Flow Characteristics of Crude Oil with High Water Fraction during Non-heating Gathering and Transportation

In order to ensure the safety of the non-heating gathering and transportation processes for high water fraction crude oil,the effect of temperature,water fraction,and flow rate on the flow characteristics of crude oil with high water fraction was studied in a flow experimental system of the X Oilfield.Four distinct flow patterns were identified by the photographic and local sampling techniques.Especially,three new flow patterns were found to occur below the pour point of crude oil,including EW/O&W stratified flow with gel deposition,EW/O&W intermittent flow with gel deposition,and water single-phase flow with gel deposition.Moreover,two characteristic temperatures,at which the change rate of pressure drop had changed obviously,were found during the change of pressure drop.The characteristic temperature of the first congestion of gel deposition in the pipeline was determined to be the safe temperature for the non-heating gathering and transportation of high water cut crude oil,while the pressure drop reached the peak at this temperature.An empirical formula for the safe temperature was established for oil-water flow with high water fraction/low fluid production rate.The results can serve as a guide for the safe operation of the non-heating gathering and transportation of crude oil in high water fraction oilfields.

Reservoir geochemistry of the Tazhong Oilfield in the Tarim Basin, China, Part II. Migration, accumulation and mixing of crude oils

Measurements of the absolute and relative concentrations of nitrogen-containing compounds in crude oils from different reservoir strata (Ordovician, Silurian and Carboniferous) in the Tazhong region of the Tarim Basin, Xinjiang, China, showed that even though there are quite a number of factors affecting the distributional and compositional characteristics of neutral nitrogen-containing compounds in crude oils, the distributional and compositional characteristics of crude oils whose source conditions are approximate to one another are influenced mainly by the migration and fractionation effects in the process of formation of oil reservoirs. In addition, crude oils in the Tazhong region show obvious migration-fractionation effects in the vertical direction. Carboniferous crude oils are characterized by high migration parameters and low compound concentrations, just in contrast to Ordovician crude oils. This indicates that crude oils from shallow-level oil reservoirs were derived from those of deep-level oil reservoirs via faults, unconformable contact or carrier beds. Crude oils from the Tazhong region show some migration-fractionation effects in the lateral direction, but mixing of crude oils derived from different hydrocarbon source rocks in the process of formation of oil reservoirs made it more complicated the migration and accumulation of crude oils, as well as the formation of oil reservoirs.

First Evidence of Fungal Strains Isolated and Identified from Naphtha Storage Tanks and Transporting Pipelines in Venezuelan Oil Facilities

Biocorrosion, as well as the biodeterioration of crude oil and its derivatives, is one of the major environmental, operational and economic problems in the Venezuelan oil industry. Fungal contaminants are able to produce large quantities of biomass and synthesize peroxides and organic acids, causing severe damage on metal surfaces and promoting the contamination and biodeterioration of fuels. No evidences regarding fungal strains have been reported to be associated to petroleum naphtha, widely used as a diluent of extra heavy crude oil (EHCO) in the exploitation processes of the Orinoco Oil Belt, the biggest proven reserve of EHCO worldwide. The aims of this paper were to isolate and identify fungal strains from the naphtha storage tank and the naphtha distribution network from an oil field operator in Venezuela. The results showed the isolation of four different fungal strains. The molecular identification by 28S rRNA sequencing and phylogenetic tree analysis allowed us to identify the presence of: 1) a new uncultured Ascomycota fungus species BM-103, with high identity to novel hyphomycetes Noosia banksiae and Sporidesmium tengii, in the naphtha storage tank;2) two yeasts, Rhodotorula mucilaginosa BM-104 (Phylum Basidiomycota) and Wickerhamia sp. BM-105 (Phylum Ascomycota), in a highly damaged naphtha pipeline branch and;3) Cladosporium cladosporioides BM-102 (Phylum Ascomycota) in a cluster oil well. DNA fingerprinting analysis using ERIC-PCR primers pairs also allowed us to detect the presence of R. mucilaginosa BM-104 right in the access of the studied naphtha system. Interestingly, R. mucilaginosa and C. cladosporioides were previously reported as predominant fungal contaminants of diesel and jet fuel and of kerosene and fuel storage systems, respectively. This paper represents the first evidence of fungal strains isolated and identified from the naphtha systems in the Venezuelan oil industry. The results obtained are discussed.

