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1.
运用镜质组反射率、袍子体荧光参数、生物标志物参数详细研究了三塘湖盆地中生界烃源岩的有机质热演化特征及演化阶段。研究表明镜质组反射率是该区有机质热汪化最可靠听成熟度参数,孢子体荧光参数是重要的热演化指标,生物标志物参数是有效的热演化指标。三塘湖盆地有机质总体热演化水平较低,且在横向和纵向上存在明显的差异。该区的有机质热演化具有明显的阶段性,运用成熟度参数将其划分为未成熟和成熟两个阶段。  相似文献   

2.
上奥陶统五峰组-下志留统龙马溪组海相页岩是四川盆地下古生界主要的烃源岩和页岩气勘探目标,有机质成熟度不仅是油气生成评价的关键,也是页岩品质评价的重要指标之一.下古生界页岩有机质成熟度一直以来是有机岩石学研究的难点与热点问题.由于下古生界缺乏镜质体,先前的研究多是采用沥青反射率转换为等效镜质体反射率的方法,并且由于沥青的局限性和不确定性,使得五峰-龙马溪组页岩的成熟度缺乏统一的认识和系统研究.通过采集四川盆地及其周缘的岩心和露头样品,系统分析了页岩有机显微组分光学反射率特征.结果表明笔石和固体沥青是最主要的两类有机显微组分.根据固体沥青的显微结构形态和光性特征,将固体沥青大体上分为两类:(1)颗粒状-棱角状的充填在孔隙和微裂缝中高反射率焦沥青;(2)以细小不规则表面的有机质颗粒大量分散于粘土矿物基质中的低反射率基质固体沥青.焦沥青与笔石随机反射率均可以表征下古生界页岩有机质成熟度.但焦沥青反射率略低于笔石反射率,并且随着成熟度的增高,笔石反射率的增速大于焦沥青,各向异性也显著增强.相对于固体沥青反射率,笔石随机反射率分布更为集中,更适合作为含笔石页岩有机质成熟度指标.但是笔石反射率与等效镜质体反射率在过成熟阶段的换算关系需要进一步研究.   相似文献   

3.
张丽洁  李光宣 《地球化学》1996,25(4):339-345
本文对云南楚雄中生代盆地上三叠统煤成烃源层进行了原始有机质丰度和原始产烃潜力恢复的尝试。该烃源层在盆地中具有不均衡热变的特点,南北之间的R0可由0.8%变化到4.5%不等,东西向的差异也很明显。在各区因排烃量不同而造成有机质残余率不等的情况下,如何恢复其原始有机质丰度和原始产烃潜力,以便进行合理的油气资源评价成为该盆地勘探工作的重要课题。作者通过对生源相近、成煤环境类似而成熟度极低的本区晚第三纪煤系和上三叠统变质最低的华坪煤系样品,按不同温阶进行系统的外加温、外加压生烃排烃模拟实验,从而分别编制出热演化程度与其排烃率(R0-HC排)和有机碳损耗率(R0-C损)的关系曲线。利用楚雄盆地上三叠统煤成烃源层相同比例尺的残余有机碳平均含量等值线图和平均R0等值线图叠合,获得两种曲线的若干交汇点。基于各交汇点的R0值和经过换算的有机碳损耗率,分别从R0-C报和R0-HC排曲线上求出各交汇点已损失的有机碳百分率和已排出烃类的百分率,从而恢复了各点所在烃源层的原始有机碳丰度和原始产烃潜力。  相似文献   

4.
陈善庆 《地球学报》1995,16(2):211-226
本文主要研究扬子地台西部黄陵背斜周缘早古生代有机壳化石的特征、光学特性和有机质成熟度规律,同时较为详细地研究了有机壳化石反射率随热成熟度变化特点与镜质组反射率之间的关系。提出该区以有机壳化石反射率为主要指标的有机质成熟度划分方案。认为笔石、几丁虫和虫牙等有机壳化石在形态、结构和构造上具有各自的特征,并具有突起、反射色、显微结构构造、非均性、异向光性、反射率和双反射现象等光学特征。有机壳化石反射率与  相似文献   

5.
早古生代海相烃源岩成熟度的有机岩石学评价方法   总被引:12,自引:1,他引:11  
肖贤明  吴治君 《沉积学报》1995,13(2):112-119
本文应用有机岩石化学方法通过对塔里木盆地早古生代典型烃源岩研究,建立起了应用沥青反射率、微粒体反射率、动物壳属体反射率及海相镜质体反射率评价烃岩成熟度的综合标准。  相似文献   

