TLC-FID Calibration and Accurate Weight Determination of SARA Fractions in Heavy Crude Oil

Abstract

The authors specifically aimed to separate and characterize clean saturates, aromatics, resins, and asphaltenes (SARA) fractions and develop standards for accurate quantification purposes. A standard method ASTM D4124-86 was employed for the SARA separation of an Athabasca crude oil. These four recovered fractions were analyzed by using an Iatroscan thin-layer chromatograph with flame ionization detection (TLC-FID). The Iatroscan response to the complete burnoff of known sample weights of each fraction deposited on chromarods via known volumes of standard solutions was determined and area count versus sample weight calibration graphs subsequently obtained. From the established weight versus peak area calibration curves for each pure separated SARA fraction their accurate quantitative percentage in an Athabasca heavy crude oil was determined.     

Hydrotreating of Furrial Crude Oil Using NiMoS Supported on Alumina: Study of the Asphaltene and Their Fractions in Cyclohexane

Abstract

The Furrial crude oil originated in northern Monagas State. This shows problems such as the colloidal instability of the asphaltenes fraction present in them, causing its precipitation. This work is oriented to achieve an interpretation of the colloidal behavior of the asphaltenes through the study of the effect of the hydrotreating reactions (HDT) on the asphaltenes of the Furrial crude oil, using NiMoS/γ-Al₂O₃ as a catalyst. The results obtained after HDT reactions were analyzed to know the percentage of asphaltene and their fractions in cyclohexane, the measurement of flocculation thresholds and molecular weights by the VPO technique, and ¹³C NMR as well as the determination of the total sulfur content. Appreciable changes on the asphaltene of the Furrial crude oil and its fractions in cyclohexane after HDT, under conditions used, were observed. In general terms, the amount of asphaltene diminished and the percentage of distribution for insoluble fraction in cyclohexane (IFC) and for soluble fraction in cyclohexane (SFC) was affected causing an increase in the stability of the asphaltene. The asphaltene and IFC were observed to be a pronounced variation of the molecular weight average in number, in comparison with SFC. ¹³C NMR spectra indicate that the hydrotreated asphaltene shows structural change, and IFC presents a variation of the percentage of sulfur minor in comparison to SFC.     

Prediction of Asphaltene Precipitation in Live and Tank Crude Oil Using Gaussian Process Regression

The study of asphaltene precipitation properties has been motivated by their propensity to aggregate, flocculate, precipitate, and adsorb onto interfaces. The tendency of asphaltenes to precipitation has posed great challenges for the petroleum industry. Since the nature of asphaltene solubility is yet unknown and several unmodeled dynamics are hidden in the original systems, the existing models may fail in prediction the asphaltene precipitation in crude oil systems. The authors developed some Gaussian process regression models to predict asphaltene precipitation in crude oil systems based on different subsets of properties and components of crude oil. Using feature selection techniques they found some subsets of properties of crude oil that are more predictive of asphaltene precipitation. Then they developed prediction models based on selected feature sets. Results of this research indicate that the proposed predictive models can successfully predict and model asphaltene precipitation in tank and live crude oils with good accuracy.     

Prediction of the Kinematic Viscosity of Crude Oil Fractions

Abstract

A generalized equation based on modified Eyring's theory for predicting kinematic viscosity of petroleum fractions is proposed in this work. The equation uses two reference fluids including a pair of (C6 and C10), (C10 and C14), or (C14 and C20) for petroleum fractions of molecular weight higher than 70 and lower than 300.

Validity and accuracy of this equation have been confirmed by comparing the obtained results of this equation with experimental data. In contrast to other correlations that require so many specific parameters for oil viscosity prediction, this type of equation requires only molecular weight and true boiling point. The results obtained in this work are in agreement with experimental data with an average absolute deviation (AAD) of less than 5%.     

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。     

The Effect of Solvent Nature and Dispersant Performance on Asphaltene Precipitation from Diluted Solutions of Instable Crude Oil

Abstract

The asphaltene precipitation experiments were studied on El Furrial crude oil from western Venezuela, which is known to exhibit serious instability problems. A Turbiscan backscattering apparatus was used to evaluate the precipitation of asphaltenes with different solvents. The transmittance variation with time was studied as the crude was diluted with heptane, pentane, and cyclohexane. Linear alkanes-containing systems exhibit a two-stage behavior, whereas only one is found when diluting with cyclohexane. Dispersing agents were tested by using the precipitate height as a criterion of effectiveness. Results are reported for ethoxylated nonylphenols and a commercial dispersant.     

