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1.
Harold C. Helgeson Laurent Richard William F. McKenzie Alexandra Schmitt 《Geochimica et cosmochimica acta》2009,73(3):594-7350
Thermodynamic calculations and Gibbs free energy minimization computer experiments strongly support the hypothesis that kerogen maturation and oil generation are inevitable consequences of oxidation/reduction disproportionation reactions caused by prograde metamorphism of hydrocarbon source rocks with increasing depth of burial.These experiments indicate that oxygen and hydrogen are conserved in the process.Accordingly, if water is stable and present in the source rock at temperatures ?25 but ?100 °C along a typical US Gulf Coast geotherm, immature (reduced) kerogen with a given atomic hydrogen to carbon ratio (H/C) melts incongruently with increasing temperature and depth of burial to produce a metastable equilibrium phase assemblage consisting of naphthenic/biomarker-rich crude oil, a type-II/III kerogen with an atomic hydrogen/carbon ratio (H/C) of ∼1, and water. Hence, this incongruent melting process promotes diagenetic reaction of detritus in the source rock to form authigenic mineral assemblages.However, in the water-absent region of the system CHO (which is extensive), any water initially present or subsequently entering the source rock is consumed by reaction with the most mature kerogen with the lowest H/C it encounters to form CO2 gas and a new kerogen with higher H/C and O/C, both of which are in metastable equilibrium with one another.This hydrolytic disproportionation process progressively increases both the concentration of the solute in the aqueous phase, and the oil generation potential of the source rock; i.e., the new kerogen can then produce more crude oil.Petroleum is generated with increasing temperature and depth of burial of hydrocarbon source rocks in which water is not stable in the system CHO by a series of irreversible disproportionation reactions in which kerogens with higher (H/C)s melt incongruently to produce metastable equilibrium assemblages consisting of crude oil, CO2 gas, and a more mature (oxidized) kerogen with a lower H/C which in turn melts incongruently with further burial to produce more crude oil, CO2 gas, and a kerogen with a lower H/C and so forth.The petroleum generated in the process progresses from heavy naphthenic crude oils at low temperatures to mature petroleum at ∼150 °C. For example, the results of Computer Experiment 27 (see below) indicate that the overall incongruent melting reaction in the water-absent region of the system C-H-O at 150 °C and a depth of ∼4.3 km of an immature type-II/III kerogen with a bulk composition represented by C292H288O12(c) to produce a mature (oxidized) kerogen represented by C128H68O7(c), together with a typical crude oil with an average metastable equilibrium composition corresponding to C8.8H16.9 (C8.8H16.9(l)) and CO2 gas (CO2(g)) can be described by writing
(A) 相似文献
2.
Hydrous pyrolysis (HP) experiments were used to investigate the petroleum composition and quality of petroleum generated from a Brazilian lacustrine source rock containing Type I kerogen with increasing thermal maturity. The tested sample was of Aptian age from the Araripe Basin (NE-Brazil). The temperatures (280–360 °C) and times (12–132 h) employed in the experiments simulated petroleum generation and expulsion (i.e., oil window) prior to secondary gas generation from the cracking of oil. Results show that similar to other oil prone source rocks, kerogen initially decomposes in part to a polar rich bitumen, which decomposes in part to hydrocarbon rich oil. These two overall reactions overlap with one another and have been recognized in oil shale retorting and natural petroleum generation. During bitumen decomposition to oil, some of the bitumen is converted to pyrobitumen, which results in an increase in the apparent kerogen (i.e., insoluble carbon) content with increasing maturation.The petroleum composition and its quality (i.e., API gravity, gas/oil ratio, C15+ fractions, alkane distribution, and sulfur content) are affected by thermal maturation within the oil window. API gravity, C15+ fractions and gas/oil ratios generated by HP are similar to those of natural petroleum considered to be sourced from similar Brazilian lacustrine source rocks with Type I kerogen of Lower Cretaceous age. API gravity of the HP expelled oils shows a complex relationship with increasing thermal maturation that is most influenced by the expulsion of asphaltenes. C15+ fractions (i.e., saturates, aromatics, resins and asphaltenes) show that expelled oils and bitumen are compositionally separate organic phases with no overlap in composition. Gas/oil ratios (GOR) initially decrease from 508–131 m3/m3 during bitumen generation and remain essentially constant (81–84 m3/m3) to the end of oil generation. This constancy in GOR is different from the continuous increase through the oil window observed in anhydrous pyrolysis experiments. Alkane distributions of the HP expelled oils are similar to those of natural crude oils considered to be sourced from similar Brazilian lacustrine source rocks with Type I kerogen of Lower Cretaceous age. Isoprenoid and n-alkane ratios (i.e., pristane/n-C17 and phytane/n-C18) decrease with increasing thermal maturity as observed in natural crude oils. Pristane/phytane ratios remain constant with increasing thermal maturity through the oil window, with ratios being slightly higher in the expelled oils relative to those in the bitumen. Generated hydrocarbon gases are similar to natural gases associated with crude oils considered to be sourced from similar Brazilian lacustrine source rocks with Type I kerogen of Lower Cretaceous, with the exception of elevated ethane contents. The general overall agreement in composition of natural and hydrous pyrolysis petroleum of lacustrine source rocks observed in this study supports the utility of HP to better characterize petroleum systems and the effects of maturation and expulsion on petroleum composition and quality. 相似文献
3.
