塔里木盆地原油轻烃地球化学特征

通过塔里木盆地５４０个原油要品中轻烃,尤其是Ｃ７烃类异构烷烃、环烷烃和正构烷烃的研究,认识到２－ＭＨ与３－ＭＨ化合物之间的相关性要高于２－ＭＨ与２－ＭＰ化合物之间的相关性,而ＭＣＰ与ＭＣＨ的化合物之间的相关性最差。原油Ｋ１值分布在０．７８－１．５４之间,其中８０％原油样品的Ｋ１值为０．９０－１．２０。原油中（２－ＭＨ＋２,３－ＤＭＰ）与（３－ＭＨ＋２,４－ＤＭＰ）占总径（Ｃ４－Ｃ７）的百分比的变化     

Geochemical characteristics of Ordovician crude oils in the northwest of the Tahe oil field,Tarim basin

Forty-six crude oil samples were selected from the Ordovician in the northwestern part of the Tahe oilfield for detailed molecular geochemical and isotopic analysis, including group compositions, carbonhydrogen isotopes and gas chroma-tograms of saturated hydrocarbons, as well as the characteristics of terpane, sterane and other biomarkers, indicating that crude oils are of the same origin from different districts in the Tahe oilfield and were derived from the same source kitchen (or oil source formation), i.e., mainly stemming from marine hydrocarbons. Detailed studies of oil physical properties of 25-honpane revealed that such oils have heavy or thick oil qualities due to biodegradation. Comprehensive assessment in terms of five maturity parameters shows that the oils from the Ordovician with Ro values varying from 0.80% to 1.59% are widely distributed in the northwest of the Tahe oilfield.     

鄂尔多斯盆地陇东地区延长组原油地球化学特征及成因类型划分

利用原油与岩样抽提物的族组成分离与定量分析、饱和烃色谱色质、芳烃色谱色质等分析测试资料,系统分析了陇东地区延长组原油的地球化学特征,并研究了原油的成因类型。研究表明,陇东地区延长组原油均为正常油,组分以饱和烃馏分为主;原油的母质来源为低等水生生物与陆源高等植物的双重贡献;形成环境为淡水微咸水的水体环境、弱氧化还原的沉积环境;原油为成熟油,属于烃源岩生烃高峰时期的产物。根据C30重排藿烷的相对含量,可将原油划分为3类,第Ⅰ类原油C30重排藿烷含量最低,第Ⅱ类原油C30重排藿烷含量中等,第Ⅲ类原油C30重排藿烷含量最高。其中第Ⅰ类原油最多,来自于长7油页岩,该类原油分布广泛,白豹、西峰、合水、华庆以及姬塬地区均以该类原油为主;第Ⅱ、Ⅲ类原油样品较少,与暗色泥岩关系密切,零星分布于镇北以北,西峰以东地区。     

Geochemical characteristics of crude oils from Well Zheng-1 in the Junggar Basin, Xinjiang, China

Well Zheng-1 is located in the combined area of the central uplift and the north Tianshan piedmont depression in the Junggar Basin. Two oil-bearing beds are recognized at 4788–4797 m of the Lower Cretaceous Tugulu Formation (K1tg) and 4808.5–4812.5 m of the Lower Jurassic Sangonghe Formation (J1s). The geochemical characteristics of family composition, carbon isotopic composition, saturated hydrocarbons, sterane and terpane biomarkers and carotane of two crude oils are described in this paper. The results show that the geochemical characteristics of the two crude oils are basically similar to each other, indicating they were all derived mainly from the high mature, brine, algae-rich lake facies sediments. Oil-source correlation revealed that crude oils of the two beds were derived mainly from the source rocks of Permian and mixed by the oil derived from the source rocks of Jurassic and Triassic. This is consistent with the geological background with several sets of source rocks in the area studied.     

Geochemical characteristics of aromatic hydrocarbons in crude oils from the Linnan Subsag,Shandong Province,China

Abundant aromatic fractions were detected in oils from the Linnan subsag, including aphthalenes, phenanthrenes, triaromatic steroids, biphenyl, fluorenes, dibenzothiophenes, dibenzofuranes, as well as some typical higher plant-sourced compounds, such as pyrene, benzopyrene, fluoranthene, chryaene, benzofluoranthrene, perylene and cadalene. Occurrences of biomarkers indicate that oils from the Linnan subsag are typical terrestrially genetic oils. Developed in the depositional environment is a strong reduction condition typical of brackish-saline lake. Thermal evolution has entered into the mature-high mature stage.     