Dispersion Properties of NMR Relaxation for Crude Oil

Special requirements for design of tools used for wireline NMR logging and NMR logging while drilling and for interpretation model are demanded due to the dispersion properties of NMR relaxation for crude oil. NMR longitudinal relaxation time (T_1) and transverse relaxation time (T_2) of the dead oil samples with different viscosities were measured by NMR spectrometers with a Larmor frequency of 2 MHz and 23 MHz at five different temperatures respectively. The results showed that T_1 was obviously dependent on the Larmor frequency of NMR spectrometer. The degree of T_1 dispersion became stronger with the increasing crude oil viscosity, Larmor frequency and the viscosity/temperature ratio. T_2 was independent of NMR spectrometer measuring frequency. It is suggested that the resonance frequency should be selected lower than 2 MHz when measuring T_1 in logging while-drilling and that T_1 dispersion should be corrected when Larmor frequency is higher than 2 MHz.     

Separation and Characterization of Naphthenic Acids Contained in Penglai Crude Oil

Abstract

Naphthenic acids were separated from highly acidic Penglai crude oil by aqueous alkaline solution and analyzed by infrared spectrum (IR) and mass spectrum (MS). According to our results, the solution was composed of ethanolamine, alcohol, and water, the ratio being 0.1:7.9:10. When the solution and crude oil (ratio 0.4:1) were stirred at the speed of 300–400 r/min at 50°C for at least 10 min, more than 70% of the naphthenic acids in the crude oil could be removed. IR and MS results confirmed the presence of diversified naphthenic acids in Penglai crude oil and provided relative content information.     

南堡凹陷原油芳烃地球化学特征

通过对南堡凹陷原油GC-MS分析,研究了原油芳烃组成特征,探讨了原油成因。结果表明,南堡凹陷原油主要形成于弱氧化的淡水湖相沉积,为成熟原油。通过芳烃化合物组成及萘系列、联苯系列化合物内部相对丰度关系表明．沙河街组原油与东营组、馆陶组原油在源岩有机质输入方面有一定的差异,其中东营组和馆陶组原油有机质输入中高等植物有较大贡献,可能来源于南堡凹陷东三段或沙一段烃源岩,而沙河街组原油来源于沙三段烃源岩。     

Prediction of wax content in crude oil and petroleum fraction by proton NMR

In this study, we develop a simple method for estimation of wax content in crude oil and their fractions. The traditional way of wax estimation follows low-temperature chemical extraction based gravimetric methods; those are tedious, time-consuming, need a lot of chemicals and solvents and may produce an erroneous result if not done properly. This study proposes an alternative method i.e. ¹H NMR based correlation study to Englar Holde’s wax determination method. In this study, the NMR derived structural parameters of petroleum fractions are used to estimate the wax content of petroleum fractions. A Model equation is developed based on Fourier equation and validated with different Indian origin samples with a proper fitting and high predictability.     

原油乳状液稳定性研究 Ⅱ.原油成分对原油乳状液稳定性的影响

原血成分的表面活性物质及其细微固体颗粒,在油水界面上相互作用是原油乳状液其有稳定性的主要原因。本文采用简单的方法将原油中众多的物质分成两大类,并根椐它们单独时或混合后对癸烷/水乳状液稳定性作用的特征,将其分别称为原油乳化剂和原油破乳剂。试验表明,原油乳状液稳定性的高低主要取决于所含的这两大类物质的多少和相对比例,其相对重要性可由界面张力定性地反映出来;并且由原油/水界面张力的大小可以定性地评估原油乳状液的稳定性。     

Structural Characterization of Asphaltenes and Ethyl Acetate Insoluble Fractions of Petroleum Vacuum Residues

Asphaltenes and insoluble fractions of vacuum residues (VRs) of two Indian crude oils (viz. Heera and Jodhpur) of different specific gravity were obtained by precipitation of VRs in n-hexane, n-heptane, and ethyl acetate, and also by subsequent reprecipitation of n-heptane and ethyl acetate soluble fractions by n-pentane. The effect of various solvents on average molecular structure of asphaltenes and insolubles was studied using nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR), and size exclusion chromatography (SEC). The asphaltenes and insolubles of Jodhpur VR have higher amounts of high molecular weight species with a high concentration of condensed and substituted aromatic rings, branched and/or short alkyl side chains, oxygen and nitrogen functionalities, compared to that of Heera VR. Ethyl acetate insolubles comprise a higher number of substituted aromatic structures, branched aliphatic structures, complex average unit structures, nitrogen and oxygen functionalities, and high molecular weight (MW) species as compared to hexane and heptane asphaltenes. Heptane insolubles consist of more naphthenic rings condensed with aromatic rings than C6A and EAI.     

