Studies on Nigerian Crudes. I. Characterization of Crude Oil Mixtures

Nigerian crude oil samples produced from various locations have been tested under laboratory conditions using ASTM methods. Experimental analyses were performed on fifteen light and medium pure samples and their binary mixtures. Observations showed that oils characterized by the same specific gravity do not exhibit the same viscosity. Both gravity and viscosity increased with volume concentration in a nonlinear manner. Only binary blends of light crude oils produce linear viscosity-composition relationship. The viscosity-composition data for other blends were correlated using double logarithmic plots. These plots indicate that medium/medium crude oil blends demonstrated very clear linearity over the entire composition range while light/medium mixture plots were linear in the 0-50 vol.% composition range. Viscosity has been found to be a very useful parameter for correlating the properties of crude oil mixtures.     

微量元素在霸县凹陷油源对比中的应用

作者用发射光谱测定了冀中坳陷霸县凹陷下第三系、石炭二叠系和奥陶系6个层位75个原油样和360个生油岩样的18种微量元素的丰度,计算了14个丰度比值。根据这些资料,用聚类分析法进行了油-油对比,又用判别分析法建立了各层系生油岩的判别函数式,再用二级判别分析法进行了油-岩对比。判别结果:第三系原油来自下第三系母岩;石炭二叠系凝析油及轻质油来自石炭二叠纪煤系,属于煤成油;奥陶系原油一部分来自下第三系母岩,另一部分轻质油来自石炭二叠系母岩。     

Evaluation of Trace Metals and Physical Properties of Nigerian Crude Oil Saturate Fraction

Analyses of trace elements and physical properties of the saturate fraction of Nigerian crude oil were done in order to establish the characteristics that may aid the developmental processes of the natural resources. Crude oil samples were collected from three different oil fields in Niger-Delta area of Nigeria. The saturate fractions were eluted by column chromatography using n-hexane. The saturate fractions were investigated for functional groups using Fourier transform infrared spectrometry (FT–IR); the elemental concentrations were determined using Atomic absorption spectrometry, while the physical properties (flash point, ash content, refractive index, and color) were determined using standard analytical methods. The results revealed that the infrared spectra of the saturate fraction of the Nigerian crude oil showed mainly the presence of C-H(CH₃) and C-H(CH₂) functional groups, indicating high purity of the samples. The concentrations of the analyzed elements (Mn, Cu, Co, Zn, Fe, V, Cr, and Ni) in the saturate fraction were generally low compared to other fractions of Nigerian crude oil. This study revealed that Co has the highest mean concentration of 1.81 ± 0.36 mg/L, while Mn has the lowest mean concentration of 0.04 ± 0.02 mg/L. The t test values for the comparison of the elemental concentrations of Nigerian crude oil /saturate fraction and crude oil asphaltene/saturate fraction showed significant difference (except Mn) with respect to Nigerian crude oil /saturate fraction. The cluster analysis for the elements showed two groups, which are fairly well correlated indicating similar source and similar chemical affinity. The cross-plot analysis of the Nigerian crude oil and its saturate using elemental concentrations as the variables showed a strong positive inter element correlation since (R² = 0.71), establishing a relationship between the Nigerian crude oil and the saturate fraction. The color of the saturate fraction ranged from off-white to colorless. The results of analysis provide useful information on its conversion mechanism and environmental implications of the development of the fossil fuel deposit.     

C4-C8轻烃在原油地球化学研究中的应用——以塔里木盆地大宛齐油田凝析油为例

全油样品的GC分析表明,塔里木盆地大宛齐油田不同层位的81个原油样品富含轻烃组分,且部分样品遭受了不同程度的微生物降解。以C₄-C₈轻烃地球化学参数为工具,对原油成熟度和次生蚀变等方面进行地球化学研究。轻烃成熟度参数表明,原油的折算R_c在0.9%左右,处于成熟阶段。对遭受生物降解作用的原油分析发现,随着生物降解作用的增强,其Mango轻烃参数K₁值减小,K₂值明显增大,甲基环己烷指数增大,甲基环戊烷较乙基环戊烷更容易遭受生物降解,表明单烷基环戊烷中烷基取代基越大的烃类越难遭受生物降解作用。结合轻烃参数指示的原油成熟度和母质来源,推测研究区原油为次生凝析油。通过轻烃参数对比研究发现,大宛齐油田凝析油轻烃参数特征与大北和其南部地区正常原油相似。依据塔里木盆地大宛齐油田的地质背景和原油成藏模式可知,研究区原油是大北和南部地区两类原油通过深大断裂运移到大宛齐浅部,通过蒸发分馏作用聚集成藏。      