There are abundant bitumens and oil seepages stored in vugs in a Lower-Triassic Daye formation (T1d) marlite in Ni’erguan village in the Southern Guizhou Depression. However, the source of those oil seepages has not been determined to date. Multiple suites of source rocks of different ages exist in the depression. Both the oil seepages and potential source rocks have undergone complicated secondary alterations, which have added to the difficulty of an oil-source correlation. For example, the main source rock, a Lower-Cambrian Niutitang Formation (?1n) mudstone, is over mature, and other potential source rocks, both from the Permian and the Triassic, are still in the oil window. In addition, the T1d oil seepages underwent a large amount of biodegradation. To minimize the influence of biodegradation and thermal maturation, special methods were employed in this oil-source correlation study. These methods included catalytic hydropyrolysis, to release covalently bound biomarkers from the over mature kerogen of ?1n mudstone, sequential extraction, to obtain chloroform bitumen A and chloroform bitumen C from the T1d marlite, and anhydrous pyrolysis, to release pyrolysates from the kerogen of T1d marlite. Using the methods above, the biomarkers and n-alkanes released from the oil samples and source rocks were analysed by GC–MS and GC-C-IRMS. The oil-source correlation indicated that the T1d oil seepage primarily originated from the ?1n mudstone and was partially mixed with oil generated from the T1d marlite. Furthermore, the seepage also demonstrated that the above methods were effective for the complicated oil-source correlation in the Southern Guizhou Depression. 相似文献
4.
To determine the origin, maturity, formation mechanism and secondary process of marine natural gases in Northeastern Sichuan area, molecular moieties and carbon isotopic data of the Carboniferous and Triassic gases have been analyzed. Typical samples of marine gas precursors including low-maturity kerogen, dispersed liquid hydrocarbons (DLHs) in source rocks, residual kerogen and oil have been examined in a closed system, and several published geochemical diagrams of gas origins have been calibrated by using laboratory data. Results show that both Carboniferous and Triassic gases in the study area have a thermogenic origin. Migration leads to stronger compositional and weak isotopic fractionation, and is path dependent. Carboniferous gases and low-H2S gases are mainly formed by secondary cracking of oil, whereas high-H2S gases are clearly related to the TSR (Thermal Sulfate Reduction) process. Gases in NE Sichuan show a mixture of heavy (13C-enriched) methane in comparison to the lower maturated ethane of Triassic gas samples, suggesting a similar source and maturity for ethane and propane of Carboniferous gases, and a mixture of heavy ethane to the propane for Triassic gases. Based on the data plotted in the diagram of Chung et al. (1988), the residual kerogen from Silurian marine shale and palaeo oil reservoirs are the main source for Carboniferous gases, and that the residual kerogen from Silurian and Permian marine rocks and Permian paleao oil reservoirs constitute the principal source of Triassic gases. 相似文献
5.