6.
恢复地层剥蚀厚度的最优化方法   总被引:19,自引:0,他引:19  
传统的恢复地层剥蚀厚度的方法是利用钻井、声波和地震资料。但限于各种地质条件而不能广泛应用。本文采取最优化方法,在计算成熟度的数学模型基础上,根据剖面上实测R。值实现对热史的反演求得剥蚀厚度。  相似文献   

7.
Thirty-one rock samples from a Western Canada Basin well have been analysed for aromatics, using glass capillary gas chromatography with simultaneous flame ionization and sulfur-selective flame photometric detection. A uniform aromatic distribution pattern with a marked predominance of di- and tricyclic aromatic hydrocarbons was observed throughout a depth interval of 3000 meters comprising Cretaceous and Jurassic sediments. The very high relative abundance of sulfur aromatics at two narrow intervals in the Triassic and Mississippian is attributed to a major change in facies. Gradual changes with increasing depth have been observed for a series of compound ratios, which had been calculated from the isomers of methyl- and dimethylphenanthrene, and their parent compounds. These changes reflect the increasing thermal maturation of the sedimentary organic matter. A Methylphenanthrene Index (MPI) has been introduced, which exhibited a very good correlation with vitrinite reflectance data. The MPI is the first maturity parameter which is based on a series of aromatic hydrocarbons. This hydrocarbon internal maturity parameter permits the recognition and definition of maturity levels in extracts which can be compared to the maturity (e.g. vitrinite reflectance) of source rocks.  相似文献   

8.
在对比分析不同侵入体热传导模型的基础上,进一步结合Easy Ro%模型对前人报道的受岩浆侵入体影响的实测Ro数据进行了数值模拟,结果表明改进的Fjeldskaar模型具有较好的应用前景。同时侵入体不同初始温度及不同厚度对围岩热演化程度影响的数值模拟结果表明,岩浆侵入体的热作用范围有限,不同地质条件下,影响的范围不同。其中:侵入体初始温度越高,影响范围越大;侵入体厚度越大,影响范围(X/D值)也越大,但是一般X/D<2(X/D代表侵入体与接触面的距离和侵入体厚度的比值)。侵入体热传导模型的初步应用表明,岩浆作用带来的热源对烃源岩生烃进程产生了重要影响,可以加速烃源岩的成熟,使得生烃期提前。  相似文献   

9.
The organic matter content of the Paleocene Aaliji Formation has been studied from the Qm-1 well in the Qumar Oil Field, NE Iraq. A palynofacies analysis revealed the obvious domination of amorphous organic matter (AOM) in the samples studied in addition to the different ratios of palynomorphs, phytoclasts and opaque organic material. The deposition of the various percentages of organic matter components and types of palynomorphs appear to have occurred in a proximal suboxic–anoxic basinal environment. The samples analysed showed relatively low percentages of total organic carbon, indicating a generally poor source rock. The thermal alteration index for the palynomorphs (dinoflagellates) observed and identified ranged between 2, 2+ and 3?, indicating an immature to early stage of maturity for the section studied. No clear differentiation between the stages of maturity within the section was identified. The reflectance measured for a few vitrinite particles at a depth of 2,900 m showed uncertainly of 0.46 % Ro, indicating a still thermally immature stage. The values obtained from pyrolysis analysis also supported the formation being in the early stages of maturity, i.e. an immature condition, with T max values between 416 and 435 °C. The quality of the organic matter examined and analysed appeared to be mostly type III gas-prone kerogen, as discerned from the hydrogen index, oxygen index and other pyrolysis parameters. The parameters obtained and calculated from gas chromatography analysis performed on a sample at a depth of 2,900 m found marginally mature marine source organic matter.  相似文献   

