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1.
The Jiyang Sag and the Liaohe Basin are the two important areas where immature oil resources are distributed in China. From
these two areas immature-low mature to mature oil samples were collected for carbon isotopic analysis. The extracts of source
rocks are dominant in the Jiyang Sag while crude oils are dominant in the Liaohe Basin. The maturity index, Ro, for source rocks varies from 0.25% (immature) to 0.65% (mature). Studies have shown that within this range of Ro values the extracts of source rocks and crude oils, as well as their fraction components, have experienced observable carbon
isotope fractionation. The carbon isotopic values tend to increase with burial depth, the oils become from immature-low mature
to mature, and the rules of evolution of oils show a three-stage evolution pattern, i. e., light→heavy→light→heavy oils. Such
variation trend seems to be related to the occurrence of two hydrocarbon-generating processes and the main hydrocarbon-forming
materials being correspondingly non-hydrocarbons and possessing MAB characteristics, lower thermodynamic effects and other
factors. In the process towards the mature stage, with increasing thermodynamic effects, the thermal degradation of kerogens
into oil has become the leading factor, and correspondingly the bond-breaking ratio of12C-13C also increases, making the relatively12C-rich materials at the low mature stage evolve again towards13C enrichment.
This research project was granted by both the 960006 Project of China Petroleum and Natural Gas Co. and the National Natural
Science Foundation of China (Grant No. 49973010). 相似文献
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东濮凹陷盐湖相油气成因与成藏机理研究薄弱。采用色谱/质谱(GC/MS)等常规技术,结合傅立叶变换离子回旋共振质谱、单体烃碳同位素技术,对东濮凹陷北部文明寨、卫城地区油气特征及其成因进行了解剖。结果表明,该区原油具有植烷对姥鲛烷优势显著、伽马蜡烷富集、升藿烷“翘尾”、甾烷异构化程度较低等咸水、盐湖相原油的典型特征。原油还具有正构烷烃单体烃碳同位素呈低碳重、高碳轻、近两段式分布的特征,与柴达木盐湖相原油有所差异。原油中检测到丰富的S1、S2、O1S1、N1、O1、O2、O3等芳构化程度较低的NSO化合物,其与该区低熟油的形成关系密切。油-油、油-岩详细对比表明,东濮凹陷北部原油主要来自埋深超过3 000 m的沙三—沙四段烃源岩、存在不同成熟度原油混合聚集现象。研究结果对该区进一步油气勘探具有重要指示意义。 相似文献
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Molecular fossils and sources of Cambrian heavy oil of Well Tadong-2 in the Tarim Basin,Xinjiang, China 总被引：1，自引：1，他引：0
Research on the molecular fossil characteristics of heavy oil from Well Tadong-2 is of great importance to constrain the source
of marine crude oils in the Tarim Basin, Xinjiang, China. The authors synthetically applied the isotope mass spectrograph,
chromatography and chromatography-mass spectrography to the studies of molecular fossil characteristics of heavy oil from
Well Tadong-2 in the Tarim Basin, and the results obtained revealed that heavy oil from Well Tadong-2 is characterized by
high gammacerane, high C28 sterane, low rearranged sterane and high C27-triaromatic steroid, these characteristics are similar to those of Cambrian-Lower Ordovician source rocks, demonstrating
that Cambrian crude oils came from Cambrian-Lower Ordovician source rocks; condensed compounds (fluoranthene, pyrene, benzo[a]anthracene,
bow, benzo fluoranthene, benzopyrene) of high abundance were detected in heavy oil from Well Tadong-2, and the carbon isotopic
values of whole oil are evidently heavy, all the above characteristics revealed that hydrocarbons in the crude oils became
densified in response to thermal alteration. 相似文献
7.
