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吐哈盆地煤成烃研究新进展 总被引：7，自引：0，他引：7
运用生物标记物及碳同位素等地化参数对吐鲁番 -哈密盆地的原油及其源岩进行了油源对比 |结果将该区原油分为三类 :第一类原油 |根据生标特征分析其具有显著的淡水环境、藻含量低、细菌影响大、C29甾烷含量高、C304α- 甲基甾烷低、C24 四环烷和C19三环烷含量高和碳同位素偏重 (δ13C为 - 25‰~ - 27‰ )的特点 |初步对比结果 |本区西山窑组的煤是该类原油的主要源岩;第二类原油 |富含藻类物质(C27甾烷与C304α-甲基甾烷含量较高 ) |该类原油可能来自侏罗系的富藻湖相泥岩;第三类原油 |全油碳同位素δ13C为 - 30‰~ - 32‰ |这类原油的生标反映出其源岩相的特征为缺氧、咸水、中等含藻的湖相沉积 (高含量的伽玛蜡烷和 β-胡萝卜烷|C35/C34藿烷比值大等 )。 相似文献
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Origin and occurrence of 25-norhopanes: a statistical study 总被引：1，自引：0，他引：1
The alkane fraction of more than 200 rocks, biodegraded oils and non-biodegraded oils, have been analysed by means of computerized GC-MS, in order to investigate the effect of natural biodegradation on the occurrence of “demethylated hopanes”, i.e. 17α-25-norhopanes. The results obtained indicate that 25-norhopanes are preexisting biomarkers the concentration of which is enhanced by selective biodegradation of more readily degradable homologs, i.e. regular hopanes, rather than by demethylation of hopanes in reservoirs. However, the use of 25-norhopane enrichment as a palaebiodegradation indicator in apparently non-biodegraded oils is still valuable providing the initial background content in the corresponding source rocks is known. Furthermore, 25-norhopanes appear to be diagnostic of specific environmental conditions (marine and lacustrine source rocks, dysoxic and not very hypersaline). Lastly, one other (novel) bacterially resistant rearranged hopanoic compound, namely a C29 neohopane, is applicable for both biodegradation and maturation evaluation. 相似文献
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The triterpenol geochemistry of the Santa Monica Basin from the Southern California Borderland, off the U.S.A., is described from the study of two sets of trap deployments, five box cores (≈30 cm) and a hydroplastic core (≈1 m). The biogenic sources and diagenetic stability of the triterpenols are discussed.The 17β(H), 21β(H)-hopanols (22R isomer) occur in the carbon number range from 30 to 32 and their abundance is nearly uniform in the shallow sediment sections. However, the three hopanols follow the order of abundance, C32 > C31 C30, in deeper sections. Their concentrations spans from trace levels to 156 μg/g organic carbon (<15 ng to 7 μg/g dry sediment). Tetrahymanol (gammaceran-3β-ol) has been identified in all the samples except in one set of trap particles collected at 100 m water depth, from trace level (<1 μg) to 215 μg/g organic carbon (<20 ng to 9 μg/g dry sediment). Diplopterol is also detected in trace amounts in some samples. The triterpenols in the trap material generally increase with the water column depth and decrease with the subbottom depth in the sediment cores.The extended hopanols are either degradation products of polyhydroxybacteriohopanes or are biosynthesized by bacteria. Tetrahymanol is probably the only suggested biological precursor of gammacerane (the reduced counterpart of tetrahymanol), which has been recognized in numerous crude oils and lithified sediments. Although it has been reported earlier from Green River Shale and from a residual Pleistocene lake sediment, tetrahymanol has so far been positively identified from recent marine sediments only in two recent studies. The decreasing content of tetrahymanol in sedimentary depth profiles in the Santa Monica Basin would favor an origin for this compound in the water column or at the sediment surface. The ubiquitous occurrence of this compound throughout the study area suggests that this triterpenol most probably originates from primitive organisms (protozoa, bacteria?), hitherto not identified or, more likely, not yet analyzed for their lipid composition. 相似文献
