Aminated Copolymers as Flow Improvers for Super-viscous Crude Oils

The new flow improvers for super-viscous crude oils were developed via esterification of polybasic high carbon alcohol with methacrylate and copolymerizafion of monomers followed by amination of copolymers. The structure of the synthesized polymer flow improver additive was confirmed by IR spectroscopy and the crystal structure of the flow improver additives were determined by X-ray diffrac- tion analysis. The structure of wax crystals was also studied at the same time. The results showed that the wax crystal structure was closely related with the crystal structure of the flow improver, which could change the pour point depression and viscosity reduction behavior of the crude oil. When the wax crystal structure matched well with that of the additive, the wax crystals were dispersed satisfactorily, resulting in favorable effects in terms of pour point depression and viscosity reduction. The new synthe- sized aminated polymer flow improver additive was most efficient for treating super-viscous crude oils. The super-viscous crude oil had a high content of resins and asphaltenes, which might aggregate onto the surface of wax crystals to form blocks to limit the crude oil fluidity. However, amination of copolymers having similar structure with the resins and asphaltenes contained in crude oil could dissolve the huge polar groups to make the deposit formation difficult.     

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。     

STUDY ON THE MICROEMULSION BEHAVIOR OF THE OXIDIZED PARAFFIN WAX

ABSTRACT

The interfacial tension between paraffin wax and water, as well as oxidized paraffin wax and water has been studied and the results showed that the interfacial tension between oxidized paraffin wax and water decreased obviously after paraffin wax was oxidized to proper degree. Meanwhile the pseudo-ternary phase diagram of the oxidized paraffin wax/surfactants/water system has been determined. It was confirmed that using a single surfactant A or cosurfactant B couldn't prepare oxidized paraffin wax microemulsion and the cosurfactant A/surfactant B mass ratio k _m has a proper range and an optimized value to produce the oxidized paraffin wax microemulsion, moreover, the microemulsion particle distribution was analyzed.     

Effect of surfactants and their blend with silica nanoparticles on wax deposition in a Malaysian crude oil

The present study investigated the wax deposition tendencies of a light Malaysian crude oil(42.4° API), and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the wax inhibition research revolved around polymeric wax inhibitors, which cause environmental issues, we highlighted the potential of surfactants and their blend with SiO_2 nanoparticles as wax deposition inhibitors. Different surfactants including oil-based, silane-based, Gemini and bio-surfactants were considered as primary surfactants. The primary surfactants and their respective blends at a concentration of 400 ppm were screened as wax inhibitor candidates using cold finger apparatus. The screening results showed a significant influence on the paraffin inhibition efficiency on wax deposition by using 400 ppm of silane-based surfactant, which decreased the wax deposition up to 53.9% as compared to that of the untreated crude oil. The inhibition efficiency among the silane-based surfactant(highest) and bio-surfactant(lowest)revealed an appreciable difference up to 36.5%. Furthermore, the wax from the treated sample was found to deposit in a thin gel-like form, which adhered inadequately to the surface of the cold finger. A further investigation by blending the 400 ppm silane-based surfactant with a 400 ppm SiO_2 nanoparticle suspension in a load ratio of 3:1 found that the wax inhibition decreased up to 81% as compared to the scenario when they were not added. However, we have shown that the synergy between the silane-based surfactant and the nanoparticles is influenced by the concentration and load ratio of surfactant and nanoparticles, residence time, differential temperature and rotation rate.     

降凝剂对原油中蜡晶形态的影响

 摘要：采用偏光显微镜观察降凝剂(PPD) 在不同添加量下原油蜡晶形态的变化;采用图像分析软件统计分析蜡晶的数目、颗粒直径等参数,实现了蜡晶大小及其分布特征的量化描述。结果表明,随着降凝剂的加入,原油中的蜡晶由不规则的大的片状、棒状形态逐渐变成大量小的、分散较均匀的结晶形态,原先占主导地位的大直径(9～13μm)蜡晶的质量分数由67.5%下降至0.01%,小直径(2～5μm)蜡晶的质量分数由8.5%上升至95.6%;降凝剂的加入阻碍了蜡晶相互连接搭桥成网,体系能量降低,形成空间网络结构的可能性较小,原油低温流变性得到明显改善。通过非线性回归可确定降凝剂添加量、蜡晶平均直径、降凝幅度的关系,其结果与实验结果吻合。     

