Synthesis of cyclohexanone-alcohol hemiketals and evaluation as flow improver for waxy crude oil

In this paper, four novel cyclohexanone-alcohol hemiketals (KL-1, KL-2, KL-3, KL-4) as waxy crude oil flow improver have been prepared by cyclohexanone and 1-pentanol, 1-Hexanol, 1-heptanol, 1-octanol. Evaluation results demonstrate the hemiketal compounds have obvious effect on the viscosity and pour point of Henan crude oil. DSC analysis showed that waxing point and waxing peak decreased to a certain degree in 0.05% hemiketal solutions. Wax crystal morphology analysis indicated the four hemiketals played a role of nucleation in the process of waxy crude oil decoagulation, and in that way acts as waxy crude oil flow improver.     

Some biosurfactants used as pour point depressant for waxy egyptian crude oil

Two bacteria (B1 and B2) were isolated from soil-contaminated sites. The surface properties of biosurfactants produced by these bacteria were determined. These bacteria were given a good resistance to NaCl concentration up to 20%. The surface activity was detected with maximum value at pH7 with B1, whereas B2 was not affected by the change pH (3–12). The biosurfactants of these bacteria were added as a mixture or individual to crude oil given the good result in reducing the pour point. The infrared spectrum of wax or asphaltene fractions of Egyptian crude oil untreated and treated with biosurfactants was detected.     

国内原油降凝剂研究概况

介绍了目前我国原油降凝剂应用现状、研究成果和应用的种类,综述了降凝剂的工作机理,并对今后研究提出了建议:加强降凝剂机理研究,开发适用范围更大的新型降凝剂,研究低温降凝剂,降凝剂研究应与输油工艺紧结合等。     

Hexa-triethanolamine oleate esters as pour point depressant for waxy crude oils

New crystal modifier surfactants were developed by esterification of hexa-triethanolamine with oleic acid to prepare mono, di, and tri-esters. The synthesized esters were confirmed by IR spectroscopy and the molecular weight of the major compound in the reaction mixture was determined by MS analysis. Surface properties of the synthesized modifiers, including critical micelle concentration (CMC), effectiveness (π_cmc), maximum surface excess (Ί_max) and minimum surface area (A_min) were determined at 30 °C. The synthesized esters were evaluated as flow improver (FI) and pour point depressant (PPD). Hexa-triethanolamine mono-oleate was most efficient for crude oil (I), and hexa-triethanolamine tri−oleate was most efficient for crude oil (II).     

锦州高含蜡原油降凝剂的筛选及现场应用

锦州原油高含蜡量高,凝点普遍在20℃以上,低温流动性差。为了保证冬季的安全输送,对实验室内开发研制的G5系列降凝剂进行了筛选,得到降凝效果最好的G51,并对影响其降凝效果因素进行了分析研究。实验结果表明,最佳加剂温度为60℃,合理的加剂浓度为400mg／L,可使原油的凝点由原来的22℃降至13℃,并且降凝剂具有良好的静态稳定性和配伍性,能保证管道的安全运行。     

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...     

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。     

热处理作用对含蜡原油流变性的影响

热处理技术是改善含蜡原油低温流动性的一种主要方法,以BH油田含蜡原油为例,通过一系列热处理试验对含蜡原油进行了流变性能研究,对实验数据进行了理论分析,并结合现场应用情况验证了试验结论的正确性。分析结果表明：温度是影响热处理效果的主要因素,中温段（50～60℃）的热处理会对含蜡原油的凝点产生恶化效果;高温段（70～95℃）的热处理可以大幅降低含蜡原油的凝点。冷却速度对含蜡原油热处理效果的影响至关重要,当冷却速度较小（0．5～1．0℃／min）时,油样热处理效果较好;冷却速度太快（1．2～1．5％／min）,将使热处理效果变差。剪切速率对热处理效果有一定影响,通常在较低速率的剪切作用下,原油热处理效果较好,随着剪切速率的增加,原油热处理效果变差。热处理后油样的稳定性对热处理效果的影响也不可忽视。     

Application of bayesian regularized artificial neural networks to predict pour point of crude oil treated by pour point depressant

The pour point of the crude oil treated with the pour point depressant (PPD) is easily affected by the shear history effect. Models for pour point of PPD-treatment crude oil affected by the shear history effect based on Bayesian regularized artificial neural network (BRANN) were established. The results showed that BRANN models not only had a good ability of fitting to the training data, but also had a good ability of predicting the testing data. By evaluating network performance with several statistical indicators, the three models have excellent performance, high accuracy, and strong generalization ability. The influence of each parameter on the pour point were also investigated through a sensitivity analysis, which shows that the entropy generation due to viscous flow is the most important parameter in predicting the pour point.     

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.     

