究进展及应用*

为了防止油井结蜡造成输油管道减径或堵塞影响油井生产效率,造成重大的经济损失及事故的发生,从结蜡机理、结蜡影响因素以及油管清防蜡技术等方面进行了分析综述。分析认为,不同的清防蜡技术均有其自身优点与不足,对于不同井下环境应当采用相应清防蜡技术;同时,在进行清防蜡工作前,需要对井况进行充分研究,针对井下结蜡层特点及成因结合各技术优点,选择适合的清防蜡技术工艺或多种技术结合应用;化学清蜡技术中安全环保乳液型清蜡剂是现阶段研究的热点,而清蜡与防蜡作用并举起到降凝、降黏作用的多功能清蜡剂是未来发展的方向。     

原油防蜡剂FLJ-1的合成及性能评价

针对原油集输问题中结蜡防治技术问题,以马来酸酐、丙烯酸甲酯、苯乙烯和十八醇为原料,以甲苯为溶剂,制得原油防蜡剂FLJ-1。对防蜡剂FLJ-1进行了红外光谱表征,并用青海油田原油评价了FLJ-1降低原油析蜡点的能力、结蜡量及防蜡率。结果表明,FLJ-1能有效降低原油的析蜡点,其浓度为600 mg/L时,原油的析蜡点降低了14℃;此外,FLJ-1能与原油中的石蜡分子发生吸附-共晶作用,在循环水温5℃下,其浓度为600 mg/L时,防蜡率为66.6%。     

热处理温度对长庆原油蜡沉积特性的影响

通过Couette蜡沉积装置及DSC热分析探究了热处理温度对长庆原油蜡沉积特性的影响,发现随着热处理温度的升高,长庆原油蜡沉积速率减缓,蜡沉积层老化速率加快;经50 ℃和60 ℃热处理的长庆原油,蜡沉积层出现了分层现象,其表层为流动性较强的凝油状蜡沉积层,底层为结构较为致密的类固态蜡沉积层;经70 ℃热处理的长庆原油,蜡沉积层极薄且致密,无分层现象,其表面无凝油状蜡沉积层。采用沥青质分散程度分析、DSC热分析及蜡晶形貌显微观察探究了其影响机理,发现随着热处理温度的升高,长庆原油沥青质分散程度增大,从而使其析蜡点降低,蜡晶团聚性增强,原油低温流动性得以改善,进而对其蜡沉积特性产生了显著影响。     

超临界CO_2中疏水改性聚丙烯酸的合成及其溶液性质

在水溶性单体丙烯酸(AA)与疏水性单体丙烯酸十八酯(ODA)中,加入N,N′-亚甲基双丙烯酰胺(MBAM),在超临界CO_2介质中合成了疏水改性聚丙烯酸(HMPAA)。采用扫描电子显微镜、乌氏黏度计和旋转黏度计对HMPAA的性质进行了表征,考察了温度、HMPAA溶液质量浓度、MBAM含量、HMPAA溶液pH对HMPAA溶液表观剪切黏度的影响。实验结果表明,HMPAA为白色粉末,由粒径约2μm的颗粒组成;HMPAA溶液表观剪切黏度随HMPAA溶液pH的增大先增大后降低;HMAA溶液表观剪切黏度随HMPAA溶液质量浓度的增加而增大;当MBAM的质量分数小于0.51%时,HMPAA溶液表观剪切黏度随MBAM含量的增加而增大。当HMPAA溶液质量浓度为0.8 g/dL、温度30℃、m(AA):m(ODA)=9:1、w(MBAM)=0.51%时,HMPAA溶液的表观剪切黏度达到75.0Pa·s。     

CO_2在原油中的扩散及引起的沥青质沉积

CO2在原油中扩散和溶解,使得原油体积膨胀和黏度降低的同时,原油组分也发生变化,可能引起沥青质等重有机质沉积,伤害储层,因此需全面评价CO2在原油中的扩散和影响因素以及可能引起的沥青质沉积程度。用压力降落法测定了压力和沥青质含量对CO2在原油中的扩散系数和溶解度的影响。结果表明,随着压力增加,CO2在原油中的扩散系数成线性增加,溶解度先增加后降低。随原油沥青质含量的增加,CO2扩散系数降低,溶解度增加。CO2扩散后的原油沥青质含量大幅降低,最高降幅达94.6%,表明CO2在扩散过程中引起了沥青质的沉积。     

聚苯乙烯-马来酸脂肪酰胺的合成及对高凝油结晶和流变性能的影响

以聚(苯乙烯-马来酸酐)和脂肪胺为原料,通过化学修饰的方法合成了侧链接枝脂肪酰胺的梳型共聚物聚苯乙烯-马来酸脂肪酰胺(SMAC)。利用1H NMR、DSC、流变性能测试等方法分析了SMAC的化学结构,研究了SMAC对高凝油屈服应力的影响以及SMAC对高凝油中蜡晶的相转变温度和相变焓的影响。实验结果表明,SMAC的胺化度随侧链长度的增长而降低;SMAC可有效降低高凝油的屈服应力,最高降幅可达93.2%;随SMAC的胺化度和侧链长度的增大,高凝油屈服应力的降幅增大;SMAC可有效降低高凝油中蜡晶的相转变温度和相变焓。     

