含蜡原油胶凝过程特性研究

利用RS75流变仪在小振幅振荡剪切的模式下分别研究了3种不同历史条件下含蜡原油的胶凝过程, 同时通过偏光显微镜观察了不同降温速率条件下原油中的蜡晶形貌. 结果表明, 在静态降温条件下, 降温速率越大, 原油胶凝的温度越低, 原油形成的胶凝结构越弱; 并且降温速率越大, 原油在恒温静止过程中, 结构随时间恢复的速率越大, 恢复至平衡所需时间越长, 但最终的平衡结构却越弱; 在同样的降温速率下, 原油低温胶凝结构随着降温过程中剪切作用的增强而减弱, 但当历史剪切速率超过一定数值时, 原油的胶凝结构将基本不再继续变化; 在同样的历史剪切速率下, 降温速率越大, 原油在低温(31 ℃)静止初始的储能模量越小, 但最终的平衡结构却越强.     

综合模拟风化条件下渤海原油中生物标志物及多环芳烃风化规律研究

该文以渤海原油SZ36-1为研究对象进行综合模拟风化实验,探讨了原油中生物标志物及5类多环芳烃(PAHs)组分的分布情况及风化规律。结果表明:经过30 d风化,渤海原油SZ36-1中大部分生物标志物表现出强的稳定性,部分PAHs的分布发生较大改变,其中萘系列化合物损失最严重,相对浓度的损失达80.34%;菲、二苯并噻吩、、芴系列则相对稳定;经t检验分析风化样品测试数据,生物标志物诊断比值表现出良好的稳定性,所选取多环芳烃新诊断比值中,菲和系列、烷基取代二苯并噻吩类、烷基取代芴类的抗风化能力较强,可用于油源鉴别。     

基于费谢尔判别法的原油、燃料油鉴别技术研究

对原油、燃料油的鉴别方法进行了研究.以来自不同国家和地区的30个原油样品以及不同产地、不同种类的24个燃料油样品中的正构烷烃(n-C7～30)、植烷(Ph)、姥鲛烷(Pr)的含量构成训练集.借助SPSS 16.0进行费谢尔(Fisher)判别分析,建立Fisher判别函数.将判别变量值代入后,得到样本的空间位置,再计算样本至各组重心的距离,据此判断分类情况.结果表明,Fisher判别法可以很好地用于原油和燃料油的鉴别,具有快速、准确等特点.     

费谢尔判别法鉴别原油/燃料油

以多环芳烃作为变量,建立了原油、燃料油属性鉴别的费谢尔判别法。分别测定了来自不同国家和地区的26个原油样品和25个燃料油样品中8种多环芳烃的含量,并将它们作为判别变量。借助SPSS 16.0进行费谢尔判别分析,建立费谢尔判别函数。将未知样品的判别变量值代入后,可以快速地得知样品的类别。结果表明,以多环芳烃作为判别变量进行原油、燃料油费谢尔判别快速而准确。     

降凝剂与原油组分相互作用的影响因素及降凝剂发展

概述了含蜡原油中的蜡、胶质、沥青质、轻烃等有关组分与降凝剂的相互作用特点，及其对原油改性效果的影响。并结合降凝剂的改性原理，对降凝剂的发展进行了介绍。     

塔里木塔河原油中钒卟啉的分离和鉴定

石油卟啉的存在是石油有机成因说的重要证据之一，并且根据石油卟啉的类型和分布可以推测石油的沉积环境及成熟程度。另一方面，石油中的卟啉主要是镍卟啉和钒卟啉，镍和钒是石油加工过程中裂化催化剂失活的主要原因，对石油卟啉的认识将有助于脱金属工艺的开发，从而降低镍和钒对加工过程的不利影响。     

Evaluation of Measurement Methods of Waxy Crude Oil Thixotropy

The thixotropy of three waxy crude oils was measured to evaluate different measurement methods using RheolabQC. The results showed that the average relative deviation using the hysteresis loop method was 24.4%, the lowest among the methods evaluated. The method of stepwise-increase in shear rate was able to obtain several rheological characteristics from a single experiment, and such a thixotropic experiment can be performed with any rheometer. This makes the stepwise-increase in shear rate the method of choice when considering convenience. However, the method of hysteresis loop is preferable when it comes to the reliability of measuring thixotropic parameters.     

