Simulation of single phase non-Newtonian flow characteristics of heavy crude oil through horizontal pipelines

The effect of diameter, velocity, and temperature on flow properties of heavy crude oil in three horizontal pipelines using computational fluid dynamics (CFD) was studied. The flow characteristics were simulated by using CFD software, ANSYS Fluent 6.2. The mesh geometry of the pipelines having inner diameter of 1, 1.5, and 2 inch were created by using Gambit 2.4.6. From grid independent study, 221, 365 mesh sizes were selected for simulation. The CFD ANSYS Fluent 6.2 Solver predicted the flow phenomena, pressure, pressure drop, wall shear stress, shear strain rate, and friction factor. A good agreement between experimental and CFD simulated values was obtained.     

Emulsification of Indian heavy crude oil using a novel surfactant for pipeline transportation

The most economical way to overcome flow assurance problems associated with transportation of heavy crude oil through offshore pipelines is by emulsifying it with water in the presence of a suitable surfactant.In this research,a novel surfactant,tri-triethanolamine monosunflower ester,was synthesized in the laboratory by extracting fatty acids present in sunflower(Helianthus annuus)oil.Synthesized surfactant was used to prepare oil-in-water emulsions of a heavy crude oil from the western oil field of India.After emulsification,a dramatic decrease in pour point as well as viscosity was observed.All the prepared emulsions were found to be flowing even at 1°C.The emulsion developed with 60%oil content and 2wt%surfactant showed a decrease in viscosity of 96%.The stability of the emulsion was investigated at different temperatures,and it was found to be highly stable.The effectiveness of surfactant in emulsifying the heavy oil in water was investigated by measuring the equilibrium interfacial tension(IFT)between the crude oil(diluted)and the aqueous phase along with zeta potential of emulsions.2wt%surfactant decreased IFT by almost nine times that of no surfactant.These results suggested that the synthesized surfactant may be used to prepare a stable oil-in-water emulsion for its transportation through offshore pipelines efficiently.     

Emission characteristics of oxy-fuel combustion of crude oil in a fluidized bed combustor

One of the most important thermochemical methods for heat and electricity generation is combustion process; however, it has become a serious problem for researchers in the field of green chemistry due to high emissions and pollutants. In this paper, a modeling study of crude oil combustion was carried out based on the rate of reactions and combustor characteristics. To evaluate the potential of crude oil for heat and power generation, the influence of residence time of droplets and system pressure on greenhouse gas emissions was studied. Results obtained from model were validated against the experimental data of crude oil combustion and found to be in a good agreement.     

稠油溶解气驱泡沫油特征实验研究

压力衰竭速度是影响稠油溶解气驱泡沫油生产的一个关键因素。为定量描述压力衰竭速度对泡沫油现象的影响,实验选取了4组不同压力衰竭速度进行实验。研究不同压力衰竭速度下稠油衰竭开采中的采收率、产油量、生产气油比以及实验压力的变化。通过实验发现稠油溶解气驱过程中出现明显的泡沫油阶段,且压力衰竭速度越大,泡沫油拟泡点压力越小,泡沫油阶段越长。随着压力衰竭速度增加,采收率增加,生产气油比减小,油藏压力递减变慢。     

大杨树盆地原油显示及其地球化学特征

大杨树盆地位于内蒙古自治区东部的阿荣旗与鄂伦春自治旗境内，大地构造上属于内蒙一兴安岭褶皱系，兴安岭皱带的示部，为一北东东向长条状展布的中新生断陷盆地，面积为１５４６０km^2，沉积岩最大埋深为３２００m。     

原油沥青质在油藏岩石表面的吸附特性

选用两种原油沥青质样品，对沥青质在岩石孔隙表面的吸附及吸附所引起的润湿性变化进行了实验研究。对润湿性的测定结果表明，油藏岩石润湿性改变的程度主要取决于沥青质的来源和地层水的离子组成，同时也与离子浓度和岩样的束缚水饱和度有关。通过使用分光光度法测定沥青质在砂岩上的吸附量，初步建立了润湿指数（ＷＲ）与沥青质吸附量（ａ）之间的定量关系。对于某一给定的原油沥青质，ＷＲ值随ａ值增加而趋于降低。图４表３参１０（邓春萍摘     

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.     