《Applied Geochemistry》1988,3(5):441-453
Green River shale (Type I kerogen), Yaamba shale (Type II kerogen) and Sarufutsu coal (Type III kerogen) were heated to various temperatures using Rock-Eval. The amount of hydrocarbons generated and weight loss by pyrolysis were measured to obtain a better understanding of petroleum generation. After the pyrolysis experiments, elemental analysis (C, H), vitrinite reflectance (%Ro) measurement, maceral observation, infrared spectroscopy (IR) and13C-NMR spectroscopy were carried out on the coal samples. Changes in H/C atomic ratio, IR and NMR spectra indicate that experiments by Rock-Eval resemble those of the natural evolution of kerogen. However, the petrographic changes of the coal show more similarity to coal liquefaction and coking than to natural coalification. Changes in the amount of generated hydrocarbons with increasing maturation show that Type II kerogen produces more hydrocarbons than does Type I when Ro does not exceed 1.1%. Petroleum generation curves for the three samples were concordant with trends in natural systems, and a conceptual model of petroleum generation curve classified into three types is proposed, namely (1) curve of total amount enerated, (2) curve of generation rate, and (3) curve of fluid composition. Changes of IR and NMR spectra after pyrolysis imply that generated hydrocarbons are derived from aliphatic C structures of kerogen macromolecules. Moreover, the difference in genetic potential between Type I and Type III reflects different amounts of aliphatic structures. Type I is assumed to have a simple assemblage (mainly polymethylene carbons), and Type III is assumed to have a more complex variety of structures that are responsible for the difference in generation rates between the two kerogen Types. A quantitative analysis of C species of various bond structure by13C-NMR confirms that petroleum generation is the process of bond cleavage of kerogen macromolecules; lower-energy bonds decrease at an earlier stage of reaction, while aromatic carbons with higher bond energies survive to form graphitic structure at postmature stages. Emphasis is placed on the idea that the most important and direct factor in petroleum generation is a change in the molecular structure of kerogen with increasing maturation. NMR and other methods providing information about molecular structures of kerogen will become strong tools for evaluating source rocks and sedimentary basins in the future. 相似文献
6.
A. Šajnović K. Stojanović V. Simić G. S. Pevneva A. K. Golovko B. Jovančiećević 《Geochemistry International》2011,49(10):1022-1034
Liquid thermolysis products of various types of immature kerogen from sedimentary lacustrine rocks from the Valjevo-Mionica
basin in Serbia were studied to evaluate the generation potential of kerogen contained in the organic matter (OM) of the rocks,
determine the composition of the biomarkers and alkylaromatics in the liquid thermolysis products, and elucidate the effect
of Pt4+ and Ru3+ ions (which were added in the form of inorganic salts) on the yield and hydrocarbon composition of the liquid thermolysis
products. For this purpose, representative bitumen-free samples A and B of the sedimentary rocks were subjected to thermolysis
under various conditions. Rock A contains high amount of immature organic matter, which is dominated by kerogen type I/II
and was generated under strongly reduced sedimentation conditions at a high salinity. Sample B is poorer in immature OM than
sample A, and the OM of the former contains kerogen type II/III and was generated predominantly in a reduced environment.
The content of the liquid products and the concentrations of hydrocarbons obtained in the course of thermolysis of bitumen-free
sample A and the typical oil distribution of the biomarkers and alkylaromatics in the thermolysis products confirm a high
generation potential of OM in this rock. In all of our experiments on the thermolysis of bitumen-free sample B, the yield
of liquid products and hydrocarbons is low. According to the kerogen type, the thermolysis of this rock generates much gases.
The Pt4+ and Ru3+ ions (added in the form of simple inorganic salts) increased the yield of liquid (kerogen type I/II) and gaseous (kerogen
type II/III) products. During the thermolysis of various type of immature kerogen in the lacustrine sedimentary rocks at a
temperature of 400°C, the OM attained maturation corresponding to the early catagenesis level. Saturated biomarkers and alkylaomatics
in the thermolysis products of both samples display typical oil distributions. The type of the source OM most strongly affects
the composition of n-alkanes and alkylnaphthalenes. The metal ions used in this research served as catalysts for the methylation process during
the thermolysis of immature kerogen, regardless of its type. The effect of the Pt4+ and Ru3+ ions on other transformations of the hydrocarbons, for example, the destruction of high-molecular n-alkanes to low-molecular ones and on isomerization reactions in molecules of polycyclic biomarkers and alkylaromatics to
thermodynamically more stable isomers in the thermolysis products is controlled, first of all, by the type of the source OM. 相似文献
7.