内蒙古西部额济纳旗祥探8井华力西期风化壳 原油地球化学特征

根据对祥探8井华力西末期风化壳原油地球化学特征的分析,原油具有饱和烃含量高,芳烃、非烃、沥青质含量低和全油C同位素轻的特点,生物标志化合物藿烷系列具有C30藿烷含量高,伽马蜡烷含量相对较高等特点,指示生烃母质类型好,沉积环境为高含盐的还原环境,烃源岩演化程度较高。与祥探9井烃源岩生物标志化合物特征一致,指示与石炭系烃源岩具有良好的亲缘关系。     

非洲Melut盆地北部不同地区原油有机地球化学特征及意义

为了明确Melut盆地北部不同地区原油母质来源、沉积环境及亲缘关系,采用饱和烃色谱及色谱-质谱方法,开展了盆地北部不同地区原油地球化学特征分析及对比。研究表明,盆地北部各地区原油正构烷烃无明显奇偶优势,Ts/Tm值1.36～3.47、C₃₁升藿烷22S/(22S+22R)比值0.54～0.60、αααC₂₉20S/(20S+20R)与C₂₉αββ/(ααα+αββ)比值大于0.4,总体表现为成熟原油;伽马蜡烷指数普遍小于0.1,C₂₁三环萜烷具有明显优势,Pr/Ph值0.97～2.31,均值1.61,指示其烃源岩形成于弱还原-弱氧化的淡水湖相环境;生油母质为II～III型混合型。不同地区原油母质来源及成熟度有差异：Moleeta次凹东坡原油为单峰后峰态分布,高碳数正构烷烃含量占优势,C₂₄TeT/C₂₃TT平均值大于1,具有明显的陆源高等植物贡献,原油成熟度较低,发育重质—中质油;Jamous次凹深洼区原油为前峰优势的双峰态分布,C₂₄     

Reservoir geochemistry of the Tazhong oilfield in the Tarim Basin, China, Part Ⅰ. Geochemical characteristics and genetic classification of crude oils

According to the assemblage characteristics of saturated hydrocarbon biomarkers in crude oils and their geochemical implications, this study has proposed, for the first time, the criteria for the genetic classification of crude oils in the Tazhong area of the Tarim Basin, China. Crude oils from the area studied are classified as three genetic types: type-Ⅰ is characterized by the low contents of C29 norhopane, extremely abundant contents of gammacerane, low contents of rearranged sterane and relatively high contents of regular C28 sterane; the geochemical properties of type-Ⅱ crude oils are opposite to those of type-Ⅰ crude oils; the parameters for type-Ⅲ crude oils are intermediate between type-Ⅰ and type-Ⅱ. Results of oil correlation indicated that type-Ⅰ crude oils were derived from Cambrian-Lower Ordovician hydrocarbon source rocks, type-Ⅱ curde oils originated from Middle-Upper Ordovician hydrocarbon source rocks and type-Ⅲ crude oils are of mixed origin.     

内蒙古西部额济纳旗祥探8井华力西期风化壳原油地球化学特征

根据对祥探8井华力西末期风化壳原油地球化学特征的分析,原油具有饱和烃含量高,芳烃、非烃、沥青质含量低和全油C同位素轻的特点,生物标志化合物藿烷系列具有C30藿烷含量高,伽马蜡烷含量相对较高等特点,指示生烃母质类型好,沉积环境为高含盐的还原环境,烃源岩演化程度较高。与祥探9井烃源岩生物标志化合物特征一致,指示与石炭系烃源岩具有良好的亲缘关系。     

Reservoir geochemistry of the Tazhong oilfield in the Tarim Basin, China, Part I. Geochemical characteristics and genetic classification of crude oils

1 Introduction Since the 1990’s of the 20th century, oil & gas geochemists have shifted their research focus on hydrocarbon source rocks in the past to that on reservoir rocks and oil reservoirs at present; their research field has been expanded from oil & gas exploration to the assessment of oil reservoirs and production & management. Therefore, reservoir geochemistry as a branch disciplinary of organic geochemistry is now attracting great concern of many oil & gas explorers and oilfield en…     

Geochemical characteristics of aromatic hydrocarbons in saline lacustrine crude oils and their significance as exemplified by the south area of western Qaidam Basin

Based on quantitative GC-MS analysis of 40 crude oil samples collected from the south area of western Qaidam Basin,one of the largest saline lacustrine basins in China,the geochemical characteristics of aromatic hydrocarbons in oils were studied systematically in this paper.Among those constitutes,naphthalene(43% 59%),phenanthrene(12% 21%) and taromatic-sterane series(6% 28%) were the main ones of aromatic hydrocarbons.The ratio of aromatic hydrocarbon maturity parameter vs.saturated hydrocarbon maturity parameter C 29 20S/(20S+20R) shows that some aromatic hydrocarbon maturity parameters are not suitable for low-mature oils,including MPI,MNR,DNR,etc.Meanwhile,maturity parameters for dibenzothiophene and taromatic-sterane series are more appropriate for low maturity saline lacustrine crude oils.Based on the ratio of 4,6-DMDBT/1,4-DMDBT,the R c values are within the range of 0.59% 0.72%.However,the abundance of dibenzothiophene(DBT) is low,and the dibenzofuran(DBF) content is even lower,suggesting that the crude oils were formed in a saline lacustrine anaerobic environment.The high abundance of C 26 triaromatic steroid also indicates that the source material is brackish water-saline water with strong reducibility.     