Separation and Chemical Characterization of Wetting Crude Oil Compounds

To improve the understanding of wettability, especially the influence of colloidal stability and composition of crude oil, wetting experiments on quartz sand were performed with an asphaltene-rich oil, a resin-rich oil, and with model oils containing different colloid compositions. A two-step procedure was developed to investigate the wetting behavior. In the first step those crude oil components were extracted, which preferentially wet solid surfaces. The extracted crude oil components were characterized in the second step. The amount of adsorbed oil components correlates with the stability of the crude oil colloids: low colloidal stability of crude oil leads to larger amounts of adsorbed components than does high colloidal stability. The addition of resins and/or low molecular weight asphaltenes to the crude oil stabilizes the crude oil colloids; i.e., a lower amount of wetting components are isolated by extraction in such systems. To find out, which fraction of the adsorbed oil components determines the wetting behavior of a crude oil, the wetting properties of the toluene solutions of these fractions were compared to those of the toluene solutions of the precipitated crude oil colloids. The fractions extracted with the solvent systems chloroform and methanol/chloroform showed nearly the same wetting behavior as the crude oil colloids. These fractions are characterized by the highest molecular weights, higher sulfur compositions, and the lowest H/C ratios. On the other hand, the nitrogen compounds predominate in the acetone fraction.     

大庆原油中石油羧酸组成的GC-MS分析

用碱抽提法从大庆原油中分离石油羧酸，通过硅胶柱层析法将石油酸分为5个不同的馏分，分别对3个极性馏分的甲酯化产物进行GC－MS结构鉴定，大庆原油含有C9－C24全部系列正构饱和脂肪酸、多种异构饱和脂肪酸及不饱和脂肪酸，乙酸乙酯馏分在整个洗脱分离物中的量占最大比例，而且几乎集中了所有的异构脂肪酸。     

Effect of Wax Composition and Shear Force on Wax Aggregation Behavior in Crude Oil: A Molecular Dynamics Simulation Study

To explore the influence of different wax components and the shear effect exerted by the pump and pipe wall in the process of crude oil pipeline transportation on the microbehavior of wax aggregation in crude oil at low temperatures, molecular dynamics models of binary and multivariate systems of crude oil with different wax components are established in this paper. The simulation results are compared with the existing experimental results and the NIST database to verify the rationality and accuracy of the models. By using the established binary model to simulate four crude oil systems containing different wax components, it can be found that the longer the wax molecular chain, the more easily the wax molecules aggregate. The influence of temperature on the aggregation process of wax molecules with different chain lengths is also studied. The lower the temperature, the greater the difference in wax molecular aggregation degree caused by the difference in molecular chain length. Nonequilibrium molecular dynamics is used to simulate the shear process of a multivariate system of crude oil, and the micromechanisms of the shear effect on the aggregation process of wax molecules are studied. Shearing can destroy the stable structure of crude oil, resulting in the orientation and conformational transformation of wax molecules, and obtaining the region of wax molecules sensitive to temperature and shear effects, the temperatures of which are below the wax precipitation point and the shear rate of which is lower than the maximum shear rate to prevent the molecular structure from being destroyed. At the same time, the sensitivity of wax components with different chain lengths to the shear effect is studied. The research results provide theoretical guidance for ensuring the safe and economic operation of waxy crude oil production.     

Feasibility Study of Crude Oil Fields by Thermal Analysis Techniques

This paper investigates the minimum oil content necessary for self-sustained combustion, which is introduced as a criterion for the selection of suitable reservoirs for in-situ combustion processes. Differential scanning calorimetry was used to determine the heat values of oil-limestone mixtures. The minimum temperature required for the total consumption of the fuel was obtained by thermogravimetry (TG/DTG). The minimum amount of oil necessary to sustain combustion was calculated from these two parameters and compared with the oil content of the reservoir. Reservoirs with an oil content greater than or equal to this minimum value were considered feasible. It was seen that the fields examined are generally not suitable for in-situ combustion processes. This revised version was published online in August 2006 with corrections to the Cover Date.     

马瑞原油在空气和氮气中的热解-氧化性能

低温氧化是注空气采油及原位燃烧采油技术中的重要化学反应,为深入认识原油在有氧环境下复杂热反应过程中的低温氧化特性,我们采用热重/差热分析法(TG/DTA)研究了线性升温和等温条件下马瑞(Merey)原油的热反应行为。 结果表明,Merey原油在空气及线性升温条件下的受热过程分4个阶段:气化段、低温氧化段、热解段和高温氧化段;相邻阶段的物理、化学主导过程的重叠增加了分析原油热反应特征的难度。 升温速率提高,气化段和低温氧化段的终止温度不变;热解段和高温氧化段的终止温度以及热解段的峰温随升温速率的增加而升高。 N₂气与空气下Merey原油的热重/微分热重(TG/DTG)数据对比表明,升温速率越高,空气下的高温氧化段与热解段重叠程度越大,这有利于燃烧但会降低原油采收率。 空气下等温时的TG/DTA结果表明随升温速率增加,升温至300 ℃时的失重率降低,不利于原油轻组分的气化。 反应温度越高,气化过程时间越长,失重分数越大。 Merey原油在低于300℃时低温氧化反应不是主导反应。     

原油中芳香硫化合物形态分布的研究

建立了原油中多环芳香硫化合物形态分布的研究方法。采用氯化钯/硅胶配位交换色谱分离原油中的芳香硫化合物,并用气相色谱/质谱分析、气相色谱-硫化学发光检测法结合色谱保留指数,鉴定出原油中的100多个多环芳香硫化物,包括含烷基取代基的苯并噻吩和二苯并噻吩类硫化物。定量分析表明,二苯并噻吩类化合物的含量占芳香硫化合物总量的91%左右。该方法可用于不同来源的原油中芳香硫化合物的形态分布研究。     