柴达木盆地第三系油源对比 总被引：16，自引：3，他引：16
本文利用生物标记化合物,着重讨论了柴达木盆地第三系内陆盐湖相地层中的油源对比问题.主要应用甾烷的母源参数与成熟度参数相结合的方法,和油/岩综合指纹类型曲线对比法.查明了这组同时代但不同成熟度的原油,各有其相应成熟级别(未成熟、低成熟、成熟和高成熟)的源岩.表明它们是不同成烃演化阶段的产物.研究证明,迄今柴达木盆地所找到的石油,大部分是低成熟的,而成熟和高成熟的油气资源还有很大的勘探前景. 相似文献
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对北黄海盆地LV井中、上侏罗统烃源岩及上侏罗统原油（油砂抽提物）进行常规有机地球化学分析和碳同位素测试,分析研究烃源岩和原油的地球化学特征并探讨原油的来源问题。测试结果显示,侏罗系烃源岩达成熟-高熟阶段,有机质类型以Ⅲ型为主。中侏罗统烃源岩有机碳含量较高,但生烃潜能、氯仿沥青“A”及总烃含量低值,属于差的烃源岩。干酪根碳同位素总体偏重（-24.4‰～-23.5‰）,与原油碳同位素特征（-29‰左右）差异显著,排除与原油的母岩关系。上侏罗统烃源岩有机碳含量较中侏罗统低,但生烃潜能、氯仿沥青“A”及总烃含量高值。上侏罗统烃源岩抽提氯仿沥青“A”碳同位素（-26‰～-21.5‰）特征、单体烃碳同位素分布模式及甾萜烷生物标志物特征都与原油相似,综合分析认为原油应该来源于上侏罗统中干酪根类型较好、母质为混源的成熟烃源岩。 相似文献
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藏北南羌塘盆地扎仁地区油苗地球化学特征及意义 总被引：3，自引：0，他引：3
扎仁地区地处南羌塘盆地南缘,属油气研究的“空白区”,结合羌塘盆地扎仁区块1∶〖KG-*2〗5万石油地质构造详查,重点研究了位于该区的地表油苗的生物标志化合物和分子碳同位素特征,并且进行了油源对比。研究资料揭示了原油有机质母质为菌藻类和高等植物,特别是藻类为原油的形成作出了贡献;原油形成于还原—弱还原的咸水环境,显示成熟原油的特征。原油的生物标志物特征和中侏罗统夏里组烃源岩具有亲缘关系,反映了原油主要来源于夏里组烃源岩,但其单体碳同位素特征又与夏里组烃源岩存在一定的差异,反映了混合来源的特征。 相似文献
10.
GAO Gang XU Xinde QU Tong GAN Jun DANG Wenlong ZHOU Xiaoxiao LIU Fengyan 《《地质学报》英文版》2020,94(5):1515-1530
Crude oil has been discovered in the Paleogene and Neogene units of the Weixinan Sag in the Beibu Gulf Basin. To determine the source and accumulation mode of this crude oil, 12 crude oil samples and 27 source rock samples were collected and an extensive organic geochemical analysis was conducted on them. Based on the geological conditions and the analytical results, the types, origins and accumulation patterns of crude oil in the study area were elucidated. Except for a shallowly-buried and biodegraded crude oil deposit in Neogene rocks, the crude oil samples in the study area were normal. All of the crude oils were derived from lacustrine source rocks. According to biomarker compositions, the crude oils could be divided into two families, A and B, distinctions that were reinforced by differences in carbon isotope composition and spatial distribution. Oil-source correlation analysis based on biomarkers revealed that Family A oils were derived from the mature oil shale at the bottom of the second member of the Liushagang Formation, while the Family B oils formed in the mature shale of the Liushagang Formation. The Family A oils, generated by oil shale, mainly migrated laterally along sand bodies and were then redistributed in adjacent reservoirs above and below the oil shale layer, as well as in shallow layers at high structural positions, occupying a wide distribution range. The Family B oils were generated by other shale units before migrating vertically along faults to form reservoirs nearby, resulting in a narrow distribution range. 相似文献
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Nineteen core samples of potential source rocks for crude oils in the Eastern Molasse Basin were investigated with respect to their isotopic composition of stable carbon in organic extracts and kerogens. p] Some of the chemical and isotopic results give positive or negative indications for the relationship between crude oils and the selected core samples. The analytical data point to the clayish sediments of the Rupelian and Sannoisian as probable source rocks, but further sampling and methodological research will be necessary to confirm the preliminary results on these samples which proved to be of low maturity by their elementary composition. 相似文献
12.