渤海湾盆地渤中凹陷渤中19-6构造凝析油气特征与形成机制

基于凝析油和天然气组分、生物标志化合物、稳定碳同位素和储层流体包裹体等分析结果,综合运用多种油气地球化学方法,明确了渤海湾盆地渤中凹陷西南部渤中19-6构造中凝析油和天然气的特征及成因,探讨了油气的形成机制。研究结果表明,渤中19-6构造的凝析油具有低密度、低黏度、低胶质+沥青质、高蜡和高凝固点的物性特征,其正构烷烃以中—高碳数为主,轻烃组分以正辛烷、正庚烷和甲基环己烷为主且含量相当,为沙河街组三段烃源岩成熟阶段的产物。天然气组分主要为烃类气,非烃气体含量低,为沙河街组三段偏腐殖型烃源岩裂解气。12 Ma以来,渤中19-6构造经历了重质油、轻质油气、凝析油气和天然气的多幕连续充注。相控混溶为渤中19-6构造中凝析气的主要形成机制,即在含原油的天然气流体中,当地下温度、压力升高时,早期原油溶于晚期充注的天然气中,形成现今的凝析气藏。     

黄骅坳陷千米桥古潜山构造凝析油气藏的油源研究

对千米桥古潜山高蜡凝析油C12 —C35 液态烃馏分进行精细的化学组成剖析 ,是开展准确的油源研究之基础。原油地球化学特征分析表明 ,受凝析油形成过程中的化合物分馏效应影响 ,常规甾、萜烷含量甚微且分布面貌已不同程度失真 ;凝析油具有相对富集的重排补身烷和较高的苯并 [e]芘及单峰的系列等特征性分布指纹 ,可以作为油源研究的基础。单体烃碳同位素、馏分碳同位素等的油 油对比表明 ,板深 4、7、8井奥陶系凝析油与板深 35井沙三段轻质油等第三系原油具有可比性 ,应为同源产物 ;无论是馏分碳同位素、单体烃碳同位素还是生物标志物等的油 岩对比均表明 ,板深 4、7、8井奥陶系凝析油与板深 7井、板深 35井沙三段泥岩具有母源成因联系 ,沙三段是千米桥古潜山油藏的油源层。图 5表 4参 1 5     

用乙烷作为岩屑荧光录井替代试剂的探讨

Cuttingsfluorologgingisasimple,straightforward,practicalandeffectivemethodwhichiswidelyusedinoilexplorationtopreliminarilylocatethepayzone.ItisofparamountimportancelnguidingexpIorationoperationtocorrectlydeterminewhetherthecuttingsisfluorescentandthegradi…     

Chemometric representation of molecular marker data of some Niger Delta crude oils

Chemometric representation of data is the most preferred and adopted method of research reporting in contemporary times. Data are easily discerned and interpreted. Molecular maker parameters of some crude oils from the Nigerian’s Delta region are chemometrically expressed after data treatment using multivariate statistical analyses, other graphical representations were the star diagram and triangular (ternary) plot. The results indicated discrimination of samples into two genetic families corresponding to their primary oil fields. These groupings were more obvious for results obtained via principal component analysis. Genetic groupings are principally due to compositional differences which are commonly attributed to unique source rock depositional environments and/or sourcing organic matter. The two families of oils identified have both terrestrial inputs, but differ comparatively by relative marine inputs.     

吐哈油田轻质原油族组分分析方法的建立及应用

现行的原油族组分分析行业标准仅适合于正常原油和稠油,却不适合密度低、挥发性强的轻质原油(含凝析油),但轻质原油族组分分析需求却是客观存在的.通过反复地试验对比,应用液固吸附柱顶替色谱法,建立了一套适合吐哈油田轻质原油的族组分分析方法,实际应用后效果良好,并应用该方法分析了一批国外合作区块的轻质原油样品,结果准确、可靠,...     

海相古油藏及可溶有机质再生烃气能力研究

通过大量样品的封闭体系热压模拟实验,对比研究了不同性质、不同组成海相古油藏及可溶有机质热裂解再生烃(气)能力及其产率分布特征。结果表明,不同海相古油藏与可溶有机质的再生烃气能力大小为:凝析油>轻质油>正常原油>志留系沥青砂岩≥稠油≥低成熟固体沥青≥含沥青灰岩>稠油油砂>氧化固体沥青;其再生烃气能力除与岩性、赋存状态、演化程度等有关外,主要受所含可溶有机质性质和组成的制约;可溶有机质再生烃过程是干酪根生烃的延续,其生烃气潜力与干酪根烃源岩相当,当其达到高过成熟阶段时,可以作为新的轻质油气或者天然气来源。      