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在原生动物门梨形四膜虫的无水热解模拟实验产物中,可溶有机质含量丰富,氯仿抽提物含量高达17.5%,其中总烃相对含量可达8.99%;烷烃馏分主要以具有奇碳数正烷烃优势和植烷优势,CPI值达1.2,Pr/Pb比值仅0.42,含有γ-和β-胡萝卜烷以及异常丰富的伽马蜡-2-烯和伽马蜡烷等生物标志物为特征,从而表明梨形四膜虫生存于还原性的咸水环境,热解产物仍然处于未成熟阶段.热解模拟实验的结果不仅再次证实梨形四膜虫仍不失为伽马蜡烷的一种主要的生源母质,而且还验证了由四膜虫醇脱水,形成中间产物伽马蜡-2-烯,以及加氢产物伽马蜡烷的成岩作用演化过程.据此还对前人提出的两种伽马蜡烷成因机理作了对比性的讨论. 相似文献
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三塘湖盆地芦草沟组烃源岩及其古环境 总被引：9，自引：3，他引：6
三塘湖盆地中二叠统芦草沟组分布于马朗凹陷和条湖凹陷西南部边缘,主要由碳酸盐岩和暗色泥岩组成,是盆地主力生油岩。碳酸盐岩、伽马蜡烷指数(GI)、原油碳同位素组成表明芦草沟组沉积于咸水-半咸水古水体环境中,其主要沉积中心位于盆地西南边缘东侧,呈北西-南东方向延伸,与区域构造延伸方向基本一致。芦草沟组时期的原型盆地范围比现在大,尤其是原型盆地的西南边界应位于现在边界的更西南部,从其碳酸盐岩厚度和伽马蜡烷含量的变化来看,三塘湖盆地与相邻的吐哈盆地和准噶尔盆地呈相互独立分隔的状态。 相似文献
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The black shale samples collected from two Neogene formations in the Klias Peninsula area, West Sabah, have been assessed
and characterized in details by gas chromatography, gas chromatography-mass spectrometry and a variety of organic geochemical
parameters. The aims of this study are to describe the characteristics of organic matter of these sediments in terms of source/type
of the organic matter, assess its thermal maturity and paleoenvironment of deposition, based primarily on biomarker distributions.
The results of both formations do not reveal significant differences within the rock extracts. The gas chromatograms of the
saturated hydrocarbon fractions of the Setap Shale and the Belait formations displayed monomodal n-alkane distributions and
nearly identical regular sterane compositions with a predominance of C27 regular steranes. These are consistent with open marine depositional environments dominated by marine biological matter.
Another related feature of these rock extracts is the presence of a high relative abundance of gammacerane, indicating anoxic
marine hypersaline source depositional environment. The relatively high abundance of common land plant-derived biomarkers,
such as bicadinanes and oleananes, is a clear indication of a major terrigenous input to the source of the extractable organic
matter. The predominance of oleanane biomarkers in both formations is indicative of angiospermis input and Tertiary source
rocks. The high C29/C30 hopane ratios, moderate development of C33–C35 hopanes, high abundance of tricyclic terpanes and a slight predominance of C27 regular sterane over C28 and C29 steranes are characteristic features tending to suggest a significant marine influence on these source rocks, thereby suggesting
a mixed source input. The 22S/(22S+22R)C32 hopane ratio has reached equilibrium, and this is supported by the high maturity level as indicated by the 22S/22SC31–33 extended hopane ratios and 20S/(20S+20R)C29 regular steranes ratios. 相似文献
7.
Six oils and seven suspected source rocks from the Jianghan saline basin, in the central eastern part of China, have been examined using a variety of geochemical techniques. The results from this study show that oils from the third and fourth sections of the Qianjiang Formation (Eocene) are derived from similar source materials but have a different source from the oils of Xingouzui Formation (Eocene) in the same basin. The oils of the Xingouzui Formation (Eocene) are more mature, and probably have a greater input of terrigenous source material and in all probability have migrated greater distances than the Qianjiang oils. Oils from these sections are derived from an environment characterized as being extremely anoxic, strongly reducing and highly saline. The suspected source rocks examined in the study were from the Qianjiang Formation and were generally mature, except for the shallowest sample. The biomarker distributions in the suspected source rocks examined from the Qianjiang Formation were very different from those of the oils present in the same sections. It is proposed that oils from the Qianjiang Formation have sources in addition to, or exclusive of, the suspected source rocks examined in this study. 相似文献
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