OCCURRENCE AND DISTRIBUTION OF n-ALKANESAND n-FATTY ACIDS IN SAUDI ARABIAN CRUDE OILS

Ten crude oil samples, covering wide range of maturity (API gravity = 18·5-36·1), were assembled from Safaniya, Abqiq, Ain Dar, Wafra. Marjan and Zuluf oil fields in the area of Arabian Gulf. n-Alkanes of were separated from the petroleum distillate ((150°C-450°C) of the crude oils by urea adduction. n-Fatty acids were separated from the fraction of n-alkanes by treatment with aqueous solution of KOH. Distribution of n-alkanes and n-fatty acids has been investigated by means of gas chromatography. The studied crude oils showed symmetrical distribution curves of n-paraffins and fatty acids of low molecular weight were abundant as compared with n-paraffins. The n-paraffins distribution curve of Wafra/Iucene biodegraded immature crude oil showed three maxima at C₁₇, C₁₉, and C₃₁ whereas the maxima of n-fatty acids are located at C₁₄,C₂₂and C₂₄. The results were interpreted in terms of origin, maturation and depositional environments of the crude oils.     

ARAB LIGHT CRUDE STUDY FOCUSES ON KINEMATIC VISCOSITY

Arab light crude oil has been characterized in terms of API gravity, total sulfur content, Reid vapor pressure, ash content, heating value, salt content, viscosity SUS, vanadium content as V₂O₅, pour point and analyses of various metals. The crude oil was fractionated into six true boiling point (TBP) fractions (IBP-95°C, 95-205°C, 205-260°C, 260-345°C, 345-455°C and 455°C+). These fractions were characterized in terms of API gravity, total sulfur, H₂S, mercaptan contents, molecular weight, elemental analyses for total carbon, hydrogen and nitrogen, and analyses of various metals. The kinematic viscosity data have been obtained for 95°C+ TBP fractions for a wide range of temperature up to 200°C.     

THERMAL DECOMPOSITION OF SAUDI CRUDE OIL ASPHALTENES

Asphaltenes precipitated by the use of pentane, heptane and decane solvents from Saudi Arabian Light (AL) and Saudi Arabian Heavy (AH) crude oils 370^°C + residua have been investigated by thermal gravimetric analysis and pyrolysis - gas chromatographic analysis at 350^°C and 520^°C. Gas chromatographic analysis of the gases evolved during pyrolysis has shown that CO, CO₂ and CH₄ constitute the major portion of the gases evolved at 350^°C from pentane and heptane asphaltenes of AH residue and from pentane asphaltenes of AL residue. Whereas gases evolved from decane asphaltenes are dominated by CO₂ and C₂-C₄ hydrocarbon gases. At 520^°C, hydrogen and methane represent 56-80 vol %of the gases evolved from all the four asphaltenes. The amounts of C₁-C₄ hydrocarbon gases increased with an increase in the carbon number of the precipitating solvent at 350^°C and decreased at 520^°C. The presence of up to C₃₆ normal alkane hydrocarbon has been indicated in the maltenes produced from these asphaltenes. The loss of nitrogen from AH asphaltenes during pyrolysis remained low (1-6 wt %), whereas the losses of oxygen and sulphur ranged from 58 to 74 wt % and 10 to 29 wt %, respectively.     

ASPHALTENES IN SAUDI ARABIAN HEAVY CRUDE OIL SOLUBILITY AND MOLECULAR WEIGHTS IN HYDROCARBON SOLVENTS

The asphaltenes from Saudi Arabian Heavy crude oil residue ( 370°C+ ) were precipitated by adding n-alkane solvents ( n-C₅ to n-C ₁₀ ) to the crude oil / residue.     