10.
The aim of this study was first to review or even identify reliable diagnostic criteria to distinguish recycled and autochthonous vitrinite particles and, second, to examine and try to explain the impact of weathering and reburial on optical changes (reflectance) of recycled material. The work was based on indigenous and recycled particles of two sample sets from two wells drilled in the Senegalese margin basin and the Ardèche paleomargin (SE France), respectively. In addition to reflectance measurements, the studied samples have also been analysed by Rock-Eval pyrolysis. For both sample sets, hydrogen index (HI) and oxygen index (OI) values suggest a type III organic matter of dominant terrestrial origin.Two main diagnostic criteria appear particularly useful to identify indigenous and recycled vitrinite particles: the first is the clear genetic relationship between telinite and collotelinite; the second is the presence of pyrite framboid inclusions in indigenous vitrinite. The pyrite–vitrinite association illustrates the relationship between sulphate reduction, pyritisation, and in situ organic matter transformation through gelification process. However, application of both diagnostic criteria requires some additional information about depositional conditions (i.e., anoxicity) and thermal maturity of the studied samples. Weathering has no or only very limited effect on vitrinite reflectance. During their new burial history, recycled vitrinites follow a reflectance evolution path close to that of inertinites and thus appear as transitional materials between vitrinite and inertinite macerals. Consistently, this behaviour implies that recycled vitrinite reflectance changes during burial diagenesis do not solely depend on their chemical composition but, most probably too, on combined chemical and structural changes inherited from their past burial history and from the impact of weathering during their recycling stage.  相似文献   

11.
动物碎屑的光性变化及其研究意义   总被引:1,自引:0,他引:1  
前泥盆纪地层中缺乏镜质体使得正确评价其有机质的热成熟度极为困难。但在下古生界中含有海生有机质笔石和几丁虫等 ,由于其光性特征随成熟度的变化而发生规律性变化而被用于表征有机质成熟度。在 4 50~ 70 0nm可见光谱范围 ,由于笔石和几丁虫的光学色散特性反射率随成熟度增加 ,表现出与镜质体及沥青相似的变化趋势。这表明 ,随成熟度增加 ,笔石和几丁虫的分子结构芳香度及芳碳定向性均发生相似的变化。在低成熟阶段 ,笔石和几丁虫的光学色散谱从蓝区到红区降低 ,表明芳环聚合程度低 ,芳碳含量少。在中等成熟阶段 ,笔石和几丁虫的光学色散谱从蓝区到红区呈平稳型式。在高成熟阶段 ,笔石的光学色散谱从蓝区到红区呈上升趋势 ,表明具有高芳香度 ,芳香分子定向性增强。在Ro ,max为 2 5%左右笔石发生结构转化 ,但直到Ro ,max达 12 %也未发生石墨化作用 ,表明笔石主要发生增碳作用。笔石和几丁虫的光性参数是下古生界地层的极为有效的成熟度指标  相似文献   

12.
Since the mid-1980s, Texaco has used the transmittance color index (TCI) of amorphous kerogen as an indicator of kerogen thermal maturation. The technique simply involves the direct measurement of a white-light spectrum as it is transmitted through a particle of amorphous organic matter (AOM). In brief, TCI values are obtained by the analysis of white light originating from a 100-W 6-V tungsten lamp attached to a photometric microscope. The assignment of particular TCI values is based on the increasing curvature of spectra with increasing maturity. TCI curves shift from an average wavelength around 580 nm for samples of immature, amorphous kerogen (i.e., material with a mean, random vitrinite reflectance of about 0.20%) to about 660 nm for samples containing very dark brown to some black particulate material (i.e., kerogen with a mean, random vitrinite reflectance of about 2.15%). The range of TCI values covers all zones of petroleum generation and preservation. In our opinion, TCI can provide as accurate a basis for maturation interpretations as is available from vitrinite reflectance (or from the mean random reflectance of some zooclasts, such as graptolites and chitinozoans), or the widely used visual estimate the thermal alteration index (TAI) or the similarly determined conodont color index (CAI). TCI is probably most useful, however, in those situations where the rocks to be examined have not yet reached the semianthricite coalification stage (≈2.0% vitrinite reflectance).  相似文献   