Pour Point Depressant of Fuel Oil Using Non-ionic Surfactants

Paraffin wax deposition from fuel oil at low temperature is one of the serious and long-standing problems in petroleum industry. The addition of pour point depressants (PPD) has been proved to be an efficient way to inhibit wax deposition. The influence of PPD on wax precipitation at low temperature was investigated. A different ethoxylated nonionic surfactants were prepared by reacting natural fatty acids (myristic acid and palmitic acid) with polyethylene glycol of different molecular weight. The synthesized nonionic surfactants were confirmed by NMR and FTIR spectroscopy. The surface properties of the synthesized surfactants, including the critical micelle concentration, effectiveness (π_CMC), maximum surface excess (Г_max), and minimum surface area (A_min) were determined. The efficiency of ethoxylated nonionic surfactants was evaluated as cloud and pour point depressant for fuel oil was discussed. The results indicate that C₁₆E₇ surfactant posse's good cloud and pour point depressing performance. The effect of additive type and compatibility additive with natural wax dispersant on the wax crystallization behavior at low (0°C) was evaluated. Photomicrographs showed that wax morphology was greatly modified to fine dispersant crystal of compact size. Correlation between wax modification and pour point depression appear to be merely qualitative in such heterogeneous fuel systems.     

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。     

水基蜡晶改进剂型防蜡剂的研制与应用

为了克服油基清防蜡剂存在的有毒、易燃、密度小等缺点,解决水基清防蜡剂存在的清蜡效率低、防蜡效果差及乳液型防蜡剂稳定性差等不足,利用表面活性剂亲水亲油基团结构特点,将蜡晶改进剂均匀地分散在水中,研究出具有低毒不易燃烧、密度较大、清蜡效率高、防蜡效果好等优点的水基蜡晶改进剂型防蜡剂。室内实验表明,该防蜡剂在最佳的配比条件下,降黏率和动态防蜡率大于70%。现场试验表明,采用连续加药方式,可有效减少洗井次数,提高油井产油量。     

Studies on the Influence of Cationic Surfactant Chemical Additives on Wax Deposition

Wax deposition studies were carried out to investigate the modification of wax crystals when gas oil was doped with some polymeric surfactant chemical additives. These additives were synthesized via esterification of chloroacetic acid and different alcohols to corresponding esters that were quaternized with polytriethanol amine and polyvinylpyridine to give polycationic surfactants. The surface activities of these polymers were evaluated using standard methods. Properties such as pour point depression data and average carbon number were studied. The behavior of the mixtures of the prepared surfactants on the depression of pour point was determined. The results given indicated that these additives are good surfactants and low temperature improvers for gas oil.     

Study on Acoustic Cavitation and Magnetic Coupling Wax Control Technology

Abstract

To solve the wax deposition problem of high-pour-point and high-waxy oil wells, a new acoustic cavitation and magnetic coupling shaft wax control technology was proposed. Experimental research and field tests were conducted. This wax control technology can achieve the purpose of freezing point depression, viscosity reduction by emulsification, and wax control through the combined effect of cavitation, acoustic vibration, and magnetic intensification. Laboratory experiments showed that after acoustic cavitation and magnetic coupling treatment, the viscosity reduction ratio of high-pour-point oil was over 25.5% at 30°C; the freezing point was decreased from 32°C to 27°C, a 15.6% reduction; the wax crystal structure of the oil samples was changed from crude, thick, and dense to fine, thin, and sparse. Field tests showed that the acoustic cavitation and magnetic coupling wax control device can significantly extend the well's wax deposit cycle by more than 30 days and reduce the wax thickness (Yumen Oilfield). Using this technology, the flushing period was extended more than two times, with a maximum up to nine times, and the normal production time was also prolonged (Zhundong Oilfield in Xinjiang). The results are useful for the popularization and application of the new shaft wax control technology for high-freezing-point and high-waxy oil wells.     

STUDY ON THE MICROEMULSION BEHAVIOR OF THE OXIDIZED PARAFFIN WAX

The interfacial tension between paraffin wax and water, as well as oxidized paraffin wax and water has been studied and the results showed that the interfacial tension between oxidized paraffin wax and water decreased obviously after paraffin wax was oxidized to proper degree. Meanwhile the pseudo-ternary phase diagram of the oxidized paraffin wax/surfactants/water system has been determined. It was confirmed that using a single surfactant A or cosurfactant B couldn't prepare oxidized paraffin wax microemulsion and the cosurfactant A/surfactant B mass ratio k_m has a proper range and an optimized value to produce the oxidized paraffin wax microemulsion, moreover, the microemulsion particle distribution was analyzed.     