原油中甾烷的生物降解模拟实验研究

通过喜氧细菌对原油的模拟生物降解实验,以及对模拟产物的饱和烃色谱—质谱分析,对原油饱和烃中规则甾烷和重排甾烷的降解作用进行了研究。研究结果显示,规则甾烷先于重排甾烷发生生物降解,甾烷降解由易到难的顺序为C₂7>C₂8>C₂9。在甾烷被大量降解前,20S/(20S+20R)(甾烷异构化作用)等生物标记化合物的成熟度指标基本无变化,但某些用于油源对比、母源和沉积环境研究的生物标记化合物参数可能会发生变化,如:规则甾烷/17α(H)-藿烷、C₂7-C₂8-C₂9甾烷、C₂7-C₂8-C₂9重排甾烷和重排甾烷/规则甾烷等。      

酒西坳陷原油地球化学特征与成熟度分类

酒西坳陷属于典型的勘探程度非常高的含油气坳陷,目前已发现的原油主要分布于青西凹陷和鸭儿峡-老君庙-石油沟构造带。这些原油绝大多数为正常密度和黏度的中-高蜡原油,只有少量为中-高蜡稠油,具有典型湖相原油的地球化学特征,全油碳同位素δ¹³C值为-32 ‰~-30 ‰,生物标志物组成总体相似,但分布特征存在一定差异,可以分为3类不同类型或成熟度原油。第1类为低成熟原油,甾烷以规则甾烷为主,没有重排甾烷;规则甾烷以ααα-20R甾烷为主,C₂₇、C₂₈、C₂₉甾烷呈不对称V型分布,C₂₉甾烷20S/（20S+20R）和ββ/（αα+ββ）值一般小于0.4;萜烷以五环萜烷为主,Ts、C₂₉Ts和C₃₀重排藿烷低,伽马蜡烷较高。第2类为中等成熟原油,Pr/Ph值一般小于1.0;甾烷也是以规则甾烷为主,没有重排甾烷,但ααα-20S和αββ甾烷明显高于第1类原油,C₂₉甾烷20S/（20S+20R）和ββ/（αα+ββ）值一般为0.40~0.55,C₂₇、C₂₈、C₂₉ ααα-20R甾烷呈不对称V型分布,C₂₇/C₂₉比值一般大于0.6;萜烷分布特征与第1类原油类似,Ts/Tm一般小于0.5;甾烷/萜烷比值基本大于1.0。第3类为高成熟原油,Pr/Ph值一般大于1.0;甾烷以规则甾烷为主,但重排甾烷明显且含量变化大,αββ甾烷明显高于ααα甾烷,C₂₉甾烷20S/（20S+20R）和ββ/（αα+ββ）值分别大于0.5和0.6,C₂₉甾烷含量明显高于C₂₇甾烷,C₂₇/C₂₉比值一般小于0.6;萜烷分布特征与前两类原油相似,但Ts、C₂₉Ts和C₃₀重排藿烷相对较高,Ts/Tm一般大于0.5,伽马蜡烷含量变化较大;甾烷/萜烷比值基本上小于1.0。     

Oxidative Dehydrogenation of Methanol on Chromium Oxide/Montmorillonite K10 Catalysts

Methanol conversion was carried out on a mesoporous material—chromia/montmorillonite K10 (MK10)—in a pulse microcatalytic system. Methanol was converted to formaldehyde and ethylene by two different mechanisms. Methanol dehydrogenation increases by increasing reaction temperature (300-400°C) and as chromia loading decrease. On the other hand, the dehydration of methanol occurs at a higher temperature (400-500°C) and as chromia loading increase, 3-18% Cr. Redox and exposed nonredox Cr³⁺ are responsible for formaldehyde formation. There is a relationship between increased C₂H₄ production and the increase of Cr⁶⁺ phase according to the acidity of chromia catalysts 34 and 76 μL tert-Butylamine/g catalyst for 3% Cr and 18% Cr, respectively. Formaldehyde formation is diffusionally controlled at high temperatures (400-500°C) and kinetically controlled at a lower reaction temperature (300-400°C), while methanol dehydration to ethylene is surface reaction controlled at 400-500°C.     