Study of Oil/Water Interfacial Tension of Vacuum Residual Fractions from Iranian Light Crude Oil

The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.

Migration Fractionation of Neutral Nitrogen Compounds of Crude Oils from Tabei Oilfield in the Tarim Basin, China

The absolute amounts and relative distributions of neutral nitrogen compounds in the Tabei oilfield (e.g. blocks Ln1-Ln11) showed remarkable migration fractionation in the vertical direction. From Ordovician reservoirs (O) to oil legs T-Ⅲ and T-Ⅰ of Triassic reservoirs in blocks LN1-LN11, the concentrations of + decreased from {1.59}μg/g, {0.49}μg/g to {0.17}μg/g (oil). The ratios of various alkylcarbazole isomers, such as 1,8-dimethylcarbazole/nitrogen-partially shielded isomers and 1,8-dimethylcarbazole/nitrogen-exposed isomers, were adopted as the indicators of petroleum migration. The ratios increased from {0.13}, {0.20} to {0.67} and from {0.42}, {0.87} to {3.30}, corresponding to those of Ordovician oil leg and oil legs T-Ⅲ and T-Ⅰ. In going from the south to the north of the Tabei oilfield, the absolute concentrations of neutral nitrogen compounds decreased drastically, and the nitrogen-shielded isomers were enriched relative to nitrogen-exposed isomers and nitrogen-partially shielded isomers. Crude oils in the Tabei oilfield migrated laterally from the Jilake structure to the Sangtamu fault uplift and Lunnan fault uplift, and crude oils in the same fault uplift migrated and remigrated vertically from Ordovician reservoirs, to oil legs T-Ⅲ to T-Ⅰ of Triassic reservoirs.

Biomarker responses in the bivalve Chlamys farreri to the water-soluble fraction of crude oil

To investigate the effect of the water soluble fraction of crude oil(WSF) on marine bivalves, the scallop C hlamys farreri was exposed to three WSF concentrations(0.18 mg/L, 0.32 mg/L, and 0.51 mg/L, respectively) in seawater. Petroleum hydrocarbon contents in scallops and a suite of enzymes [7-Ethoxyresorufin-O-deethylase(EROD), aryl hydrocarbon hydroxylase(AHH), glutathione S-transferase(GST), and glutathione peroxidase(GPx)] in gills and digestive glands were monitored over 10 days. The results revealed that WSF affected the activity of the four enzymes in the gills and digestive glands. EROD activity in the gills was significantly induced in most individuals of the three test groups, while in the digestive gland it was significantly induced in the low-concentration group within 4 days but was inhibited in the middle- and high-concentration groups on days 1, 4, and 10. AHH activity in the gills of all treatment groups was significantly induced on day 1. In the digestive gland, AHH activity was induced in most individuals from the treatment groups. In all treatment groups, GST activity was significantly inhibited from days 2 to 10 in the gills and was induced after day 4 in the digestive gland. GPx activity in the gills was significantly inhibited throughout the exposure period in all treatment groups. There was no overall significant difference in GPx activity in the digestive gland between the control and treatment groups. Our results also revealed that petroleum hydrocarbon concentrations in the tissues increased linearly with exposure time. EROD activity in the digestive gland and GST and GPx activity in the gill tissue were negatively correlated with petroleum hydrocarbon body burden. These enzymes play important roles in detoxification and can act as potential biomarkers for monitoring petroleum hydrocarbon contaminants in the marine environment.