乙烯-醋酸乙烯酯共聚物的功能化与应用

综述了导电功能化乙烯-醋酸乙烯酯共聚物(EVA)的电性能和力学性能,讨论了导电功能化EVA的逾渗阈值与其链组成及导电添加剂的关系,指出导电功能化EVA复合材料的电导率可达0.17 S/cm,且具有很好的力学性能和柔顺性,EVA与其他不相容的第二基体复合是提高导电添加剂分散性、降低逾渗阈值的有效途径,同时介绍了导电功能化EVA在电磁屏蔽材料、温度系数材料、电子封装材料、传感元件、固态聚合物电解质基体材料和电化学电容器的基底和集流体等电子领域的应用情况和发展前景。     

原油沥青质沉积评价方法研究进展*

原油开采过程中,因温度、压力、油相组分变化以及外来流体等因素的影响,容易破坏原油胶体体系的相平 衡状态,导致沥青质不断缔合、沉积,对原油开采及后处理带来极大的困难。综述了原油沥青质沉积评价方法, 包括滴扩散法、黏度法、光学法、电导率法、微观分析法、驱替实验法、热力学法等。对现有评价方法存在的问题 及发展趋势进行了分析,急需一种能够反映油藏条件下沥青质沉积过程的普适性评价方法,可以预测原油中沥 青质沉积的可能性,针对性优化沥青质沉积抑制技术和解堵技术。     

双亲性聚(丙烯酸-co-苯乙烯)的制备及其自组装行为

在二氧六环介质中,通过自由基溶液共聚,合成了一系列组成不同的双亲性无规共聚物聚(丙烯酸-co-苯乙烯)(P(AA-co-St)),用核磁共振、凝胶渗透色谱和示差扫描量热等方法对P(AA-co-St)的结构参数进行了表征。在选择性溶剂(二氧六环/水)中,对一系列组成不同的P(AA-co-St)进行自组装,制得粒径不同的P(AA-co-St)胶束。用紫外可见光分光光度计、激光光散射仪、扫描电子显微镜等研究了P(AA-co-St)在水溶液中的胶束化行为。实验结果表明,P(AA-co-St)在选择性溶剂(二氧六环/水)中可实现自组装,形成规则球状胶束。P(AA-co-St)中AA的含量及胶束化条件的改变对P(AA-co-St)胶束的形成、胶束流体动力学半径(Rh)和临界聚集水含量(CWC)均有影响。CWC随AA含量的增加而增大;当x(AA)<44.8%时,Rh随AA含量的增加而减小;当x(AA)>44.8%时,Rh随AA含量的增加而增大;缓冲溶液的pH从4增加到10时,Rh从170nm减至50nm。     

硬脂酸二乙醇酰胺丙烯酸单酯-马来酸酐-醋酸乙烯酯共聚物柴油降凝剂制备及评价

以硬脂酸二乙醇酰胺丙烯酸单酯、马来酸酐、醋酸乙烯酯为单体,采用溶液聚合法合成了硬脂酸二乙醇酰胺丙烯酸单酯-马来酸酐-醋酸乙烯酯降凝剂,考察了单体物质的量比、引发剂用量、聚合温度对降凝效果的影响.通过红外光谱对共聚物分子结构进行了表征,结果表明,合成的分子结构和设计目标分子结构相符.此降凝剂可使东营0#柴油的凝点降低7℃...     

Laser Based Detection of Paraffin in Crude Oil Samples: Numerical and Experimental Study

A laser spectroscope was used to detect paraffin in paraffin contaminated oil samples. After passing through the oil sample, the laser light was detected by using a semi-conductor photodiode, which in turn converts the light signal into electric voltage. The samples studied have paraffin concentrations ranging from 20-60% wt and a thickness of 1-10 mm. The results showed a good agreement with Beer Lambert's Law for the attenuation of light. A 1-D mathematical model based on energy balance and describing the process of laser radiation attenuation within the oil sample was developed and numerically solved. The model was used to predict the net laser light and the amount of light absorbed per unit volume at any point within the oil sample. The results of the numerical model were found to be in correlation with those obtained from the experiments. The mathematical model presented was then used for different types of oil products to determine the local rate of absorption in an oil layer under different working conditions. Most of the factors affecting the light absorption were considered. The effects of the angle of incidence, bottom reflectivity, and layer depth are presented and discussed.     

An Experimental Study on Wax Deposition of Water in Waxy Crude Oil Emulsions

Abstract

The key factors affecting wax deposition of water-in-oil emulsion were studied experimentally using a cold finger device. Wax deposition characteristics of emulsions were obtained. The results showed that the wax deposition profile of emulsions as a function of temperature parameters was similar to that of single oil. However, the effect of the extent of water cut on wax deposition was obviously different at different temperatures. Furthermore, the relative mass of deposit was proposed and found independent of water cut, from which wax deposition rate at different water cuts could be predicted and the predicted values were in good agreement with experimental data.     

原油化学脱硫剂的研究与应用现状

详细介绍了湿法脱硫中所用的化学脱硫剂,包括胺脱硫剂、氢氧化物脱硫剂、含醛脱硫剂、强氧化性脱硫剂和其他新型脱硫剂,分析了各种脱硫剂的组成、针对不同硫化物的作用效果及特点,指出发展方向。     

降凝剂对管输原油含蜡的处理作用

本文介绍了含蜡原油在管道输油过程中的结蜡过程,以及利用降凝剂降低含蜡原油析蜡点的机理,通过控制管道中原油的粘度达到有效地利用降凝剂的目的。