塔里木盆地塔河油田原油地球化学特征的化学计量学分析及应用

塔里木盆地塔河油田由于存在多期次原油充注导致其成因至今无法得到很好地解释。应用地球化学手段对塔河油田原油地球化学特征进行综合研究,结果显示：塔河油田奥陶系原油沉积于海相沉积环境,处于成熟—过成熟阶段,正构烷烃分布较完整、具有UCM鼓包、普遍存在25?降藿烷、伽马蜡烷含量低,C₂₉藿烷丰度高、规则甾烷呈现C₂₉>C₂₇>C₂₈分布、规则甾烷αββ构型丰度高于ααα构型等特征,表明塔河油田原油遭受过较强程度的微生物降解作用,存在至少2个期次的原油充注。利用主成分分析（PCA）和层序聚类分析（HCA）方法对原油生物标志化合物指标进行分析,将塔河油田原油分为3类：I类原油具有三环萜烷/五环萜烷、Ts/17αC₃₀藿烷、重排甾烷/规则甾烷、C₃₁/C₃₂藿烷、C₂₉/C₃₀藿烷、C₂₄/C₂₃三环萜烷、C₂₀₊₁₉/C₂₃₊₂₄三环萜烷、Ts/Tm高,Ph/nC₁₈低,正构烷烃分布完整,呈现出多期充注特征,但主要表现出早期生物降解原油的特征,早期生物降解原油的贡献高于后期充注正常原油的贡献;II类原油的nC₂₁^-/nC₂₂⁺值最低,部分样品正构烷烃缺失,UCM鼓包明显,主要代表早期经历过强烈微生物降解的原油; III类原油nC₂₁^-/nC₂₂⁺、αβC₃₁?22S/（22S+22R）、C₂₄四环/（C₂₄四环+C₂₆三环）值最高,正构烷烃受热成熟度的影响最大,高碳数正构烷烃大量热裂解导致低碳数正构烷烃相对富集,代表混合原油但正常原油的贡献较大。     

Synthesis and Evaluation of Copolymers as Pour-point Depressants

-Olefin maleic anhydride copolymers were prepared by reacting C₈ or C₁₄ olefin with maleic anhydride, then esterified with dodecyl or NAFOL 1822B alcohol, purified and characterized through average molecular weight, polydispersity index, and infrared spectroscopy. A waxy crude oil (pour point = 21°C and wax content = 18.9 wt%) was treated with the four synthesized additives as pour-point depressants and determined using x-ray diffractometer. It is found that the x-ray diffraction patterns of waxes with additives are remarkably different from those without additives. The NAFOL 1822B ester of 1-tetradecene maleic anhydride copolymer also show stronger interaction with the wax than NAFOL 1822B ester of 1-octene copolymer, dodecyl ester of 1-tetradecene maleic anhydride copolymer, and dodecy ester of 1-octene maleic anhydride copolymer. These effects can be attributed to the chain length of side hydrocarbon. The wax solubilization is a function of copolymer.     

STRUCTURAL CHARACTERIZATION OF SOLID n-PARAFFIN COMPONENTS DERIVED FROM MUKTA CRUDE OIL

The total solid paraffins (boiling 270°C+) separated from Mukta crude by urea adduction and its narrow fractions were analysed for their structural composition by proton NMR, infrared spectroscopy and gas chromatography. It has been observed that CH2/CH3 ratio in these samples varies from 7·9 to 13·8 while their average carbon number ranges from 17 to 29·6. The CH₂/CH₃ ratio and chain length of paraffins increases with increase in boiling range of the fractions.     

STUDIES ON SLUDGE FROM STORAGE TANK OF WAXY CRUDE OIL PART - I : STRUCTURE AND COMPOSITION OF DISTILLATE FRACTIONS

Tank bottom sludge from storage tanks of Bombay High crude oil deposited during ten years have been studied. The yield of the sludge is approximately 0.1% wt. of the crude oil through-put. The residue boiling above 500°C amounts to over 50%. The distillate fractions collected at 50°C intervals have been analysed extensively and compared to fractions from whole crude of same boiling range. The sludge distillate are distinctly more paraffinic in nature.     

RECOVERY OF ASPHALTENES FROM TAR SAND BY SUPERCRITICAL FLUID EXTRACTION

Many non-oil producing countries are enriched with other sources of energy, for example tar sand, oil shale, coal, biomass, and uranium, that are not fully utilized. Supercritical fluid extraction (SFE) of tar sand was carried out in a batch autoclave at different temperatures. Extracts recovered from SFE were fractionated into oils, asphaltenes, preasphaltenes and gases by solvent extraction. The highest yield) of SFE (24.3 wt % dry basis) from tar sand was obtained with n-pentane/benzene (1/1, v/v') mixture at 655 K. Comparison of the amount of n-alkanes (C1-C4) evolved at 585 K and 685 K shows that the amount of methane is significantly increased at 685 K whereas the amount of C4 alkane is reduced. At 685 K, hydrogen and methane represent 45·1 vol % of the gases evolved from the SFE. The yields of C1-C3 alkane hydrocarbons were higher for supercritical fluid extracts at 685 K as compared to those obtained at 585 K. The quantity of olefines (C₂H₄ + C₃H₆) was found between 5·1 and 10·1 vol %.     