鄂尔多斯盆地姬塬-西峰地区原油地球化学特征及油源分析

采用色谱-质谱(GC-MS)、裂解-色谱-质谱(Py-GC-MS)、色谱-同位素比值质谱(GC-IRMS)等方法,系统地分析了鄂尔多斯盆地南部姬塬与西峰地区原油的地球化学特征,重新确定了原油成熟度及对应源岩的形成环境.分析表明,单体碳同位素组成偏轻,介于-30‰～-33‰之间.原油饱和烃馏分中五环三萜烷含量较高;藿烷以C30藿烷占优势,C29藿烷次之;含较高的18α(H)-30-降新藿烷(C29Ts);C30重排藿烷和伽马蜡烷含量较低;规则甾烷含量高并以C29甾烷为主,含一定的孕甾烷、升孕甾烷和重排甾烷;芳烃馏分中富含萘、菲系列化合物;沥青质裂解产物中芳基类异戊二烯烃含量很低.原油成熟度相当于镜质组反射率0.82%左右,是烃源岩在生油高峰阶段的产物.油源分析表明,该区原油主要来源于三叠系长7段泥岩,有机质形成于水体较深、淡水湖相沉积环境.     

Geochemical characteristics and genetic types of crude oils from the Tertiary system in the southern part of western Qaidam Basin, Northwest China

Crude oil samples taken from the southern part of western Qaidam Basin were analyzed with GC/MS in order to understand the geochemical characteristics of crude oils. The results reveal that most crude oils are characterized by high abundance of gammacerane and C35 homohopane, which are the representative characteristics of saline lacustrine crude oils. Based on the variation of the ratios of gammacerane/C30 hopane （G/H） and C35 homoho-pane/C34 homohopane （C35/C34H）, two crude oil groups, A and B, are identified. Group-A crude oils mainly occurr in the north of the study area, with higher ratios of G/H （〉0.8） and C35/C34H （〉1.2）, whereas group-B crude oils, selected from the south of the study area, show lower ratios of G/H （〈0.8） and C35/C34H （〈1.0）. In addition, group-A crude oils are distinguished into three subgroups in accordance with their different ratios of G/H and C35/C34H and different distribution characteristics of n-alkanes, isoprenoids and steranes. These may be helpful for understanding the distribution characteristics of crude oils in the southern part of western Qaidam Basin and providing clues to the forthcoming exploration of crude oils and gas.     

中国西北侏罗纪煤系显微组分热解油生物标志物特征及其意义

从西北地区侏罗纪煤中分离出来的不同显微组分热解油生物标志物总体上比较相似,但在一些特殊生物标志物的分布上存在明显差异。藻类体、孢子体、角质体热解油Pr/Ph比值一般在1.5～2.0之间,镜质体和基质镜质体热解油Pr/Ph比值在3～4之间,但均只有相应原煤抽提物Pr/Ph比值的一半。在常规生物标志物甾烷和萜烷组成中,藻类体和孢子体含有相对丰富的C27甾烷,角质体其次,镜质体和基质镜质体C27甾烷含量很低或者基本不含C27甾烷;藻类体和角质体含有较高的伽马蜡烷,而与藻类体来自相同原煤的孢子体伽马蜡烷含量很低;镜质体和基质镜质体基本上不含伽马蜡烷;分离显微组分的原煤伽马蜡烷含量均很低。由此可见,伽马蜡烷的含量不仅与有机质沉积水体的盐度有关,与母源的成分也有关系。显微组分热解油与煤系原油生物标志物组成特征对比表明,煤系原油是藻类体、孢子体、角质体等富氢组分和相对贫氢的镜质组生成产物的混合物。不同油气藏中的原油,每一类显微组分的贡献可能不尽相同,有些原油可能主要来源于藻类体和孢子体等富氢显微组分,而有些原油除了富氢显微组分有贡献外,镜质组对其也有一定的贡献,但富氢显微组分应该是煤系含油气盆地中主要的生油显微组分。     