In situ catalytic upgrading of heavy crude oil through low-temperature oxidation

The low-temperature catalytic oxidation of heavy crude oil (Xinjiang Oilfield, China) was studied using three types of catalysts including oil-soluble, watersoluble, and dispersed catalysts. According to primary screening, oil-soluble catalysts, copper naphthenate and manganese naphthenate, are more attractive, and were selected to further investigate their catalytic performance in in situ upgrading of heavy oil. The heavy oil compositions and molecular structures were characterized by column chromatography, elemental analysis, and Fourier transform infrared spectrometry before and after reaction. An Arrhenius kinetics model was introduced to calculate the rheological activation energy of heavy oil from the viscosity– temperature characteristics. Results show that the two oil-soluble catalysts can crack part of heavy components into light components, decrease the heteroatom content, and achieve the transition of reaction mode from oxygen addition to bond scission. The calculated rheological activation energy of heavy oil from the fitted Arrhenius model is consistent with physical properties of heavy oil (oil viscosity and contents of heavy fractions). It is found that the temperature, oil composition, and internal molecular structures are the main factors affecting its flow ability. Oil-soluble catalyst-assisted air injection or air huff-n-puff injection is a promising in situ catalytic upgrading method for improving heavy oil recovery.     

Rheological and physicochemical characterization of UAE crude oil

This study focuses on the rheological and physiochemical characterization of three samples of light crude oil and fuel oil from the United Arab Emirates. The dependence of density on temperature ranging from 20 to 200°C was determined. Also, the impact of temperature was investigated on viscosity, shear stress τ, shear rate, yield stress, and thixotropic behavior, and characterized by the Haake RheoStress. The exponential decrease of viscosity over temperature range was modeled using Arrhenius equation. The shear stress–viscosity data revealed that crude oil A solely exhibited Newtonian behavior while crude oils B and C and fuel oil followed the Herschel-Bulkley model.     

Upgrading of crude oil via distillation processes

Distillation is a unit operation of separating the components from a liquid mixture by selective evaporation and condensation. To obtain a pure liquid by distillation of a mixture must be applied in this process, numerous consecutive. Multistage distillation usually preferred instead of a single stage distillation. Fractional distillation is an example of a multistage distillation. Industrial-scale productions in all multistage or multitray distillation are applied. The composition of crude varies with its origin or geographical location. The contents of crude oil can be separated into different fractions with a series of fractional distillation processes.     

劣质原油加工方案的优化与探索

长岭分公司根据原油性质数据,预测了不同混合原油的加工方案及产品性质,通过生产实践,摸索出一套适宜的生产方案和加工流程,成功加工了高硫劣质的纳波等原油,确保了产品质量和安全平稳生产,为含硫燃料型炼油厂加工高硫重质原油提供了参考经验。     

油井生产中原油脱气对结蜡的影响分析

对于饱和压力较高的油井，脱气导致的结蜡问题已引起人们的关注，但目前大多还只是停留在感性认识的阶段。该文通过大量的实验数据的统计与对比研究，定量地分析了脱气对原油粘度、密度、原油析蜡点的影响．提出原油中含气比较高的区块，其油井生产中要尽可能地使原油少脱气，以减少蜡的析出的结论。同时提出类似于华152井区的含气原油体系当压力低于3MPa（气油比低于30m^3／t）时，原油粘度会迅速增加，C1-C7低分子量的饱和烃含量会迅速减少，原油结蜡程度会大幅度增加。     

Determination of wax content in crude oil

Wax deposition is one of the chronic problems in the petroleum industry. The various crude oils present in the world contain wax contents of up to 32.5%. Paraffin waxes consist of straight chain saturated hydrocarbons with carbons atoms ranging from C18 to C36. Paraffin wax consists mostly with normal paraffin content (80–90%), while, the rest consists of branched paraffins (iso-paraffins) and cycloparaffins. The sources of higher molecular weight waxes in oils have not yet been proven and are under exploration. Waxes may precipitate as the temperature decreases and a solid phase may arise due to their low solubility. For instance, paraffinic waxes can precipitate out when temperature decreases during oil production, transportation through pipelines, and oil storage. The process of solvent dewaxing is used to remove wax from either distillate or residual feedstocks at any stage in the refining process. The solvents used, methyl-ethyl ketone and toluene, can then be separated from dewaxed oil filtrate stream by membrane process and recycled back to be used again in solvent dewaxing process.     