渤海湾盆地东濮凹陷原油地球化学特征研究

对东濮凹陷文留地区原油样和油砂样进行了族组分、碳同位素、饱和烃色谱—质谱实验分析,结果表明,文留地区沙河街组原油与含油砂岩抽提物的饱和烃含量在38.3%-79.3%;原油碳同位素值分布于-27.0‰～-28.0‰,饱和烃碳同位素值在-27.4‰～-28.7‰,族组分之间的碳同位素分馏效应较小;多数样品Pr/Ph小于0.5,具有明显的植烷优势;αααC₂₉20R/20(R+S),C₂₉ββ/(αα+ββ)参数显示处于低熟状态;甾烷系列中C₂₇含量略占优势,重排甾烷含量与成熟度相关,随样品成熟度增高,重排甾烷/规则甾烷值增大,低熟油样品的重排甾烷/规则甾烷值小于0.3。分布在中央隆起带文西断层与文东断层之间地区的样品,其γ-蜡烷含量较高,γ-蜡烷/C₃₀藿烷分布于0.40～0.99,γ-蜡烷/H₃₁22S.分布于2.11～4.15,反映了陆相咸水湖相原油特征。分布于文东断层以东的原油样品γ-蜡烷含量低,γ-蜡烷/C₃₀藿烷分布于0.05～0.15,γ-蜡烷/H₃₁22S分布于0.16～0.28,反映了低盐度的淡水—微咸水相原油特征。      

CHARACTERIZATION OF ARAB BERRI (EXTRA LIGHT) CRUDE FRACTIONŞ WITH EMPHASIS ON KINEMATIC VISCÓSITY-TEMPERATURE BEHAVIOR

The characterization data has been obtained for Arab Berri extra light crude oil (API° 46.9), which is one of the four crude oils being commercially produced by Saudi Arabia. Further, six true boiling point fractions (IBP-95°C, 95-205°C, 205-260°C, 260-34S°C, 345-455°C and 455°C+) of this crude were characterized in terms of API gravity, total sulfur, H₂S, merceptans, molecular weight, elemental analysis for total carbon, hydrogen and nitrogen, analysis of various metals and paraffin, aromatic and naphthalene contents of lighter fractions. The kinematic viscosity-temperature data have been obtained for 95°C+ TBP fractions for wide range of temperatures.     

STUDY ON PROCESSING SCHEME OF HIGH VISCOUS CRUDE FROM NO.1 SHUGUANG ZONE OF LIAOHE OIL

The characteristics of the high viscous crude from No.1 Shuguang Zone of Liaohe Oil Field are similar to those of residue distillates of general crude such as high density (ρ₂₀ = 0.9977 g.cm^-3), high viscidity (ν₁₀₀ = 1223.9 mm².s^-1) and high solidifying point(SP = 48°C). It contains no gasoline distillate and diesel yield is just 7.19%. And now it is only used as fuel. In order to make full use of this oil, the high viscous crude from No.1 Shuguang Zone of Liaohe Oil Field is evaluated comprehensively. And the properties of various distillates from the crude are analyzed and evaluated respectively. The results indicate that this oil contains less wax, but rich in resin and asphaltene, which belongs to low sulfur naphthene-base crude oil and can be used as feedstock to produce high paving asphalt. According to its characteristics, the optimum processing scheme is put forward and the high grade paving asphalts are produced by using the distillates higher than 350°C.     