Forecasting on Crude Palm Oil Prices Using Artificial Intelligence Approaches

An accurate prediction of crude palm oil (CPO) prices is important especially when investors deal with ever-increasing risks and uncertainties in the future. Therefore, the applicability of the forecasting approaches in predicting the CPO prices is becoming the matter into concerns. In this study, two artificial intelligence approaches, has been used namely artificial neural network (ANN) and adaptive neuro fuzzy inference system (ANFIS). We employed in-sample forecasting on daily free-on-board CPO prices in Malaysia and the series data stretching from a period of January first, 2004 to the end of December 2011. The predictability power of the artificial intelligence approaches was also made in regard with the statistical forecasting approach such as the autoregressive fractionally integrated moving average (ARFIMA) model. The general findings demonstrated that the ANN model is superior compared to the ANFIS and ARFIMA models in predicting the CPO prices.

GEANT4 simulation of water volume fraction measurement in dehydrated crude oil

Online measurement of water volume fraction (WVF) in dehydrated crude oil is a difficult task due to very little water in dehydrated crude oil and high precision requirements. We presents a method to measure water volume fraction in dehydrated crude oil with γ-ray densitometry. The Monte Carlo computer simulation packet GEANT4 was used to analyze the WVF measuring sensitivity of the γ-ray densitometry at different γ-ray energies, and effects of temperature, pressure, salinity and oil components on WVF measurement. The results show that the γ-ray densitometry has high sensitivity in γ-ray energy ranges of 16~25keV, and it can distinguish WVF changes of 0.0005. The calculated WVF decreases about 0.0002 with 1℃ of temperature increase and they have approximately linear relation with temperature when water volume fraction remains the same. Effects of pressure, salinity and oil components on water volume fraction can be neglected. Experiments were done to analyze sensitivity of the γ-ray densitometry. The results , as compared with simulations, demonstrate that simulation method is reliable and it is feasible to gauge low water volume fraction using low energy γ-rays.

原油直接催化裂解UPC工艺过程模拟与反应参数多目标优化

原油直接催化裂解技术可以实现从原油到三烯(乙烯、丙烯、丁烯)、三苯(苯、甲苯、二甲苯)的一步跨越,对我国炼化行业的转型升级具有重要意义。以全馏分石蜡基中原原油(159~780℃)为原料,采用混合馏分结构与分子组成集总建模策略,对原油直接催化裂解制烯烃(UPC)反应过程进行建模与工艺参数校准,并基于工业试验数据验证了其准确性。以多产烯烃、控制焦炭生成为目的,利用NSGA-Ⅲ多目标优化算法对模型进行了优化,得到优化后的操作参数。采用优化后的操作参数,即在第一段预热闪蒸温度为194.32℃、第二段预热闪蒸温度为228.16℃、第一段提升管反应器出口温度为615.73℃、第二段提升管反应器出口温度为622.59℃的条件下,UPC工艺得到的乙烯和丙烯收率之和为53.367%,焦炭收率为8.311%。此外,由于现行税费体系燃料型工艺路线税收贡献明显高于化工型工艺路线,UPC工艺参数优化后,烯烃收率大幅度提升,燃料油收率大幅度下降,原油生产总值降低44.30元t。

Phase-Controlled and Gas-Washing Fractionations During the Formation of Petroleum Reservoirs

By PVT fractionation experiments to model phase\|controlled and gas\|washing fractionations during the formation of petroleum reservoirs, the authors measured the physical and chemical properties of products formed in different fractionation stages and made a correlative analysis of the influence of depressurization and gas washing on oil/gas molecular composition and the rule of fractionation. The analytical results showed that gas washing is an important factor affecting the physical properties of crude oils, and also can be regarded as a good genetic interpretation of marine wax\|high oils in the Tarim region, Xinjiang, China. Phase\|controlled and gas\|washing fractionations can lead to the formation of condensates and their differences in chemical composition from crude oils are a direct reflection of evaporating fractionation. Phase\|controlled and gas\|washing fractionations have a great influence on the composition of molecular compounds and relevant parameters. So phase\|controlled and gas\|washing fractionations during the formation of petroleum reservoirs are not only favorable to identifying different processes of formation of petroleum reservoirs, but also to the scientific application of routine geochemical parameters.