东海西湖凹陷平湖构造带油气分布规律

平湖构造带有正常凝析油、非正常凝析油、轻质原油和正常原油4种类型原油。天然气以热解成因的凝析气为主。平湖构造带产出的油气以凝析气为主,原油次之。花港组油气藏以背斜型油藏为主,并多被断层所切割;平湖组油气藏依附于断裂,多为受同生断层控制的断块和半背斜凝析气藏。     

Optimum demulsifier formulations for Nigerian crude oil-water emulsions

The formation of crude emulsion during oil production and processing is a challenge of significant proportions to the oil producers. Studies show that about two third of Nigerian crude oil production is in form of water in oil emulsion. For economic and operational reasons, it is necessary to separate the water completely from the crude oil before transportation or refining.Efficiency of separation of crude emulsions is of major importance to producers. To this end, this study primarily seeks to investigate the formulation of effective demulsifier that can be used to achieve this aim; and in so doing, the optimal separation efficiency attainable by this demulsification process is determined. Six different samples of water and oil soluble demulsifiers were used on two different samples of synthetic emulsion (sample I and II (both water in oil emulsion) from different Nigerian oil fields). The bottle test method was used to determine the percentage water separation for each crude oil emulsion/chemicals (demulsifiers) mixture. The concentrations of the combined six chemicals (demulsifier samples A–F) in the mixture were related to the percentage water separation using response surface methodology central composite design (RSMCCD).Results show that the optimum concentrations of demulsifiers A–F are 59?ppm/39?ppm/29?ppm/20?ppm/29?ppm/13?ppm respectively for crude oil sample I. While 54?ppm/40?ppm/25?ppm/21?ppm/29?ppm/8?ppm respectively were observed as optimum concentration for crude oil II. The combination of these chemical was observed to return better performance than the existing commercial demulsifiers with percentage water separation of 92% and 94% compared to percentage water separation of 87% and 90% returned by one of the currently available demulsifier used in the petroleum industry for crude oil A and B respectively. Hence, the need to carry out optimization analyses on different emulsified crude oil cannot be over-emphasize.     

原油单萜烃的分布及地球化学意义

应用全二维气相色谱-飞行时间质谱(GC×GC-TOFMS)对采集自塔里木、北部湾、准噶尔、琼东南及江汉盆地的共45件原油样品进行分析。借助标准样品对原油中18个C₁₀化合物进行定性定量,其中包括2,6-二甲基辛烷(2,6-DMO)、2-甲基-3-乙基庚烷(2-M-3-EH)、1,1,2,3-四甲基环己烷、反-1-甲基-4-异丙基环己烷、1-甲基-3-异丙基苯和1-甲基-4-异丙基苯6种单萜烃化合物。研究表明,原油样品中均存在丰度不等的6种单萜化合物。高等植物精油催化加氢产物中检测到丰富的单萜烃,表明陆生高等植物为单萜烃的可能来源之一。新分子标志物参数2-M-3-EH/2,6-DMO(MTR)与Pristane/Phytane(Pr/Ph)相结合可以有效区分源自不同沉积环境源岩的原油样品:源于偏还原沉积环境源岩的原油具有较高的MTR和较低的Pr/Ph值,而源于偏氧化沉积环境源岩的原油则具有较低的MTR和较高的Pr/Ph值。定量数据表明,两类原油中MTR和Pr/Ph值的差异源于原油中2-M-3-EH及Phytane含量的差异,即两类原油样品中2,6-DMO和Pristane的含量范围十分相似,而2-M-3-EH及Phytane的含量范围则差异明显。偏还原环境下沉积的源岩所生成的原油中2-M-3-EH和Phytane的含量相对较高,而偏氧化条件下沉积的源岩所生成的原油中两者含量则相对较低。MTR可以与Pr/Ph一起用于判断源岩沉积环境的氧化还原程度,其对于生标含量很低或匮乏的轻质油及凝析油十分重要。     

Studies on Nigerian Crudes IV. Improvement of Asphaltic Properties of Residual Asphalts

Residual asphalts obtained from 25 samples of Nigerian light, medium, and heavy crude oils were chemically treated by air-oxidation and sulfurization to improve their characteristic properties. The asphalt yield for light crudes varied from 27.7-33.7 wt% and 33.4-67.5 wt% for medium crudes. The chemical treatment brought about changes in chemical composition, increase in molecular mass and modification of consistency resulting in highly improved asphaltic properties. There were manifold increases in viscosity and softening points, which came as a result of the higher asphaltene content of the treated materials. The asphalts obtained meet quality specifications for typical commercial grade products thus confirming the suitability of Nigerian crude oils for the production of residual asphalts.     