Comparative Studies on Synthetic and Naturally Extracted Surfactant for Improving Rheology of Heavy Crude Oil

Effect of surfactants on rheological properties of heavy crude oil obtained from Mehsana Asset, Gujarat, India, were studied. Studies on effectiveness towards flow behavior were made using a surfactant extracted from a tropical Indian plant Madhuca longifolia (Mahua) and nonionic surfactant Brij-30 considering various contributing parameters such as temperature, concentration, and shear rate. Tests were performed at controlled shear rate. At 25°C, 2000 ppm Mahua and Brij-30 addition reduced viscosity of crude oil by 48% and 52%, respectively. Complex and viscous modulus of crude oil decreased significantly due to addition of both the surfactants. FTIR studies of crude-surfactant mixture showed remarkable decrease in concentration of viscosity enhancing groups such as alkanes, alcoholic, and acidic groups indicating the effectiveness of both the surfactants. Naturally extracted surfactant may be used as flow improver for transporting heavy crude oil.     

纳米二氧化硅改性聚丙烯酸高碳醇酯防蜡剂的制备及其防蜡机理研究

利用纳米二氧化硅(SiO2)表面带有羟基特性,通过硅烷偶联剂γ-氨丙基三乙氧基硅烷(K H550)对其表面进行有机改性后,采用溶液聚合的方法接枝聚丙烯酸二十二酯(PDM A),得到有机-无机纳米复合粒子(SiO2@PDM A).利用红外分析、热重分析、扫描电镜等对其化学结构、接枝率和表观形貌进行表征,利用偏光显微镜和差...     

Effect of organic alkali,n-alkanol,and nonionic surfactant ternary compound system on viscosity reduction of viscous crude oil

To reduce the viscosity of viscous crude oil and flow resistance, the effect of a ternary compound system including organic alkali, n-alkanol, and nonionic surfactants on viscous crude oil viscosity reduction was studied. The results showed that n-alkanol effectively reduced the droplet size of an emulsion and the viscosity of viscous crude oil and improved the fluidity of viscous crude oil. Of the low-carbon n-alkanols, n-pentanol has the best viscosity-reducing effect. The organic alkali avoids the phenomenon of fouling and corrosion caused by inorganic alkali and reacts with the acidic macromolecular components in viscous crude oil to generate alkanolamides, which produce synergistic effects with nonionic surfactants and reduce the interfacial tension between oil and water. In the ternary compound of organic alkali, n-alkanol, and nonionic surfactant, the viscosity reduction effect of viscous crude oil is significantly enhanced compared with that of a single reagent. The viscosity reduction rate of viscous crude oil of the diethanolamine ternary compound system reached 98.1% and was the best choice by experimental validation. It is shown that a reasonable formula of compound system and dosage can significantly reduce the viscosity of viscous crude oil.     

Characterization of ternary compound viscosity reducer system on viscosity of viscous crude oil

Based on the theory that viscous crude oil can form stable two-phase oil-water interfacial molecular membrane with surfactant, the oil-water interfacial activity and viscosity reduction of oil-water interface of viscous crude oil were studied for the ternary compound system, including anionic surfactant alpha olefin sulfonate (AOS), weak alkali Na₂CO₃ and four different kinds of nonionic surfactant emulsifying silicon oil (LKR-1023), lauryl diethanolamide (LDEA), isomeric alcohol ethoxylates (E-1306), and polyoxyethylene sorbitan monooleate (T-80). Results showed when lipophilic or hydrophilic nonionic surfactants were used separately in the same compound system. The viscosity of viscous crude oil could be reduced, but the viscosity reduction efficacy was not desirable. However, using LKR-1023, E-1306, and T-80 as nonionic surfactant with mass fraction 1.0%, the viscosity reduction rate of viscous crude oil reaches 98.92%, 98.29%, and 96.87%, respectively. With 1.4% of LDEA, the viscosity reduction rate of viscous crude oil can reach 98.89%. Through all different kinds of the nonionic surfactant tested, oil-in-water (O/W) emulsion under LDEA ternary compound system has been proved to be the most stable with no phase inversion. Therefore, it is promising to improve the viscosity reduction of the super viscous crude oil by selecting the proper surfactant and dosage.     