原油及重油的快速分析技术进展

近年来,随着我国原油加工量的不断增加,加工难度的不断增大,原油快速评价问题日益受到重视.原油评价是指在全面分析原油的物理及化学性质的基础上,对原油的可加工性能及加工过程中可能出现的问题进行综合分析的过程.目前飞速发展的计算机技术及仪器分析技术,为原油快评技术奠定了良好的基础.该文以不同分析方法进行分类,介绍了近红外光谱(NIR)、中红外光谱(IR)、核磁共振波谱(NMR)及其他分析方法在原油和重油快速分析领域的技术进展.     

Quantitative and Qualitative Analysis of Three Classes of Sulfur Compounds in Crude Oil

Owing to the environmental hazards arising from sulfur‐containing combustion products, strong legal regulations exist to reduce the sulfur content of transportation fuels down to a few ppm. With the ongoing depletion of low‐sulfur crude oil reservoirs, increased technological efforts are needed for crude oil refining to meet these requirements. The desulfurization step is a critical part of the refining process but partly suffers from the recalcitrance of certain species to sulfur removal and the inability to quantitatively understand the behavior of individual compound classes during the process. We herein present a new and simple approach for the parallel quantification of three different classes of sulfur species present in crude oils by LC separation and on‐line detection and quantification by ICP‐MS/MS. This approach will help to estimate the amount of recalcitrant species and thus facilitate the optimization of desulfurization conditions during fuel production.     

低温氧化对原油组成的影响

通过空气与原油在油藏温度和一定压力下低温氧化过程的模拟实验,对反应前后气体与原油的组成进行分析.结果表明,实验条件下低温氧化反应后原油芳烃含量减少,胶质含量增加,饱和烃含量和沥青含量基本不变,正构烷烃轻重组分比增加;原油黏度有所增加.     

压力对塔里木原油四组分热解性能的影响

压力对深层油藏原油热化学过程的影响尚存在较大争议,为研究其在油藏原油热解成气过程中的作用机理,我们在450℃、5~40 MPa压力下对塔里木原油四组分(饱和分、芳香分、胶质和沥青质)进行了封闭体系的热解实验,通过气相色谱(GC)和气相色谱/质谱(GC/MS)分别对原油四组分热解反应的气体产物及饱和分热解过程的液态产物进行了分析。结果表明,在450℃、24 h及不同压力下,沥青质热解产气率高于胶质、芳香分和饱和分;四组分的气相热解产物中,C1的产率明显高于C2~C5组分。增大压力抑制沥青质、胶质及芳香分的热解产气过程而促进饱和分的热解产气过程。随压力的增大,饱和分热解的液态产物的主峰组分碳数先减小,再增大。压力低于20 MPa时,饱和分热解过程中以裂解反应为主;高于30 MPa时,增大压力有利于缩合反应。研究结果可为认识深层油藏原油的稳定程度及天然气的成因提供一定的理论参考。     

辽河超稠原油的流变性质及其乳化降粘

研究了辽河超稠原油在不同温度下的流变性质，进行了辽河超稠原油的乳化降粘试验，研制出比较适宜的乳化降粘剂BHJ，制备出稳定性好、粘度适中的水包油型超稠原油乳状液。在乳化剂加量为6‰－1％的情况下，最大降粘率达到90％以上。并对超稠原油乳状液的流变性质、微观结构及燃烧特性进行了初步探讨。     

Strain-Dependent Rheological Model and Pressure Wave Prediction for Shut in and Restart of Waxy Oil Pipelines

Waxy oil gelation and rheology is investigated and modeled using strain-dependent viscosity correlations. Rotational rheometry shows a sharp viscosity increase upon gel formation. High creeping flow viscosities are observed at small deformation conditions prior to yielding. A new strain-dependent rheological model, following analogous formulation to the Carreau–Yasuda shear rate-dependent model, captures viscosity reduction associated with yielding. In addition, shear viscosity and extensional viscosity are investigated using a capillary rheometry method. Distinct shear-thinning behavior is observed in the shear mode of deformation, while distinct tension-thinning behavior is observed in the extensional mode of deformation for the model fluid systems. High Trouton ratios are obtained for the gelled model fluid systems, confirming strongly non-Newtonian fluid rheology. Finally, axial pressure wave profiles are computed at real pipeline dimensions for idealized moderate yield stress fluids using a computationally efficient 1D pipeline simulator. The Rønningsen time-dependent gel degradation model is used to emulate the fluid rheology in the simulator. Axial stress localization phenomena are shown to depend on the overall magnitude of gel degradation as established by the reduction in yield value. A high degree of gel degradation serves to afford flow commencement in a timely manner.