东营凹陷牛38井沙河街组三段烃源岩从沙三下亚段向沙三中-上亚段为一从高水位深湖相向低水位前三角洲相发展的沉积旋回,该沉积环境控制从下向上发育不同类型的有机质。相应地,该段烃源岩品质从下向上变差,其中沙三中亚段上部及沙三中亚段中部烃源岩产烃能力小,沙三下亚段烃源岩整体品质好,局部存在优质烃源岩。其优劣性体现了在该段烃源岩中,Ⅰ型干酪根具有高的生产力,而Ⅲ型、Ⅱ2型干酪根生烃潜力很低,基本为无效有机质。计算结果显示不同数据点的烃源岩单位质量原始生烃潜量可相差3个数量级,体现了烃源岩存在强烈的非均质性。有机碳的非均质性分布为其提供了物质基础,而湖盆的旋回式沉积及湖平面的波动性变化是其内在原因。同时,本文也提供一种计算生排烃量的新方法,结果表明该方法较为有效可行。 相似文献
8.
随着色谱-质谱联用技术的引用,对原油及岩石抽提有机质开展了生物标志物的研究,使我们对陆相沉积岩中有机质的认识,深入到单烃化合物及其分子结构中了。这将使我们准确地鉴别出陆相沉积中特征有机化合物,对探讨石油起源、演化、运移等较复杂的地球化学问题,提供了可靠的信息,更好的为石油地质勘探服务。 相似文献
9.
Joseph A. Curiale 《Organic Geochemistry》1988,13(4-6)
Molecular markers have considerable promise as thermal maturation indicators in source rocks having a well-defined depositional environment. This occurs in the Kishenehn Formation (northwest Montana and southeast British Columbia), an Oligocene unit comprised of fluvial and lacustrine shales. Up to 3 km of these non-marine sediments were deposited in a 900 sq.km elongated half graben atop the Precambrian rocks of the Lewis Thrust sheet. Specific outcrops of the Coal Creek Member of the Kishenehn Formation are known to contain excellent potential source rocks, including extensive oil shales. The source rock potential and molecular marker geochemistry of most of the major Kishenehn outcrops have now been investigated, and regional results are presented in this paper.source rock analysis of a regional suite of Kishenehn samples indicates excellent petroleum potential (immature Type I kerogen) throughout the basin. Several classes of distinctive diagenetic molecular markers occur within the Coal Creek Member of the Kishenehn Formation, including diasterenes, spirosterenes, methylspirosterenes, B-ring monoaromatic anthrasteroids, ββ-hopanes and moretanes. Molecular markers indicative of non-marine deposition include dehydroabietane (conifer input) and an onocerane recently identified in leaf fossils of Miocene lacustrine beds in adjacent Idaho. Triterpane ratios are significantly more sensitive than vitrinite reflectance methods in assessing thermal maturation in the Kishenehn, and are successfully used in this study to order outcrop locations according to thermal maturity level. The systematic variation of specific markers with increasing thermal maturation suggests that molecular correlation is feasible, and could provide a method of assessing stratigraphic continuity in the basin. 相似文献
10.
Chunfang Cai Kaikai Li Ma Anlai Chunming Zhang Zhiming Xu Richard H. Worden Guanhui Wu Baoshou Zhang Lixin Chen 《Organic Geochemistry》2009,40(7):755-768
The reported source rocks for the abundant petroleum in the Tarim Basin, China range from Cambrian to Lower Ordovician and/or Upper Ordovician in age. However, the difference between the two groups of source rocks is not well characterized. In this study, pyrite was removed from eleven mature to over mature kerogen samples from source rocks using the method of CrCl2 reduction and grinding. The kerogen and coexisting pyrite samples were then analyzed for δ34S values. Results show that the kerogen samples from the Cambrian have δ34S values between +10.4‰ and +19.4‰. The values are significantly higher than those from the Lower Ordovician kerogen (δ34S of between +6.7‰ and +8.7‰), which in turn are generally higher than from the Upper Ordovician kerogen samples (δ34S of between ?15.3 and +6.8‰). The associated pyrite shows a similar trend but with much lower δ34S values. This stratigraphically controlled sulfur isotope variation parallels the evolving contemporary marine sulfate and dated oil δ34S values from other basins, suggesting that seawater sulfate and source rock age have an important influence on kerogen and pyrite δ34S values. The relatively high δ34S values in the Cambrian to Lower Ordovician source rocks are associated with abundant aryl isoprenoids, gammacerane and C35 homohopanes in the extractable organic matter, indicating that these source rocks were deposited in a bottom water euxinic environment with water stratification. Compared with the Upper Ordovician, the Cambrian to Lower Ordovician source rocks show abundance in C28 20R sterane, C23 tricyclic terpanes, 4,23,24-trimethyl triaromatic dinosteroids and depletion in C24 tetracyclic terpane, C29 hopane. Thus, δ34S values and biomarkers of source rock organic matter can be used for distinguishing the Cambrian and Upper Ordovician source rocks in the Tarim Basin. 相似文献
11.
