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1.
封闭体系有机质与有机碳氢氮恢复动力学研究 总被引:3,自引:0,他引:3
在封闭体系的条件下,对典型的Ⅰ、Ⅱ、Ⅲ型干酪根在热演化过程中的损失进行生烃动力学研究,获得了Ⅰ、Ⅱ、Ⅲ型干酪根的总量、有机碳、氢以及氮质量损失动力学参数。用Kinetics软件计算了封闭体系干酪根有机碳丰度、氢碳原子比和氮碳原子比的恢复系数。认为在对高成熟—过成熟干酪根进行生烃评价时,Ⅰ、Ⅲ型干酪根残余有机碳丰度需要进行恢复,而Ⅱ型干酪根残余有机碳丰度不需要恢复。三种类型干酪根的氢碳原子比均需要进行恢复。 相似文献
2.
Stratigraphy, sedimentology and bulk organic geochemistry of black shales from the Proterozoic Vindhyan Supergroup (central India) 总被引:1,自引:0,他引:1
Four organic-rich shale units of the Proterozoic Vindhyan sedimentary succession have been scanned to reveal their origin
and hydrocarbon potential. The wavy-crinkly nature of the carbonaceous laminae is suggestive of a microbial mat origin of
the shales. These shales are thus different from Phanerozoic black shales which typically exhibit planar laminae. The hydrocarbon
potential of the black shale units has been evaluated by Rock-Eval pyrolysis. Total organic carbon content of many of the
shales exceeds 1%. The meanT
max for the black shales translate to a vitrinite reflectance range of 2.05-2.40% Rm based on standard conversion techniques.
These shales have reached the catagenetic stage near the beginning of anthracite formation. 相似文献
3.
4.
Organism relics or kerogens in oils are first obsenred by a confocal laser scanning microscope (CLSM) and a transmission electron
microscope (TEM). The complexes of kerogens in oils are characterized by the presence of a great variety of microfossils or
macerals. These kerogens in oils are mainly the residues of the original organic substances from which oil formed, and minor
kerogens from enclosing rocks enter the oils, therefore, the components and types of the kerogens in crude oils can serve
as an indirect indicator of oil-source rock correlation. This method was applied to Jurassic oils in the Junggar Basin and
the Turpan-Hami Basin, and there are two types of the kerogens in oils: one containing a lot of macerals from terrestrial
plants may derive from coals, and the other, characterized by a high content of microscopic algae, fungus spores and Acritarch,
may originate from Permian organic matter. In addition, the reflectance of the vitrodetrinites in oils can be used as an indicator
of oil-source rock correlation. 相似文献
5.
孙玉壮 《中国地球化学学报》2004,23(2):101-111
Thirty-seven Kupferschiefer samples from southwestern Poland were analyzed by microscopy, Rock-Eval approach and instrumental neutron activation analysis to understand the geochemical and morphological characteristics of kerogen present in the samples. The analytical results indicate that there are two different types of kerogens. One type was only subjected to thermal alteration processes, and the other was further oxidized after deposition of the sediment.In the oxidized samples migrabitumen was transformed into pyrobitumen. Rock-Eval analyses show a significant decrease in HI values in the oxidized samples and an increase in OI values in relation to the samples that were not influenced by oxidation. Variations in S2 versus Corg contents indicate a change in kerogen from Type II to Type III with progressing oxidation. The presence of pyrobitumen and the depletion of hydrogen in the altered kerogen allow one to conclude that the kerogen was used as hydrogen donor for thermochemical sulfate reduction(TSR). 相似文献
6.
Qin Kuangzong 《Organic Geochemistry》1988,13(4-6)
Two Chinese immature oil shales from the continental deposits of kerogen type I and II have been thermally treated combined with the technique of supercritical fluid extraction at 630–650 K and 15–25 MPa in a semi-continuous laboratory scale apparatus. Toluence is selected as the solvent. Up to 70–80% of the kerogen matrix can be converted to a thermal bitumen and extracted simultaneously. The chemical structural parameters from the NMR, IR, XRD, ESR and EA analyses of the kerogen and the thermal bitumen show striking resemblance in nature. It implies that the thermal bitumen is primarily a depolymerized product of the kerogen. Based on the GC/MS spectra of the aliphatic eluate of the thermal bitumen, the predominance of the odd/even ratio of the alkanes and the epimeric ratios, such as 20S(20S + 20R) of C-29 steranes and 22S/(22S + 22R) of C-32 terpanes, show that the maturity of the thermal bitumen from these oil shales is comparable to that of commercial immature oils from East China. The thermal bitumen is thought to be an intermediate product of the thermal degradation of kerogen.Since the thermal bitumen is mainly composed of asphaltenes and resins, it has a structure of gel. The gel-state bitumen may turn to sol-state readily due to its low aromaticity and polarity, or due to selective adsorption of asphaltenes by clay minerals. Then the migration potential of the bitumen is enhanced.Consequently, under favorable geological conditions, the thermal depolymerization of kerogen seems to be a probable mechanism to explain the formation of immature oils. 相似文献
7.