碳同位素分馏效应对深层原油来源判识的影响

深层烃源岩演化程度高,随成熟度升高,原油中生物标志化合物含量大幅度减少,影响了利用常规生物标志化合物参数进行油源对比的可靠性。针对如何更好地利用δ^(13)C_(PDB)值进行深层原油来源判识,通过渤海湾盆地济阳坳陷东营凹陷烃源岩自然演化剖面中可溶有机质、烃源岩生排烃物理模拟实验产物4种族组分δ^(13)C_(PDB)值的分析,结合烷烃质量分数特征,探讨了深层烃源岩原油碳同位素分馏效应,提出利用δ^(13)C_(PDB)值进行深层原油来源判识的工作思路和方法。深层烃源岩因高热演化程度而产生的碳同位素分馏效应是明显的,烃源岩可溶有机质的烷烃、芳烃、非烃和沥青质4种族组分δ^(13)C_(PDB)值随埋深的增加均发生了明显增大现象,其中烷烃δ^(13)C_(PDB)值变化最明显,达5‰以上,芳烃δ^(13)C_(PDB)值约为4‰,非烃和沥青质δ^(13)C_(PDB)的变化相对较小,约为2‰~3‰。随埋深的增加可溶有机质中烷烃质量分数由40%左右增至80%以上,相应烷烃δ^(13)C_(PDB)值由-30‰左右增至-24‰以上,且烷烃质量分数与其δ^(13)C_(PDB)值的变化有很好相关性。同一类型烃源岩样品生排烃物理模拟产物族组分δ^(13)C_(PDB)值也显示了相似的结果,烷烃δ^(13)C_(PDB)值的变化幅度最大可达4‰,而芳烃、非烃、沥青质的δ^(13)C_(PDB)值变化相对较小,约为1‰~3‰。利用碳同位素进行深层原油来源判识时,首先根据烷烃质量分数与烷烃δ^(13)C_(PDB)值的相关性判断是否存在热演化造成的碳同位素分馏效应,并对烷烃δ^(13)C_(PDB)值进行合理恢复,然后再利用恢复后的δ^(13)C_(PDB)值进行原油来源的合理判识。依照上述方法对准噶尔盆地西缘车排子凸起轻质油来源进行了判识,轻质油的碳同位素明显存在热演化造成的分馏效应,轻质油源自深部二叠系高成熟烃源岩的可能性很大,这对该地区油气勘探目标评价部署工作具有重要实践意义。

原油组分Re-Os放射性同位素体系特征及其定年机理与应用启示

Re-Os放射性同位素体系可用于含油气系统关键地质过程的定年与示踪研究。不过,Re-Os定年的精度仍受到有关科学问题的制约,如原油组分的Re-Os体系特征、沥青质渐进散失对原油Re-Os体系特征与定年应用的影响等。本研究通过二元溶液直接分离原油次组分的实验,揭示了原油组分的Re-Os体系特征,模拟了实际地质情况中沥青质渐进散失对原油Re-Os体系特征与定年应用的影响,并通过重复实验验证相关实验流程对所取得的结果和认识的影响。研究发现,根据沉淀的先后顺序,原油次组分的Re和Os元素丰度总体上呈下降趋势,但有起伏变化,Re-Os同位素比值则单调下降。因此,沥青质的渐进散失将导致原油Re和Os元素丰度以及Re-Os同位素比值降低,进而对原油和低成熟度沥青Re-Os定年与示踪的应用产生影响。重复实验表明,实验室分离次组分的操作结果具有一定的随机性,但不影响Re-Os体系的总体性质。