剪切作用与加剂原油粘度关系的数学模型

分析了剪切作用对加剂大庆原油粘度的影响规律,建立了剪切后加剂原油粘度与剪切过程中粘性流动熵产关系的数学模型.根据剪切效应的一般规律及机理,提出了近似确定模型中参数的简易方法.按照此方法,只须测定一定温度下空白原油的粘度或表观粘度、未剪切时加剂原油的粘度或表观粘度,及在某一个剪切温度下及某一个粘性流动熵产条件下原油的粘度或表观粘度,即可近似确定该数学模型中的参数,从而预测在不同温度时剪切后的原油在该温度下的粘度或表观粘度.结合含蜡原油粘度与温度关系机理模型,还可以预测同一加剂原油经受剪切后在其他温度下的粘度.对中原原油和加剂轮南丘陵混合原油加剂试验数据的验证结果表明,该模型有较好的预测准确性.     

原油流动改进剂降低转相点的实验研究

为减小原油在集输过程中的流动阻力,在实验室进行了向含水原油中加入DODE系列流动改进剂后的原油流动性实验.结果表明,含水原油中添加DODE系列流动改进剂可以使含水原油的转相点由原来的50％ ～70％提前到了30％ ～50％,形成具有适度稳定性的水包油型原油乳状液,有效降低了原油乳状液的表观粘度.     

Transportation technology with pour point depressant and wax deposition in a crude oil pipeline

The authors systematically studied transportation technology with pour point depressant and wax deposition in an industrial crude oil pipeline. Experiment results manifest that beneficiated oil acquires obvious modification effect and the reheating temperature of intermediate heat stations should be above 55°C to avoid effect deterioration. Heating schemes are made with lower heating temperature and wider output range. Moreover, an applicable wax deposition model is established to predict wax deposition distribution along the pipeline under various operating conditions. Wax deposition rate varies severely along the pipeline and it is necessary to consider its non-uniformity in production.     

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%。     

Synthesis of new flow improvers from canola oil and application to waxy crude oil

Several techniques are employed to mitigate the problems associated with the crystallization of paraffin during the production and/or transportation of waxy crude oil. One of these techniques is the addition of chemicals that depress the pour point of the oil and inhibit the formation of paraffin crystals. In this work, the chemicals, polyamine amide (PAA), are prepared by aminolysis and polycondensation from canola oil and polyamine as substrates. Nitrogen atoms are fixed in the main chain of the polymers to modify the polarity. The effectiveness of the PAAs on four crude oil was tested as pour point depressants as well as paraffin inhibiters. The highest pour point reduction depression was achieved as 12.6°C. Differential scanning calorimetry and paraffin crystal morphology studies were conducted on simulated crude oil to elucidate the mechanism of pour point reduction.     

储层条件下的含蜡原油流变性研究

为研究含蜡原油在储层条件下的流变性,应用高压拈度计,在储层压力条件下开展了原油流变性实验。结果表明：在较低的温度条件下,含蜡原油的拈度随剪切速率增大而减小,且起初在一定的剪切速率范围内减幅较大,随后减幅越来越小;随着温度的降低,含蜡原油的表观拈度、拈流活化能及稠度系数增大,非牛顿指数减小,流变特性越来越偏离牛顿流体;采用非牛顿指数、稠度系数、拈流活化能和结构拈度指数等4项参数,能较全面地表征储层条件下含蜡原油的流变性。     

Advances in rheology and flow assurance studies of waxy crude

Flow assurance is one of the core issues in safe and economical operation of waxy crude pipelines.Its essence lies in flow and heat transfer of the crude.In the past 10 years,the authors’ team has achieved a lot of innovative results in aspects of waxy crude rheology,flow assurance assessment,and pipelining technologies on the basis of decades of studies.The rheological characteristics of waxy crude are much better understood,and a method for quantitatively simulating the effect of flow shear was developed based on some theoretical breakthroughs.Studies of the mechanism of waxy crude rheology have been deepened to the quantitative level.After successful development of efficient numericalalgorithms,accurate simulations have been achieved for various complex flow and heat transfer situations in waxy crude pipelining,and a reliability-based approach to flow assurance assessment has been set up.New pipelining technologies have been developed such as batching pour-point depressant-(PPD-) treated multiple-waxy-crudes,intermittent transport of waxy crudes through long-distance pipelines,and batching hot and cold crudes.By their application,a series of problems hindering safe,efficient and flexible operation of waxy crude pipelines were tackled,demonstrating that transportation technologies for waxy crude have advanced to a new and high level.     

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。     

Effect of drag reducer and pour point depressant on the wax deposition of crude oil pipeline

In this paper, the data of wax precipitation before and after the addition of the additives showed that the addition of the drag reducing agent (DRA) and the pour point depressant (PPD) cannot change the wax appearance temperature (WAT) of crude oil. When the dosage of DRA is small, the DRA cannot increase, stop, or slow down the precipitation of wax crystals. The addition of PPDs has no influence on the amount of precipitated wax crystals. From the GPC analysis, the molecular weight of the wax deposit samples in Linpu pipeline is from 500 to 76,800, which indicates that there is no enrichment of DRA in wax deposit samples. The results of IR show that the C?O group was not detected in the wax deposit sample of the Wei Jing pipeline, which indicates that there is no enrichment of the PPDs in wax deposit samples. The results showed that the DRA and PPD have no obvious effect on crude oil pipeline wax deposition.