A preliminary assessment of the source potential of the Jurassic section was obtained using organic geochemical data on samples collected from outcrops on Franz Josef Land and Svalbard archipelagoes as well as boreholes in the Barents Sea basin. The presence of organic-rich shale units with good source potential was reported for the first time within the studied section of Early to Middle Jurassic age, along with well-documented Upper Jurassic source rocks. The study provides an assessment of regional variations in the kerogen type, hydrocarbon generation potential, and maturation of organic matter from Jurassic sediments. 相似文献
12.
Joel S. Leventhal 《Chemical Geology》1976,18(1):5-20
Stepwise pyrolysis-gas chromatography is used to examine and characterize the carbonaceous matter in sedimentary rocks. Low-temperature steps remove material normally volatile or extracted by benzene-methanol. Successively-higher temperature steps degrade the insoluble carbonaceous matter (kerogen) into smaller molecular pieces. The sequential pyrolysis steps have the advantage of breaking the kerogen at several temperatures which may be related to bond type or strength. The pyrolysis product chromatograms from each step can be compared. The molecular sizes (chain length) of kerogens fragments can be determined. The results presented here show the molecules in the range C11 to C23 because: (1) they can be compared to normal petroleum source rock extractables; and (2) these large molecules give a feeling for the molecular construction of the kerogen.Green River and Antrim shales show low-temperature material which is indigenous and not modified compared to the pyrolyzed kerogen fragments in the range C11C23. Kupferletten shows low-temperature material of a narrow molecular weight range of C15C19 which is probably derived from the kerogen. Monterey shale low-temperature material appears to be unrelated to the kerogen as represented by its pyrolysis products. The Pierre shale kerogen shows molecules over the range C11C23. Kerogen from the Romney shale has no molecules large than C8 in its pyrolysis products and no petroleum potential due to thermal and tectonic diagenesis. 相似文献
13.
烃源岩中矿物沥青基质成烃潜力探讨 总被引：4，自引：1，他引：4
烃源岩中存在大量矿物沥青基质，目前对其成烃潜力知之甚少。本文以酒东盆地侏罗系和白垩系烃源岩为例，从矿物沥青基质与有机显微组分，无机矿物、有机质丰度、有机质类型，有机质成熟度的关系及其荧光变化特点探讨其组成及成烃潜力，结果表明，矿物沥青基质中有机质含量低，且以次生有机质为主，原生有机质含量较少，成烃潜力有限。 相似文献
14.
《International Geology Review》2012,54(13):1508-1521
Twenty Cretaceous shale samples from two wells in the Orange Basin of South Africa were evaluated for their source rock potential. They were sampled from within a 1400 m-thick sequence in boreholes drilled through Lower to Upper Cretaceous sediments. The samples exhibit total organic carbon (TOC) content of 1.06–2.17%; Rock-Eval S2 values of 0.08–2.27 mg HC/g; and petroleum source potential (SP), which is the sum of S1 and S2, of 0.10–2.61 mg HC/g, all indicating the presence of poor to fair hydrocarbon generative potential. Hydrogen index (HI) values vary from 7 to 128 mg HC/g organic carbon and oxygen index (OI) ranges from 37 to 195 mg CO2/g organic carbon, indicating predominantly Type III kerogen with perhaps minor amounts of Type IV kerogen. The maturity of the samples, as indicated by T max values of 428–446°C, ranges from immature to thermally mature with respect to oil generation. Measured vitrinite reflectance values (%Ro) of representative samples indicate that these samples vary from immature to mature, consistent with the thermal alteration index (TAI) (spore colour) and fluorescence data for these samples. Organic petrographic analysis also shows that amorphous organic matter is dominant in these samples. Framboidal pyrite is abundant and may be indicative of a marine influence during deposition. Although our Rock-Eval pyrolysis data indicate that gas-prone source rocks are prevalent in this part of the Orange Basin, the geochemical characteristics of samples from an Aptian unit at 3318 m in one of the wells suggest that better quality source rocks may exist deeper, in more distal depositional parts of the basin. 相似文献
15.