Quantitative pyrolysis-gas chromatography has been performed on 96 kerogen samples isolated from 17 wells on the Norwegian Continental shelf. Petrographic and bulk geochemical measurements were also performed on the samples, and a combined data set of 117 variables for each sample was analysed using principal components analysis (PCA). This approach provides an objective and reproducible means of kerogen characterisation, which can be easily automated. In addition to objective kerogen characterisation and facile visualisation of facies and maturity related chemical trends, the method has the potential to allow objective prediction of key geochemical parameters such as maturity level from pyrogram data. 相似文献
8.
This study defines a chemical representation of the kerogen macromolecule based on data from physicochemical analyses. The model should permit: creation of various schematic drawings representing an average macromolecule; future integration of new analytical results (for instance on structures of biomarkers or biopolymers); and determination of the distribution of chemical bonds.The models developed in this study can be represented in a 3D space, using classical chemical symbols, in the form of cyclic groups linked to each other by aliphatic chains. One cyclic group is a connected set of aromatic, naphthenoaromatic or naphthenic rings. These cyclic groups are constructed using basic elements such as atoms and bonds defined by their length and direction.Modeling of kerogen is done in three successive steps. A library is first created to define atoms, bonds and cyclic groups. Secondly, starting from a set of equations describing the analytical results, cyclic and aliphatic groups are chosen in the appropriate stoechiometric amount to match the analytical data. Finally the construction is done: cyclic groups are placed randomly in a 3D space, connections are made by aliphatic chains, and functional groups are added.The molecular modeling software XmolTM can be operated on APOLLO stations. It allows the creation of libraries, the calculation of chemical bonds corresponding to the analyses and the construction of macromolecules. An example is given for a type III kerogen at the beginning of diagenesis. 相似文献
9.
Petroleum hydrocarbons are formed by breakdown of kerogen preserved in source rocks throughout the process of catagenesis. This process is accompanied by free radical generation in kerogen. The availability of measuring free radicals in kerogen using ESR to deduce a maturation estimation of potential source rocks has been hindered due to the presence of the solvent-extractable organic molecules (SEOM) trapped within the kerogen matrix. Spin concentration (Ns) of the kerogen treated with pyridine (KPy) represents the paramagnetic centers of the kerogen matrix itself and provides a potential parameter to evaluate kerogen maturation. 相似文献
10.
C.J. Clayton 《Organic Geochemistry》1991,17(6)
For modelling isotopic variations in oils it is convenient to differentiate the effects of oil generation ( 100–150°C) from the effects of oil to gas cracking ( 150–180°C). During generation, δ13C of kerogen may increase by up to 1% due to release of isotopically light oil and gas, although most kerogens show little or no chan δ13C of the generated oil increases by between 0 and 1% (av. 0.5%) due to mixing of isotopically heavy oil with an initial isotopically light unbound fraction, possibly of bacterial origin. The change occurs mostly over the first 20% of generation. During oil to gas cracking, kinetic isotope effects become important and the effect on δ13C of the remaining oil can be modelled as a Rayleigh process. δ13C increases by 1.5% by 50% cracking. Insufficient data are available to calibrate the effects at higher levels of cracking, and modelling these variations is hindered by a lack of understanding of the mechanism of pyrobitumen formation. However, increases greater than about 4% are unlikely to be observed. With increasing maturity, the low molecular weight fractions become isotopically heavy faster than the high molecular weight fractions. As a result, any separation of the low molecular weight fraction into a gas phase (“condensate formation”) will produce an isotopic difference between oil and condensate that depends on maturity. In the early stages of generation the condensate may be up to 1% lighter than the remaining oil. With increasing maturity, this difference at first decreases and then increases in the opposite sense. By half way through oil to gas cracking the condensate may be 1.5% heavier than the residual liquid. More subtle rearrangement reactions may result in small, but significant, changes to the shape of the isotope “type-curves” when different oil fractions are compared. 相似文献