Gasoline- and diesel-like products from heavy oils via catalytic pyrolysis

Heavy oil is less expensive than light crude oil, but heavy oil is more expensive to obtain light oil products. Conventional light crude oil resources are decreasing, therefore heavy oil resources will be needed more in the future. There are huge differences from field to field for heavy oil deposits. In terms of final productive use, heavy oil is considered as an unconventional resource. Heavy oil upgrading depends on four important factors: catalyst selection, heavy oil classification, process design, and production economics. Heavy and extra-heavy oils are unconventional reservoirs of oil. Globally, 21.3% of total oil reserves are heavy oil. Heavy oil is composed of long chain organic molecules called heavy hydrocarbons. The thermal degradation of the heavy hydrocarbons in heavy oil generates liquid and gaseous products. All kinds of heavy oils contain asphaltenes, and therefore are considered to be very dense material. The most similar technologies for upgrading of heavy oils are pyrolysis and catalytic pyrolysis, thermal and catalytic cracking, and hydrocracking. The amount of liquid products obtained from pyrolysis of heavy oil was dependent on the temperature and the catalyst. Pyrolytic oil contains highly valuable light hydrocarbons as gasoline and diesel components range. The constant increase in the use of crude oils has raised prices of the most common commercial conventional products and consequently seeking for new alternative petroleum resources, like some unconventional oil resources, becomes an interesting issue. The mass contents of gasoline, diesel, and heavy oil in the crude oil are 44.6%, 38.3%, and 17.1%, respectively. The gasoline yield from the heavy oil catalytic (Na₂CO₃) pyrolysis is higher than the diesel efficiency for all conditions. The yield of gasoline products increases with increasing pyrolysis temperature (from 230°C to 350°C) and percentage of catalyst (from 5% to 10%). The yields of gasoline-like product are from 21.5% to 39.1% in 5% catalytic run and from 32.5% to 42.5% in 10% catalytic run. The yields of diesel-like product are from 9.3% to 29.8% in 5% catalytic run and from 15.5% to 33.7% in 10% catalytic run.     

库车前陆盆地玉东地区白垩系油气成藏过程

利用流体包裹体岩相学观察和显微测温、定量荧光分析和盆地模拟技术,研究了库车前陆盆地玉东地区白垩系储集层油气成藏过程。结果表明,玉东地区经历了晚期油、气充注和后期调整富集。其成藏过程：①来自库车坳陷中侏罗统的湖相原油在距今4 Ma时充注到玉东地区下白垩统储集层,充注量较少,形成的轻质油包裹体丰度较低,黄色荧光轻质油包裹体记录了该期原油充注;②来自库车坳陷中-下侏罗统的煤型天然气在距今3.5 Ma时充注进来,天然气对早期原油气洗,轻质组分溶解到天然气中形成次生凝析气,重质组分和沥青质富集残留,蓝白色荧光油包裹体和气烃包裹体记录了该期天然气充注;③随着天然气持续充注和库车组沉积晚期构造抬升,天然气与早期原油发生混合作用的同时,在浮力驱动下,向上运移,并在古近系膏泥岩盖层之下富集成藏,形成凝析气藏。现今气水界面位于深度为4 776 m处,该界面之下形成以凝析油、重质油和沥青质为主的残余油藏,残余油水界面位于深度4 798.5 m处,但残余油饱和度较低。     

原油轻烃反吹色谱分析

利用程序升温进样(PTV)和切割反吹色谱分析技术对原油C₁₅及以前的轻烃组分分析方法进行了研究。通过对压力(P₁,P₂)、变压时间和变压速率等进行优化选择,在切除中—重质烃类物质、保护分析柱的同时实现了轻烃组分的快速分离分析,几个难分离物质对的分离度都优于GB/T18430.1—2001和美国1998ASTM:D5134—98的要求,分析结果稳定可靠,轻烃指纹参数和正常色谱分析结果有很好的可比性。应用此方法对准噶尔盆地部分原油样品进行了分析,轻烃地球化学参数特征清晰地反映了油样的同源性和运移方向。      

Gasoline production in stabilization of feedstock in hydrocyclones

Fundamentally new technology for production of gasoline in stabilization of crude oil and gas condensate in a centrifugal force field is directed toward increasing the intensity of the process and decreasing capital and power costs. By regulating the pressure and temperature at the inlet into the hydrocyclone, it is possible to control production of unstable gasoline. By-products of petrochemistry are used to increase its octane number. Synergism in improving the quality of the gasoline in multistage hydrocycloning of crude and incorporation of oxygen-containing components was demonstrated. __________ Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 1, pp. 6–9, January–February, 2006.