稠油油藏水平井双管吞吐技术

针对稠油油藏水平井热采开发过程中水平段蒸汽沿程的吸汽量不同导致油层动用程度不均问题,进行了水平井双管吞吐技术研究.该技术从水平段跟端和指端同时注汽,并根据吸汽情况在井口对跟端和指端注汽量进行适时调整,解决了水平段吸汽不均问题.通过吸汽剖面和井底压力场的分布对比了水平井常规吞吐与水平井双管吞吐的区别,提出了水平井双管吞吐"卧8"字的势场分布模式.结合现场实例证明了水平井双管吞吐工艺的优势和可行性.     

Interfacial activity of alkyl hydroxyl sulfobetaine against crude oil

To study the interfacial activities of zwitterionic surfactant against crude oil, four alkyl hydroxyl sulfobetaines were synthesized. The effects of surfactant structure, concentration, salinity of formation water, and crude oil composition on interfacial activities were discussed. It shows that the octadecyl hydroxyl sulfobetaine can achieve ultralow interfacial tension at the concentrations no less than 0.001%, exhibiting a good interfacial activity and a very strong antidilution ability. The salinity of formation water has no obvious effect on lowering the interfacial tension and the polar component in crude oil is very crucial for the production of ultralow interfacial tension. This work is important for enhanced oil recovery.     

Wettability and morphology of mica surfaces after exposure to crude oil

Reservoir wettability is determined by interactions between crude oil and mineral surfaces, mediated by an aqueous phase. Contact angles between immiscible fluids have long been used as probes to assess the effective wetting condition of surfaces after exposure to brine and oil, but there is a limit to the amount of information that can be deduced from contact angles in such nonideal conditions.In this study, atomic force microscopy (AFM) has been used to observe mica surfaces treated with a series of crude oils that produce a wide range of wetting conditions—water-advancing contact angles on these surfaces vary from water-wet to oil-wet. In the most water-wet case, the only adsorbed features appear to be small, water-wet particles that are probably inorganic. All of the other oils deposited organic coatings, with varying thickness, morphology, and durability. Weakly water-wet systems exhibited many surface features, but the waitings tended to be unstable and to detach from the surface, especially during AFM scanning in water. The most oil-wet systems exhibited thick, stable organic coatings that were not disturbed by AFM scanning.     

稠油油藏水平井生产特点及效果影响因素分析

针对辽河油田稠油油藏水平井的应用状况,为进一步改善水平井开发效果,在对普通稠油、特稠油、超稠油3种油品稠油油藏水平井生产数据进行统计的基础上,对其开采特点及原因进行分析得出,其开采特点既有与直井相似之处,又有自身的生产特点;投产条件及吞吐周期内加热长度和加热半径的不同是造成水平井自身开采特点的主要原因。通过对具有不同水平段长度和目的层厚度水平井的开发数据进行统计分析得出,在目前的注汽和工艺技术条件下,目的层厚度对生产效果的影响程度较水平段长度明显一些,提高水平段的动用程度将是改善现有水平井开发效果的主要方向之一。     

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.     

辽河油区原油密度与温度关系的统计方程

根据辽河油气区１８ 个油田近２０００ 个原油样品分析统计,原油密度是温度的幂函数。由此建立两个原油密度与温度关系的通用方程, 可计算各种油品（ 稀油、稠油、凝析油和高凝油） 在任一温度下的脱气原油密度,计算值的最大相对误差为２ ．８８‰,平均为０ ．３７‰～０ ．７５ ‰。应用这两个方程可降低６０ ％ 的原油分析成本,还为原油分类提供了准确可靠的密度数据。     

Optimization of petroleum crude oil treatment using hydrogen sulfide scavenger

Hydrogen sulfide scavenging is one of the preferred methods for minimizing the operational risks and corrosion in crude oil production facilities. This paper deals with the determination of the optimum values of retention times of scavenging hydrogen sulfide from the crude oil produced at different conditions in one of the Egyptian petroleum companies using EPRI H₂S scavenger solution (one of the chemical products of Egyptian Petroleum Research Institute). The retention time depends on several operating condition variables such as injection dose rate, pipe length, pipe diameter, crude oil velocity, pressure and inlet H₂S concentration. The hydrogen sulfide scavenger injected into the crude oil pipeline must be contacted with the crude oil for a suitable a specified time (retention time) to reduce the concentration of H₂S to the desired value which is usually less than 10 ppmv. The optimization results were obtained using the software program LINGO. It was found that the optimum values of H₂S scavenger retention time of the scavenging of hydrogen sulfide are increased by increasing the pipe diameter and the inlet H₂S concentration, while decreased by increasing the pipe length, gas molar mass velocity, injection dose rate, crude oil velocity and pressure.