Maowen Li Yongqiang Xiong Lloyd R. Snowdon Dale Issler 《Journal of Geochemical Exploration》2006,89(1-3):214
Molecular and isotopic compositions of crude oils in the Beaufort–Mackenzie Basin confirm three genetic end-member oil groups and suggest extensive cross-formational hydrocarbon fluid flows in the Tertiary deltaic system. Inter- and intra-fractional variations in the geochemistry of the Tertiary-reservoired oils indicate that the oil source/maturity signatures were substantially masked by biomarkers that were picked up along migration pathways. Thus, many of the previously recognized “immature non-marine oils” are in fact thermally mature, probably derived from unpenetrated deeper marine source rocks. Although the effective source rock volumes have not been evaluated and their exact stratigraphic levels remain unknown, the relative timing of oil generation versus trap formation, rather than poor source quality, may be the cause of under-filled traps in the offshore area. 相似文献
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通过系统采集新疆三塘湖盆地马朗凹陷二叠系芦草沟组和条湖组各套烃源岩岩心样品以及条湖组凝灰岩段原油样品,研究各套烃源岩的基本地球化学特征、烃源岩和 原油饱和烃生物标志化合物特征、抽提物/原油以及族组分的稳定碳同位素特征等,探讨了凝灰岩油藏的原油来源。结果表明：芦草沟组二段烃源岩的质量最好;各套泥质烃源岩可溶有机质生物标志化合 物特征具有明显的差异,主要表现在Pr/Ph、 γ蜡烷含量、β-胡萝卜烷含量以及规则甾烷ααα20RC27、ααα20RC28、ααα20RC29相对含量等方面;条湖组凝灰岩油藏中原油具有低Pr/Ph、高γ蜡 烷含量、高β-胡萝卜烷含量以及规则甾烷ααα20RC27、ααα20RC28、ααα20RC29中ααα20RC29最高和ααα20RC27最低(谱图呈上升直线型)、原油及族组分稳定碳同位素较轻的特点;油源对比 显示凝灰岩油藏的原油主要来自芦草沟组二段烃源岩,但也有凝灰岩自身有机质的贡献。 相似文献
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Origin of the Neogene shallow gas accumulations in the Jiyang Superdepression, Bohai Bay Basin 总被引：1，自引：0，他引：1
Guangyou Zhu Shuichang Zhang Qiang Jin Jinxing Dai Linye Zhang Jian Li 《Organic Geochemistry》2005,36(12):1650
Natural gas resources occur extensively along the east coast of China, with a number of large and medium-sized gas fields being discovered in recent years. Gas reservoirs include Neogene, Paleogene and the underlying Mesozoic and Paleozoic basement. Of the total proven natural gas reserves in the Jiyang Superdepression, Bohai Bay Basin, almost 89.7% is present in the shallow Neogene gas pools, in traps formed on top of the paleotopographic highs and along the margin of the secondary depressions. These gases are closely associated with heavy oils, occurring as gas caps or associated gases within the heavy oil pools, or in separate gas pools above, or updip from, the heavy oil pools. The gases contain over 95% methane and small quantities of alkanes, nitrogen and carbon dioxide. The stable carbon isotopes of methane in these gases are up to 10‰ more positive than those of the thermogenic gases in the deep Paleogene reservoirs, with propane more enriched in 13C than butane. This study demonstrated that the majority of the petroleum source rocks in the Jiyang Superdepression tend to be oil-prone, and are currently within or shallower than the conventional oil window (0.45–1.0% Ro). The chemical and carbon isotopic compositions of the gases, together with the moderate to severe biodegradation of the associated heavy oils in the shallow Neogene strata, clearly suggest that the formation of the shallow natural gases in the Jiyang Superdepression result from the anaerobic degradation of accumulated oils in reservoir. 相似文献
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Delu Li Rongxi Li Baoping Wang Zhi Liu Xiaoli Wu Futian Liu Bangsheng Zhao Jinghua Cheng Wenbin Kang 《中国地球化学学报》2016,35(4):408-420
In the south of the Ordos Basin, the oil source of the Upper Triassic Yanchang Formation is confused all the time, which affects further exploration. In this study, oil sources from the oil layers of Ch6, Ch8 and Ch9 are all analyzed and confirmed. Through their carbon isotope value and biomarkers, characteristics of crude oils from the Yanchang Formation are analyzed. Then, the oil–source relation is discussed, with the source rocks’ features. Finally, the oil–source relation is calculated through cluster analysis. It is believed that the oils from the Yanchang Formation deposit in a similar redox environment, with weak oxidation–weak reduction, and have all entered maturity stage. Ch9 crude oil is more mature than