13.
The development of a qualifying system for reflectance analysis has been the scope of a working group within the International Committee for Coal and Organic Petrology (ICCP) since 1999, when J. Koch presented a system to qualify vitrinite particles according to their size, proximity to bright components and homogeneity of the surface. After some years of work aimed at improving the classification system using photomicrographs, it was decided to run a round robin exercise on microscopy samples. The classification system tested consists of three qualifiers ranging from excellent to low quality vitrinites with an additional option for unsuitable vitrinites. This paper reports on the results obtained by 22 analysts who were asked to measure random reflectance readings on vitrinite particles assigning to each reading a qualifier. Four samples containing different organic matter types and a variety of vitrinite occurrences have been analysed. Results indicated that the reflectance of particles classified as excellent, good or poor compared to the total average reflectance did not show trends to be systematically lower or higher for the four samples analysed. The differences in reflectance between the qualifiers for any given sample were lower than the scatter of vitrinite reflectance among participants. Overall, satisfactory results were obtained in determining the reflectance of vitrinite in the four samples analysed. This was so for samples having abundant and easy to identify vitrinites (higher plant-derived organic matter) as well as for samples with scarce and difficult to identify particles (samples with dominant marine-derived organic matter). The highest discrepancies were found for the organic-rich oil shales where the selection of the vitrinite population to measure proved to be particularly difficult. Special instructions should be provided for the analysis of this sort of samples. The certainty of identification of the vitrinite associated with the vitrinite reflectance values reported has been assessed through a reliability index which takes into account the number of readings and the coefficient of variation. The same statistical approach as that followed in the ICCP vitrinite reflectance accreditation program for single seam coals has been used for data evaluation. The results indicated low to medium dispersion for 17 out of 22 participants. This, combined with data from other sets of comparative analyses over a long period, is considered an encouraging result for the establishment of an accreditation program on vitrinite reflectance measurements in dispersed organic matter.  相似文献   

14.
The study area is the southern depocenter (depth > 4200 m) of the Mesohellenic Basin which extends between Kipourio and Grevena, central Greece. The Mesohellenic Basin is a Middle-Tertiary intramontane basin developed within the Hellenide orogen. Previous studies have focused on the depositional environments, configuration and hydrocarbon potential of the basin. In this paper we present additional geochemical and petrographic data from outcrop samples of the basin's southern depocenter, which is considered the most promising area, in terms of hydrocarbon prospectivity. A total number of thirty six samples were analysed: Rock-Eval pyrolysis, maceral analysis, vitrinite reflectance and thermal alteration index, bitumens extraction, liquid chromatography, and GC-MS. The samples were collected from deltaic deposits and submarine fan sediments of Late Eocene to Late Oligocene age. The TOC values of the analysed samples range between rich and very rich and the organic matter consists mainly of type III kerogen and the organic matter consider to be predominately gas prone. The thermal maturity assessed from Tmax and vitrinite reflectance shows an immature stage of the organic matter along with the presence of layers having reached the very early mature stage. Vitrinite reflectance measurements and maturity calculations (applying the Lopatin modeling), reveal that the lower part of the depocenter sediments falls within the ‘oil window’. The extractable organic matter (EOM) (mg bitumens/g TOC) indicate the existence of samples (from deltaic deposits) with high ratio of transformation (EOM) (> 100 mg bitumen/g TOC). The GC and GC-MS analyses of the biomarkers indicate mainly the occurrence of terrestrial organic matter reflecting oxidizing conditions and both immature and very early mature stages. The results of the Rock-Eval pyrolysis and the distribution of the isoprenoids support the assumption of the input of an organic matter mixture.  相似文献   

15.
Ten samples from the Upper Jurassic Naokelekan and Barsarin Formations in an outcrop section near Sargelu Village were studied to evaluate their thermal maturity using vitrinite reflectance method. The studied beds appeared to be mature and within the oil generation window (0.79–1.25 % vitrinite reflectance in immersion oil (Ro)). Some of the reflectance histograms showed bimodal distribution indicating existence of nonindigenous populations which were all ignored during the measurements of the mean value of Ro. Comparison between the results obtained from vitrinite reflectance method and some other methods like pyrolysis and gas chromatography showed variations which finally more reality believed to be for the vitrinite reflectance method.  相似文献   

16.
刘曼丽  高福红  徐文 《世界地质》2016,35(1):184-190
为确定东岭鼻状构造带沙河子组烃源岩的发育程度,本文应用有机地球化学分析方法,对沙河子组的暗色泥岩进行了有机质丰度、类型和成熟度的研究。研究结果显示:有机碳平均含量为2.21%,生烃潜量平均值为9.13 mg/g,氯仿沥青"A"含量0.5%,总烃含量500×10~(-6),说明沙河子组暗色泥岩有机质丰度较高;有机显微组分中惰质组分含量较低,"壳质组+腐泥组"相对含量远远高于镜质组和惰质组。T_(max)为446℃~462℃,结合T_(max)与氢指数和降解指数的关系,指示有机质干酪根类型以II1~I型为主;镜质体反射率(Ro)为0.56%~0.71%,处于低成熟-成熟阶段。综合分析认为沙河子组烃源岩有机质丰度高,有机质类型好,有机质成熟度处于低成熟-成熟阶段,属于中等-好的烃源岩,以生油为主。东岭断鼻构造带沙河子组具有较大的勘探潜力。  相似文献   

