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。     

Effective flow improving agents for waxy crude oil

The comb-like copolymer-polyhedral oligomeric silsesquioxane (POSS) nano-composite PPDs, including POA-POSS, POA-VA-POSS, POA-MA-POSS and POA-St-POSS, were first synthesized via in-situ reversible addition-fragmentation chain transfer (RAFT) polymerization and characterized by FT-IR, NMR and TGA methods. Subsequently, the effects of the nanocomposite PPDs on rheology of a waxy crude oil were studied. Results showed that POA-VA-POSS is the most efficient PPD among the nanocomposite PPDs, which can depress the pour point, gelation point, apparent viscosity and yield stress of the crude oil to the lowest. Associated with the microstructure of crude oil, the rheo-logical improving mechanisms of the copolymer-POSS nanocomposite PPDs are discussed.     

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。     

The use of bio-diesel based additive as rheology improver and pour point depressant of Nigerian waxy crude

The chemical method has proved to be the most effective mitigating method of wax deposition in petroleum system as it deals with the root cause of wax formation. Most of the commercial chemicals in the industry are very expensive and toxic. This paper aims the use of biodiesel based additives for improving the rheological behavior and pour points of waxy crude from Nigeria field. The biodiesels derived additives gave better performance than the commercial chemical and the seed oils as greatly improvement in rheology and pour point values of the waxy crude were observed     

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.     

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.     

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.     

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%。     

Styrene-maleic anhydride copolymer esters as flow improvers of waxy crude oil

Four comb-like copolymers derived from styrene-maleic anhydride copolymer were prepared and characterized by FTIR, ¹H-NMR and elemental analysis. The molecular weight was determined using GPC and their intrinsic viscosity was measured. The prepared polymers were investigated as pour point depressants and flow improvers for waxy crude oil and it was found that, the maximum depression was obtained by the sample that has long branch chain (PPD4) from 27 °C to − 3 °C (ΔPP = 30 °C, at 10,000 ppm), while the minimum depression was exhibited by short branch chain, PPD1 (ΔPP = 21 °C) at the same conditions.The effect of these polymers on the rheology and flow properties of Qarun waxy crude oil was investigated. It was found that the Bingham yield value (τ_β) decreased from 6.0 Pa s to 0.5 Pa s for PPD4 at 27 °C and 10,000 ppm. The dynamic viscosity also decreased from 110 mPa s to 24 mPa s for the same sample and the same conditions.     

江汉原油降凝剂的制备及其性能研究

利用溶液聚合反应合成了一系列丙烯酸酯类高蜡原油降凝剂,并对其降凝效果进行研究。研究结果表明：采用摩尔配比为6：3：1的丙烯酸十八酯,马来酸酐和醋酸乙烯酯组成的混合单体制备的三元聚合物高蜡原油降凝剂MVA-3对江汉原油具有明显的降凝效果,在加剂量为1000mg／kg时,可以使江汉原油的凝点降低12℃。高蜡原油降凝剂MVA-3能够同原油中的胶质和沥青质有效结合,可以降低原油中固有的胶质一沥青质聚集体在原油中的析出温度,改变原油中蜡的结晶方式,降低蜡结晶析出温度和蜡结晶析出速度,并能减少原油中蜡的析出总量。     

Synthesis and characterization of N-alkyl-2-aminopyridinum oligomers as pour point depressants for crude oil

The synthesis of N-decyl- (C10P), N-dodecyl- (C12P) and N-cetyl-2-aminopyridinum (C16P) oligomers was achieved by oxidative polymerization of N-decyl- (C₁₀), N-dodecyl- (C₁₂) and N-cetyl-2-aminopyridinium bromide monomers respectively in aqueous acid medium. Density function theory (DFT) was applied to recognize the reactive center in monomers used. The result of quantum calculations indicated that the oligomerization could proceed via open ring reaction. The obtained oligomers were characterized using FTIR and ¹H NMR spectroscopy. In addition, the XRD and SEM were used to investigate the morphology of the prepared oligomers. The thermal stability of the obtained oligomers was followed by thermogravimetric analysis (TGA). The conversion of these oligomers is ranged from 61 to 68% and the weight average molecular weights are closed to 3000?g?mol^?1. The surface tension of the synthesized oligomers was measured at different concentrations and temperatures. The efficiency of the synthesized oligomers in depressing the pour point of crude oil was investigated. The synthesized oligomers showed high efficiency as pour point dispersants.     

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.     

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.     

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。     

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。     

Synthesis of phthalimide and succinimide copolymers and their evaluation as flow improvers for an Egyptian waxy crude oil

This paper describes the synthesis, characterization and performance evaluation of three phthalimide and three succinimide copolymers of vinyl acetate, styrene and methyl methacrylate as flow improvers for waxy crude oil. The prepared copolymers were named as; (VA)Ph; (St)Ph; (MMA)Ph; (VA)S; (St)S and (MMA)S. These copolymers were characterized by FTIR and ¹H NMR spectroscopy. The molecular weights and nitrogen content of these copolymers were determined by using the GPC technique and the Kjeldhal method, respectively. The rheological properties of crude oil (with and without additives) were studied. From the obtained results, it was remarked that the styrene phthalimide copolymer (St)Ph exhibited the maximum pour point depression (ΔPP_500 ppm = 30). The results of the rheological flow properties showed that the Bingham yield values (τ_β) for crude oil without additives at 15, 27 and 39 °C were 0.286, 0.131 and 0.075 Pa respectively, whereas the τ_β for the treated crude oil by the styrene phthalimide (St)Ph copolymer were 0.021, 0.0164 and 0.0081 Pa at 500 ppm at the same temperatures.     

Investigation of non-Newtonian flow characterization and rheology of heavy crude oil

The heavy crude oil exhibits a non-Newtonian shear thinning behavior over the examined shear rate. The viscosity of the heavy crude oil decreases about 15.6% when the temperature increased from 30 to 60°C. Heavy crude oil was blended with the aqueous solution of surfactant and saline water in different volumetric proportions of NaCl, and Na₂CO₃ solution mixtures. The addition of 50% of the mixture to the heavy crude oil causes a strong reduction in the viscosity, about 67.5% at 60°C. The heavy crude oil fits the Power law model since it has the lowest average absolute percent error of 0.0291. The flow behavior index of the heavy crude oil reaches a value of 0.9305 at a temperature of 30°C and it increases to 0.9373 when the temperature raises 60°C, while the consistence coefficient decreases from 2.8811 to 2.3558.     

大庆原油管输结蜡规律与清管周期的确定

在确定不同流态区管壁处剪切应力、蜡晶溶解度系数、径向温度梯度及管道沿线温降分布的基础上,回归建立了适用于描述大庆油田某两联合站间输油管道蜡沉积的结蜡模型。根据差压法原理,建立了研究原油管输结蜡过程室内模拟试验装置,并覆盖该输油管道的典型工况条件开展了管输原油结蜡模拟试验。相对偏差分析表明,结蜡模型预测结果与试验值的适配性良好。进而在预测运行时间对该输油管道结蜡影响的基础上,结合结蜡层厚度对管道轴向温降及压降的作用,确定了年季节最高与最低土壤温度期的清管作业周期分别为4个月和3个月。