准噶尔盆地南缘油气生成与分布规律——典型类型原油油源对比

准噶尔盆地南缘地区背斜众多,油气分布广泛,油气性质多样。该地区存在5套有效烃源岩,油-源关系十分复杂,长期以来对原油来源存在很大争议。系统采集了南缘地区5套烃源岩及不同构造原油样品,对烃源岩抽提物与原油碳同位素组成、正构烷烃及类异戊二烯烷烃分子碳同位素组成、生物标志物组成特征等进行了全面的对比分析。结果表明,南缘地区4种典型类型原油分别来源于不同时代的烃源岩:1第1类原油碳同位素组成轻,正构烷烃分子碳同位素分布比较平缓,含有较丰富的β-胡萝卜烷,甾烷以C₂₈、C₂₉规则甾烷为主,来源于二叠系烃源岩;2第2类原油碳同位素组成重,正构烷烃分子碳同位素分布比较平缓,Pr/Ph比值高,甾烷以C₂₉规则甾烷和重排甾烷为主,三环萜烷以C₁₉为主,伽马蜡烷含量很低,来源于侏罗纪煤系烃源岩;3第3类原油碳同位素组成轻,正构烷烃分子碳同位素分布随碳数增高大幅下降,Pr/Ph比值小于1.0,C₂₇、C₂₈、C₂₉甾烷呈"V"型分布,异胆甾烷、重排甾烷、Ts、C₂₉Ts、C₃₀重排藿烷、伽马蜡烷含量高,来源于白垩系清水河组烃源岩;4第4类原油碳同位素组成重,正构烷烃分子碳同位素分布随碳数增高下降幅度大,C₂₇、C₂₈、C₂₉甾烷呈"V"型分布且以ααα-20R为主,甲藻甾烷尤为丰富,来源于古近系安集海河组烃源岩。目前在南缘地区尚未发现三叠系烃源岩生成的原油。     

TWO STAGE DIRECT COAL GASIFICATION TO C2-C4 HYDROCARBONS

Results of a study conducted to convert coal to C₂-C₄ hydrocarbons in a two-stage reactor system are presented. Coal was converted to liquids at 440° C in a stirred batch autoclave using tetralin as the hydrogen donor solvent. The liquids produced were separated from the unreacted coal and ash by filtration. The liquids were then fed into a second stage fixed bed reactor containing sulfided Ni-M0/AI₂O₃ and Si0₂-AbO;5 catalyst. The liquids were hydrocracked on the dual-functional catalyst giving high yields of C₂-C₄ hydrocarbons. The pressure was 1800 psig and the temperatures were in the range of 425 to 500° C. Reaction mechanisms of conversion of coal derived liquids to C₂-C₄ hydrocarbons are presented. The kinetic parameters of the conversion of coal liquids to gases were determined. The activation energy was determined to be 23.9 Kcal/mol Cracking reactions involving C-C bonds appear to be rate-controlling.     

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。      

涠洲油田油气地球化学特征及成因类型探讨

中石化涠西探区2015年获重大突破,涠西南D洼东部斜坡发现了涠洲油田。为揭示原油的成因和来源,此文采用地质地球化学技术,通过GC、GC-MS分析表明,原油中链烷烃组分以低碳数正构烷烃为主,平滑分布;甾萜烷异构化程度较高,富含重排甾烷,具丰富的C₃₀4-甲基甾烷以及低碳数甾烷,C₂₇、C₂₈、C₂₉规则甾烷呈"V"型或"L"型分布。油-油、油-源对比表明,涠洲油田原油与流沙港组优质的深湖-半深湖相烃源岩具有成因联系。原油成熟度参数C₂₉甾烷αββ/（αββ+ααα）、C₃₁升藿烷22 S/（S+R）等表明原油已达成熟阶段,利用甲基菲指数MPI1折算原油成熟度分布在0.79~0.97之间,原油成熟度与涠西南D洼流沙港组烃源岩热演化程度相当。综合以上分析认为,涠洲油田的原油表现为典型湖相特征,主要来源于涠西南D洼流沙港组烃源岩。     

AN EXPERIMENTAL STUDY OF THE EFFECT OF PARAFFINIC SOLVENTS ON THE ONSET AND BULK PRECIPITATION OF ASPHALTENES

Asphaltene onset concentration and bulk deposition were measured for a typical live reservoir oil titrated with n-C₆H₁₄, n-C₅H₁₂, n-C₄H₁₀, C₃H₈, C₂H₆, CH₄ and CO₂ at 100° C (212 ° F) and 29.9 MPa (4340 psia). The concentration of titrant at asphaltene onset was observed to decrease approximately in a linear fashion with decreasing molecular weight of the paraffinic solvent; CH₄ did not induce any asphaltene precipitation. Bulk deposition experiments were performed using a solvent: oil volume ratio of 10:1; the results indicated that the weight percent of asphaltenes precipitated increased exponentially with decreasing molecular weight of the paraffinic solvents. More importantly, the asphaltene molecular weight showed a maximum for n-C₄H₁₀ precipitated asphaltenes. Possible explanations for this unusual result are presented.