Non-isothermal crystallization kinetics of waxy crude oil

The crystallization behavior of Shengli waxy crude oil from the sol state to gel state was studied by the microscopic observation and DSC curve. The study shows that as the cooling rate decreases, the number of wax grains becomes smaller, the area is larger and the morphology of wax crystals is more irregular. Moreover, under different cooling rates, wax crystals were homogeneous transient nucleation, but the growth mode of wax crystals was different. When the cooling rate is between 1–4?°C/min, Crystallization Peak 1 wax crystal grows according to the mixed crystal mode of one-dimensional rod crystal and two-dimensional discoid crystal; When the cooling rate is between 6–8?°C/min, Crystallization Peak 1 wax crystal grows according to the mixed crystal mode of two dimensional discoid crystal and three-dimensional spherical crystal; Crystallization Peak 2 wax crystal grows according to the mixed crystal mode of two dimensional discoid crystal and three-dimensional spherical crystal at different cooling rates. Crystallization activation energy of crystallization Peak 1 and Peak 2 are 556.91?kJ/mol and 299.62?kJ/mol, respectively.     

物理法防蜡防垢降粘增油器的研究与应用

物理法防蜡防垢降粘增油器由射流发生器、声波振荡器、涡流导流槽、涡流导流阀和涡流喷射器5个部分组成,是集蜗流、射流、声波振荡技术为一体的新产品。它直接用于油井采油生产,其独特的设计结构能够使原油的流速、流态、温度、压力、粘度、气液相溶解度、固液相混合度、晶体析出温度及吸附生长环境、烃类组元的微观结构及其组分比等发生一系列物理变化,从而起到防蜡、防垢、降粘增油的作用。延长油矿10口井的现场应用表明,单井年创经济效益约20·25万元。     

甲基丙烯酸十八酯-顺丁烯二酸酐-醋酸乙烯酯-苯乙烯降凝剂对原油蜡晶形态的影响

用偏光显微镜(PLM)观察甲基丙烯酸十八酯-顺丁烯二酸酐-醋酸乙烯酯-苯乙烯(OMVS)降凝剂添加量对原油蜡晶形态的影响。实验结果表明,随OMVS降凝剂添加量的增加,蜡晶由不规则的棒状和片状逐渐变为粒径小、分散均匀的近似球状的蜡晶;PLM表征结果显示,加入OMVS降凝剂的非洲原油和国产原油的蜡晶颗粒数均由不到100个增至大于1300个和1700个,原先占主导地位的表面积较大(非洲原油150～250μm2和国产原油100～200μm2)的蜡晶个数由超过60%降至1%以内,表面积较小(5～50μm2)的蜡晶个数由不到10%增至90%以上。通过指数回归可确定OMVS降凝剂添加量-蜡晶平均表面积-降凝幅度的内在关系,计算结果与实验结果吻合。     

防蜡剂SZ－3及其性能特点

为了解决胜利桩西油田高含蜡原油开采中的严重结蜡问题，研制了ＳＺ－３防蜡剂。该剂为以ＥＶＡ甲苯溶液为内相，水为外相，含有油溶性和水溶性非离子表面活性剂和低分子醇的Ｏ／Ｗ乳状液，从油套环空投入采油井井底，防蜡效果良好。本文介绍了该剂的研制、配方、室内性能测定和现场试验简况。     

Cold flow properties and crystal morphologies of biodiesel blends

A soybean biodiesel was prepared and blended with a conventional China’s No. 0 petrodiesel. The pour points (PP) and cold filter plugging points (CFPP) of the biodiesel blends were evaluated on a low-temperature flow tester. Dynamic viscosities of the blends at different temperatures and different shear rates were measured on a rotatory rheometer. The crystal morphologies of the biodiesel blends at low temperatures were analyzed using a polarizing microscope. The results indicate that the blended fuels provided a slight decrease in PPs and CFPPs as compared with those of neat soybean biodiesel and pure petrodiesel. Below the temperatures of PPs or CFPPs, the dynamic viscosity of the biodiesel blends increased dramatically with decreasing temperature, but decreased with increasing shear rate, the biodiesel blends exhibiting non-Newtonian behavior. At temperatures higher than PPs or CFPPs, linear relationships appeared between dynamic viscosity and shear rate and the biodiesel blends became Newtonians. At low temperatures, wax crystals of the biodiesel blends grew and agglomerated rapidly. The loss of fluidity at low temperatures for the biodiesel blends can therefore be attributed, on the one hand, to the sharp increase of viscosity and, on the other hand, to the rapid growth and agglomeration of wax crystals.