混炼原油的评定与研究

将大庆原油与俄罗斯原油按不同比例混合，并分析实沸点切割的宽馏分性质，结果表明：随着进口油比例的增加，混炼原油的粘度和凝点都随之降低，有利生产低凝的煤油，柴油。混合比为50：50时轻质油收率最大，60：40时总拔出率最高。     

Interfacial and Structural Properties of Different Natural Surfactants Extracted From Venezuelan Junin Extra Heavy Crude Oil

Abstract

In this work, acids, asphaltenes, maltenes, and acid-free asphaltenes were isolated from Venezuelan Junin extra heavy crude oil, and their interfacial properties studied using the pendant drop method. This study led to the conclusion that the acids present in the crude, which have molecular weights of about 400 Da and are present in higher concentrations in asphaltenes, account for the decrease in the interfacial tension. In other words, asphaltenes act as molecular traps for acids. Furthermore, it was possible to confirm with simpler methods that substances adsorbed at the water–crude oil interface have low molecular weights.     

一种高效原油破乳剂的组成结构剖析

报道了用仪器分析法剖析美国冠军公司所产高效原油破乳剂DM476的组成、结构的结果。该剂强亲油弱亲水，用亚甲基蓝法检测含有阴离子表面活性剂。将脱除溶剂和低分子杂质的该剂溶于氯仿，在色谱柱上用极性递增的有机溶剂淋洗，分离为占比例较大、极性较大的主组分和占比例较小、极性较小的次组分。对主组分进行了红外光谱、核磁共振氢谱、碳谱分析，对次组分进行了红外光谱、核磁共振氢谱及质谱分析，判定主组分为叔丁基酚醛聚氧乙烯聚氧丙烯嵌段聚醚的磺酸酯，含有很少量聚环氧乙烷，次组分为烷基（叔丁基）酚聚氧乙烯醚，分子量小。图6参7。     

塔里木盆地原油裂解成气动力学实验

基于高压(50 MPa)下黄金管生气动力学实验,对塔里木盆地不同原油样品裂解成气组分产率特征与动力学参数进行了研究,并探讨了地下原油的热稳定性.结果表明,牙哈5井原油、哈得4-87井原油样品裂解具有很高的总气态烃产率(分别高达738.87和598.98 mL/g)和大量的C2-5烃产率(分别为256.85和188.63 mL/g);原油样品裂解生成甲烷的活化能分别为276.3～347.5 kJ/mol、263.8～351.7 kJ/mol;频率因子分别为2.07×1016s-1、1.42×1016s-1.地质条件下,牙哈5井原油、哈得4-87井原油的消失温度分别为197～220.8℃和186.5～212℃.     

莺歌海盆地原油中微量元素分布特征及其地质意义

采用同步辐射X射线荧光分析技术 ,测定了莺歌海盆地海相原油和北部湾盆地陆相原油中的微量元素含量 ,结果是海相原油富集Cr、Mn、Fe元素 ,陆相原油Cr、Mn、Fe元素含量甚微 ,但却富集Cu元素。如此特征为判识原油的成因类型和源岩追踪提供了有意义的信息     

原油脱盐脱水技术研究进展

介绍了各种原油脱盐脱水技术,主要包括超声波法、电化学法、微波辐射法等,简述了各种技术的脱盐脱水原理及发展现状。     

润滑油基础油与原油的价格联动性研究

文章以2008年1月8日至2013年4月26日间的基础油价格和国际原油价格数据为样本,实证分析了二者之间的价格联动关系。得出结论为:基础油价格与国际原油价格之间存在长期均衡关系,Granger因果检验表明国际原油价格与基础油价格之间存在因果关系,脉冲响应函数和方差分解表明国际原油价格对基础油价格产生的影响较显著。最后,针对基础油价格的制定提出了相关建议。     

YL-2025破乳剂用于管输原油破乳脱水研究

通过评价十多种油溶性破乳剂单剂对管输原油乳液的脱水效果,筛选出2种脱水性能较好的破乳荆,按一定比例复配出一种复合性油溶性破乳剂YL-2025。试验证明该破乳剂对管输原油具有良好的脱盐脱水效果。在中国石油化工股份有限公司武汉分公司联合装置上进行了工业应用,应用2个月后的检测结果表明,脱盐脱水合格率迭90％以上。