常减压直馏煤油转产石脑油的工业实践

Z炼油厂航煤生产能力受内外贸市场需求变弱的影响,出现产品产量过剩,需要将过剩航煤转化为其他高价值产品,但由于航煤调入柴油过多会导致柴油闪点及十六烷值不合格,需要寻找解决过剩航煤新思路。利用工艺操作调整将常减压常一线航煤终馏点由243℃降至210℃,投用常二线柴油汽提蒸汽,提高混合柴油闪点,确保柴油闪点符合质量指标要求,同时掺炼中间-石蜡基原油提高常一线煤油的烷烃含量,利用技改技措新增管线将航煤改至石脑油罐区与加氢石脑油等馏分调和作为乙烯裂解原料。该工业实践表明:通过常减压常一线航煤终馏点及原油加工比例调整,可以将航煤转产符合乙烯蒸汽裂解质量要求的石脑油。本次航煤转产石脑油,共计实现将11.14×10^(4)t煤油转产石脑油,较直接调入柴油合计增效4319.53万元。常一线航煤转产石脑油不但可以有效化解航煤产量过剩问题,而且可以避免大量调入柴油带来的质量问题,同时提升企业效益。

进口俄罗斯原油综合性质评价

使用实沸点蒸馏仪对进口俄罗斯原油进行切割,分析所得馏分,并与已知性质的陕西榆林地区原油作对比,得出进口俄罗斯原油综合评价数据。结果表明:与榆林原油相比,进口俄罗斯原油的轻油馏分收率较高,按关键馏分分类属于中间基原油;15~175℃馏分精制后是高品质的乙烯裂解原料,65~175℃馏分可作催化重整原料,140~240℃馏分可生产3号喷气燃料;175~370℃馏分可生产-20号车用柴油,240~360℃馏分可生产-10号车用柴油,360~500℃馏分经脱蜡、精制后,可生产对黏度指数要求不高的润滑油基础油原料,360~540℃馏分是一般的催化裂化原料;>360℃重油馏分属于二类渣油,可部分掺入蜡油中用作催化裂化原料,>540℃渣油馏分属于三类渣油,可用作延迟焦化原料。

重油MIP-CGP装置加工俄罗斯原油常三线馏分

在中国石油大庆石化公司2.0 Mt/a重油多产异构烷烃并增产丙烯的催化裂化(MIP-CGP)装置上,进行了加工俄罗斯原油常三线馏分(以下简称常三线)催化裂化转化生产液化气和汽油的工业应用,旨在降低柴汽比。结果表明:当常三线在重油MIP-CGP装置混合加工原料中的质量占比为15.45%时,产物中干气、油浆、焦炭收率较加工常三线前依次下降了0.03,0.02,0.20个百分点;而液化气、汽油、柴油收率依次上升了0.19,0.05,0.01个百分点;常三线的裂化反应表观转化率高达81.13%,液化气、汽油的表观收率分别为25.86%,37.63%;液化气、稳定汽油、轻柴油的性质均较加工前变化不大。

管道中重质原油流变特性及流动传热规律

因重质原油流动过程存在历史记忆性和全域相关性,经典牛顿本构模型无法有效刻画其流变特性。建立了能够有效刻画重质原油流变特性的空间分数阶本构模型,并基于有限元法数值模拟了原油流动与传热过程。主要研究了空间分数阶模型阶数对原油流动与传热的影响,分析了平均努塞尔数与摩擦阻力系数随着分数阶阶数的变化规律;并比较了管壁热边界条件分别为常壁温与壁面热流密度下,原油传热过程中局部努塞尔数和对流换热系数的变化情况。研究结果表明:随阶数α(α>1)的增大,原油流变性能逐渐向剪切变稀转变,加快了原油流动速度,同时原油传热性能增强,有助于原油的输运效率增加。此外,在壁面热通量条件下的传热效率高于常壁温条件下的传热效率。因此深入研究原油的流变特性以及流动与传热规律,可为提高管道原油输运效率与经济运行提供理论指导。