乌兰花凹陷原油特征及成因

乌兰花凹陷是二连盆地南部新发现的富油凹陷,对乌兰花凹陷原油物理性质和地球化学性质进行了系统的分析以揭示其特征及来源。原油物理性质显示,乌兰花凹陷原油比重（API gravity）介于20.2°~40.0°之间,主体为正常原油。原油生物标志化合物参数表明,不同构造带之间原油特征存在差异,可以划分为两类原油。一类以土牧尔构造带原油为主,具有低姥值比（Pr/Ph）和C₂₁/C₂₃三环萜烷,相对较高的伽马蜡烷/C₃₁藿烷和规则甾烷/C₃₀藿烷的特征,原油主要为烃源岩在成熟阶段早期的产物,主要以藻类来源为主。另一类原油包括赛乌苏和红井构造带原油,具有高姥值比（Pr/Ph）和C₂₁/C₂₃三环萜烷,相对较低的伽马蜡烷/C₃₁藿烷和规则甾烷/C₃₀藿烷,主要为陆源有机质和藻类有机质混合来源,原油具有更高的成熟度。原油碳同位素和正构烷烃单体烃碳同位素表明这两类原油应是一套烃源岩在不同成熟阶段的产物,原油主要来源于南洼槽阿尔善组烃源岩。阿尔善组烃源岩的非均质性和成熟度导致了两类原油的差异。      

赤峰盆地元宝山凹陷稠油地球化学特征及成因

根据分子有机地球化学理论，借助色谱和色质等先进测试手段，对赤峰盆地元宝山凹陷6个油样进行了分析研究，结果表明，元宝山凹陷的原油属重质稠油，成熟度低，生源物质以菌类和藻类微生物为主，后者大于前者；其生源物质形成于半咸水－咸水湖相还原环境，利用有机显微组分荧光光谱研究了本区烃源岩的成烃机制，认为原油是生物类脂物早期生烃的产物，还对原油的稠化机理进行了分析，认为可能是由其生源物质决定的，而后期又受轻微生物降解的影响，这与前人的研究成果迥然不同，同时，将本区原油与其他熟知的典型稠油进行对比，突出了本区原油的特殊性。     

刍云深水凹陷高成熟原油芳烃地球化学特征研究

对白云凹陷采集的27个原油样品的芳烃组成进行了系统的研究。其分布特征和相对含量表明,原油母质具明显的陆源高等植物输入特征,沉积环境以氧化环境为主,根据萘系列、菲系列、二苯并噻吩系列化合物的相对含量分布差异,优选有效的烷基萘、烷基菲、烷基二苯并噻吩成熟度指标,综合分析了白云凹陷原油成熟度特征。原油总体属于成熟一高成熟原油,结合生物标志化合物组成可划分为A、B两类,A类原油的成熟度高于B类原油。还选用有效的成熟度参数探讨了白云凹陷油气运移规律,如三甲基萘比值,该参数指示油气运移方向沿白云主洼中心向周围运移,且邻近番禺低隆起,运移方向由西向东,即沿着成熟度由高到低方向运移。     

柴达木盆地北缘冷湖地区原油对比

借助色谱质谱测试,对柴达木盆地北缘冷湖地区冷湖三、四、五号构造上22 个原油样品的生物标志化合物组成进行了系统分析。根据萜烷和甾烷相对含量的不同,将该区原油分成为3 类,即低熟单源型原油、成熟混源型原油和高熟混源型原油。对比研究表明,冷湖三号、四号构造原油链烷烃表现为nC20 前低分子量优势,五号构造原油则表现为nC21 后高分子量优势,从三号至五号,原油中四环萜烷相对含量逐渐变小,而重排藿烷、重排甾烷相对含量依次增加,说明母源类型依次变差,而成熟度则依次变高。     

Compositional characteristics and geochemical significance of light hydrocarbons for crude oils in Tarim Basin, China

Light hydrocarbons, especially C7 isoalkanes, cyclopentanes, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically. The results suggested the K1 values [ （2-MH＋ 2,3-DMP）/（3-MH ＋ 2,4-DMP） ] of crude oils vary from a lowest value of 0.78, to a highest value of 1.54, but the K1 values of the majority of oil samples （80%） range from 0.90 to 1.20. However, the absolute contents of （ 2-methylhexane ＋ 2,3-dimethylpentane） and （ 3-methylhexane ＋ 2,4-dimethylpentane） in the total light hydrocarbons （ C4-C7 ） show a similar variation trend. The variation of K1 values of crude oils can suggest a typical sedimentary environment for source rocks. Therefore, according to the compositional characteristics of C7 light hydrocarbons in light of the steady-state catalytic hypothesis, nonmarine oils from the Yingmaili area and marine oils from the Tazhong uplift in the Tarim Basin were genetically classified.     

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-Ln1 1) showed remarkable migration fractionation in the vertical direction. From Ordovician reservoirs (O) to oil legs TⅢ and T Ⅰ of Triassic reservoirs in blocks LN1-LN11, the concentrations of [a] [c] decreased from 1. 59μg/g, 0.49μg/g to 0.17 μg/g (oil). The ratios of various alkylcarbazole isomers, such as 1,8-dimethylcarbazole/nitrogenpartially 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 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 TⅢ to TⅠ of Triassic reservoirs.