17.
镜质体反射率的演化并不是人们传统意义上认为的随着温度(深度)的增加成指数增加,而是分阶段演化的。通过对有机质热模拟实验数据和自然演化数据进行分析后发现镜质体反射率的演化可以分为明显的3段:1)缓慢变化阶段,随着温度的增加镜质体反射率缓慢地变化,2)中等快速阶段,随着温度的增加镜质体反射率相比较前一阶段增加速率有明显的加大,3)快速增加阶段,随着温度的增加镜质体反射率呈指数快速增加。这种分阶段的演化是由镜质体本身的化学组成和化学结构所决定的。镜质体反射率演化阶段的划分对于热历史的恢复以及认识镜质体的热演化机制和规律具有重要的意义。  相似文献   

18.
选择库车坳陷和雅布赖盆地两个烃源岩热演化系列,在GC/MS分析的基础上探讨了二苯并噻吩类成熟度参数,如MDR4、MDR23、MDR、MDR’等的热演化特征,首次提出利用甲基二苯并噻吩分布指数(MDBI)作为研究区有效的新型成熟度标尺。结果表明,在成熟至高成熟阶段MDR4和MDR23主要受热力作用控制,在研究区应用效果良好;MDR在较高热演化阶段变化速率显著增加,而且适合于Ⅱ2和Ⅲ型有机质。甲基二苯并噻吩分布指数与其他有效参数,如Ro、tmax和MPI等之间的相关系数矩阵进一步证实,在Ro=0.67%~1.22%范围内,MDBI能够准确提供烃源岩热演化历史方面的信息。该指数的提出还有望为原油热成熟度的判识提供一个新的途径。  相似文献   

19.
Based on studies of the reflectance of Ordovician and Silurian zooclasts from 11 sections around the Huangling Anticline, Hubei, China, combined with determination of the conodont colour alteration indices (CAI) and of infrared spectroscopy of dispersed organic matter from the same or adjacent horizons, it is further proved that reflectances of graptolites, chitinozoans and scolecldonts, like vitrinite and natural bitumen, increase with increasing maturation, but follow different reflectance paths. They may be used, therefore, as thermal maturation indicators. Graptolites display optically strong anisotropy. The maximum reflectance measured from graptolite on polished section cut parallel to the bedding plane is the most suitable for determination of maturation of their host rocks. In polished section chitinozoan and scolecodont show reflectance, but no bireflectance owing to their isotropy. The random reflectance of chitinozoans is higher than that of scolecodonts in the case of the same maturity. By analysing the distribution trends of graptolite, chitionzoan and scolecodont reflectances, the Ordovician and Silurian strata can be subdivided into three areas of maturation in the present region. The potential of oil or gas generation is discussed for each area. The result is basically coincident with the distribution pattern of regional organic maturation presented by CAI and infrared spectroscopic determination of organic matter.  相似文献   

20.
Based on gas chromatography and gas chromatography mass spectrometry techniques, the authors examined biomarker characteristics of the Ganquan Formation source rocks in the area of Dahulishan, Ejina, and analyzed the information and petroleum geological significance that were indicated by the source of organic matter, sedimentary environment and maturity and so on. Gas chromatography peak of saturated hydrocarbons from the Ganquan Formation source rocks showed "the former peak" of the single peak distribution, the main peak of carbon being C18 , indicating the main sources of organic matter with marine organic matter. Pr/Ph ranges from 0.3 to 0.6, indicating a strongly reducing sedimentary environment. Biomarker assemblages of the Ganquan Formation source rocks are abundant in tricyclic terpane with long side chains, with a high level of gammacerane, showing dominant distribution of C27 sterane. High contents of gammacerane in organic matter show organic facies of source rocks in the saltwater sedimentary environment. That average hopane/sterane ratio is 0.59, showing that algae have made more contributions to organic matter than bacteria. And the high level of C27 steranes shows that algae are the main source of hydrocarbon precursors. The Ganquan Formation’s methylphenanthrene index, which is an effective molecular parameter index to measure thermal evolution of organic matter, ranges from 0.35 to 0.50, and the conversion of vitrinite reflectance Rc from it is within the range of 2.00-2.09, indicating that the Ganquan Formation source rocks are in the over-mature stage of thermal evolution.  相似文献   

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