原油水溶性成分对黑苦荞种子萌发及幼苗生理指标的影响

水是植物生长必不可少的因子,石油开发区水环境受到的污染将会对植物生长造成威胁。本研究发现,不同浓度原油水溶性成分对黑苦荞种子萌发及幼苗生长的影响差异显著。原油水溶性成分浓度从0%提高到6%时,胚轴长、根长、发芽率均逐渐升高;而在6%到20%的浓度下,以上指标均呈下降趋势;黑苦荞幼苗中总蛋白质含量、丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性及脯氨酸(Pro)含量在不同浓度原油水溶性成分的胁迫下变化趋势不同,蛋白质含量随原油水溶性成分浓度的增加总体趋势表现为下降,MDA含量、SOD活性和Pro含量随着原油水溶性成分浓度的升高呈上升趋势且SOD活性和Pro含量上升较为缓慢。本研究初步探讨了原油水溶性成分对荞麦种子萌发及幼苗生长的影响,为研究原油污染水质对陇东地区荞麦产量和品质的影响奠定了基础。

胜利原油各组分对界面膜扩张流变性的影响

采取经典的四组分分离方法(SARA)将胜利原油分离得到饱和分、芳香分、胶质和沥青质,利用醇碱萃取法得到酸性组分。通过滴外形分析方法系统研究了上述5类原油组分及稀释原油的界面扩张流变性质,考察了振荡频率和各组分质量分数的影响。结果表明,各类活性组分及稀释原油表现出与表面活性剂类似的界面扩张行为,扩张模量均随振荡频率增大而增大,随质量分数的增加先增大后减小;相角随振荡频率增大而降低,随质量分数增大而增加。各组分模拟油及稀释原油形成的界面膜均表现出较强的弹性行为,且按其界面行为可以分为3组:稀释原油和饱和分、酸性组分和胶质、芳香分和沥青质。模量最大值对应的质量分数高低顺序为稀释原油和饱和分、酸性组分和胶质、芳香分和沥青质。沥青质扩张模量的最大值在25mN/m左右,略高于稀释原油和其它活性组分。

原油活性组分油水界面膜扩张粘弹性研究

研究了用超临界萃取分馏法(SFEF)从伊朗重质原油中分离的两个具有不同平均分子量的原油界面活性组分在正癸烷/水界面的扩张粘弹性行为以及温度对体系扩张粘弹性的影响.研究发现平均分子量大的样品能在油水界面形成更为牢固的界面膜.从扩张模量幅度对扩张频率的双对数曲线和扩张模量相角的频率依赖关系可以推断所有实验体系界面膜的主要的弛豫过程不是扩散弛豫,而可能主要是通过吸脱附势垒的弛豫过程.温度对两个样品的扩张粘弹性参数都有强烈的影响.升高温度可以降低膜的强度和粘度,并且改变相角的频率响应.

大庆原油活性组分及相关界面性质

用沉淀法和色谱分离法将大庆原油分离成沥青质、极性物和抽余油 3部分。傅立叶红外光谱分析表明 ,沥青质组分和极性物中存在羧酸类或酚类以及含氮化合物 ,抽余油主要为烃类物质 ,可能还存在很少量的非极性基团较大的酯类物质。测定结果表明 ,在大庆原油中 ,沥青质的相对分子质量最大 ,其次为极性物 ,抽余油的相对分子质量最小。沥青质、极性物和抽余油都具有一定的界面活性。原油乳化实验表明 ,沥青质具有较弱的W /O乳化能力 ,抽余油具有较强的W /O乳化能力 ,是造成大庆原油W /O乳化的主要组分 ,极性物是造成大庆原油O/W乳化的主要组分。