crude oils from Ch6 and Ch8, and has more advanced plants and fewer algae. Gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS) analysis show that crude oils from Ch6 and Ch8 may come from Ch7, and Ch9 crude oil may not. Cluster analysis displays that crude oils from Ch6 and Ch8 have closer squared Euclidean distance with Ch7 source rocks than Ch9 crude oil does, indicating crude oils from Ch6 and Ch8 stem from Ch7 source rocks. And Ch9 crude oil has rather close squared Euclidean distance with Ch9 source rocks, illustrating Ch9 crude oil may be from Ch9 source rocks. This research may provide the theoretical basis for the next exploration deploy in the south of Ordos Basin. 相似文献
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首次报道了在惠州凹陷文昌组优质烃源岩及相关原油中普遍存在丰富的2-甲基藿烷系列生物标志物,而在恩平组烃源岩中则几乎缺乏这类生物标志物,其分布具有明显的专一性。这类特殊生物标志物在该地区沉积地层中分布特征的专一性是由不同时期沉积水体的水化学条件决定的。生物化学的研究结果表明,蓝细菌中富含2-甲基藿烷多醇,它们是2-甲基藿烷系列的前身物,因此蓝细菌是这类生物标志物的主要生物来源。依据现有的文献资料,发现较丰富的2-甲基藿烷系列大多出现在碳酸盐岩沉积中,显然这是一种偏碱性的水介质条件,可能暗示着这样的环境有利于蓝细菌的大量发育,这也可能是控制惠州凹陷文昌组和恩平组烃源岩中2-甲基藿烷系列分布规律的主要因素。2-甲基藿烷系列在不同层位烃源岩中分布的专一性可以作为确定原油的成因类型和追溯原油的来源可靠的指标。 相似文献
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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. 相似文献
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G.T Philippi 《Geochimica et cosmochimica acta》1977,41(1):33-52
Paraffinic crude oils are designated ‘primary’ because their composition is very close or identical to that of the hydrocarbons extracted from the corresponding oil source rocks. Heavy and medium-gravity naphthenic crude oils, on the other hand, typically are quite different compositionally from hydrocarbon mixtures in either mature or immature shales.The normal paraffin carbon number odd/even ratio 2C29/(C28 + C30) of all the heavy to medium-gravity crude oils which could be analysed are in exactly the same range as is observed for the primary paraffinic crude oils, namely 0.95–1.42. The naphthene indices of the medium to heavy gravity naphthenic crude oils and of the primary paraffinic crude oils from the same area are identical or close. These facts are significant because both the n-paraffin carbon number odd/even ratio and the naphthene index of shale hydrocarbons are strongly depth and subsurface temperature dependent. The facts observed demonstrate beyond question that, in the same area, the paraffinic precursors of the heavy to medium-gravity naphthenic crude oils are generated and expelled in the identical depth range, and from the same mature relatively deep oil source beds as the primary paraffinic crude oils. Later, during and/or after a generally upward migration into oil reservoirs, the primary crude may be transformed compositionally into a naphthenic crude oil.In none of the five widely scattered oil basins studied are medium to heavy naphthenic crude oils found at temperatures greater than a limiting subsurface temperature. The abruptness of the temperature cutoff of the change in oil compositions in all five oil basins, as well as the average value of the cutoff temperature of 66°C (150°F), leaves no doubt that the mechanism of this crude oil transformation process is microbial.Optical activity, which was observed in narrow saturate hydrocarbon fractions of the 80–325°C range of all microbially transformed crude oils, but not in the primary untransformed oils, is strong additional evidence for the microbial nature of the crude oil transformation process. The observed optical activity is explained by the microbial digestion at different rates of optical antipodes present in the primary paraffinic crude oils.To gain perspective the vast scale of the microbial oil transformation process in nature is pointed out. Billions of tons of heavy to medium-gravity naphthenic crude oils, originating from the microbial transformation of primary paraffinic oils, are present in oil fields and tar sands all over the world. 相似文献
20.
塔里木阿瓦提凹陷乌鲁桥油苗地化特征及来源 总被引：1，自引：0，他引：1
阿瓦提凹陷乌鲁桥油苗全油碳同位素较重(-29.4‰)。在甲基菲分布分数图版上落在高成熟油区;甲基菲比值为2.03,高于塔里木盆地现已发现的高成熟凝析油和成熟度较高的原油,表明该油苗的成熟度高。萜烷、甾烷分布具有C29Ts、重排藿烷含量低,伽玛蜡烷丰度较高,中等—高丰度C28甾烷,低重排甾烷等分布特征。这与凹陷及其周缘的石炭系—二叠系、三叠系及中—上奥陶统这三套烃源岩的明显不同,而与寒武系烃源岩相似。综合分析认为乌鲁桥油苗来源于寒武系烃源岩成熟晚期阶段生成的烃类。 相似文献