通过对研究区露头烃源岩样品进行Rock-Eval热解模拟实验、干酪根镜鉴、镜质体反射率、族组分分离、单体烃碳同位素等分析,对北羌塘盆地光明湖地区侏罗系白龙冰河组烃源岩有机质特征进行研究。结果表明,该区白龙冰河组烃源岩以碳酸盐岩为主,有机碳含量0.01%~1.21%,平均值为0.39%,有机质丰度较高;干酪根显微组分以腐泥组为主,含量70%~92%,平均值为80%,以Ⅱ1型为主,主峰碳、(nC21-/ nC22+)轻/重比及Pr/nC17-Ph/nC18的相关图均表明有机质来自低等水生生物,有机质类型较好;镜质体反射率最小值1.409%,最大值2.423%,平均值为1.909%,有机质的热演化程度总体较高,达到高成熟-过成熟阶段。 相似文献
16.
Mineral-bituminous matrix(MBM) makes up a major part of source rocks,but its potential in hydrocarbon generation is uncertain,Mineral and organic (Maceral and kerogen) compositions,organic maturity and fluorescence of MBM are studied based on source rock samples from eastern Jiuquan(Jiudong)Basin.The results show that MBM is dominated by inorganic minerals and among the small percentage of organic components those of secondary origins are predominant over the primary species.This strongly indicates that the significance of MBM in hydrocarbon generation is limited. 相似文献
17.
海相烃源岩二次生烃潜力定量评价新方法 总被引：1，自引：0，他引：1
烃源岩二次生烃的演化过程是残余干酪根热解演化与残留油热裂解转化两个既相互联系又完全不同的物理化学反应过程的叠加。本文利用自制高压釜热压生烃模拟实验装置,采取分阶段连续递进模拟实验方式,以海相烃源岩样品为例分别评价了残余干酪根的生烃潜力与残留可溶有机质转化油气潜力,建立了一套不同起始与终止成熟度海相烃源岩二次生烃潜力的定量评价方法,并首次明确提出了干酪根生油指数KIo、干酪根生气指数KIg、干酪根生烃指数KIh等评价烃源岩生烃潜力的参数,弥补了ROCK EVAL热解评价方法无法分别评价烃源岩在不同生烃演化阶段所生成的“油”或“烃气”潜力的不足。 相似文献
18.
东濮凹陷北部盐湖相膏盐岩极其发育,膏盐岩对烃源岩性质及生烃特征的影响研究薄弱。采用地质与地球化学相结合途径,探讨了含膏盐岩层系烃源岩特性及其成烃演化规律。结果表明,盐区与无盐区烃源岩的特性有很大差异,北部盐湖相含盐区深灰色、褐色等暗色页岩有机质丰度一般大于15%,有机质类型以Ⅱ1型和Ⅰ型为主,是区内主要的优质烃源岩;南部淡水湖相无盐区主要发育有利生气的Ⅱ—Ⅲ型干酪根,反映东濮凹陷烃源岩的质量及生烃潜能与膏盐岩的发育密切相关。观察到膏盐岩影响烃源岩的成烃演化进程,当膏盐层厚度为50 m时,生油窗的范围显著增加;随着盐岩厚度(>50 m)的增加,湿气窗的范围也逐渐增加;当膏盐岩厚度约400 m时,生油窗范围开始减小,湿气窗的范围仍有增加趋势。膏盐岩对烃源岩“生油气窗”的影响是基于其较高的热导率属性,通过影响地温场而实现。以地质解剖为依据,建立了文留地区含膏盐岩层系烃源岩成烃演化模式。东濮凹陷含膏盐岩层系烃源岩的演化特征对该凹陷及同类含膏盐岩盆地油气勘探具有重要指示意义。 相似文献
19.
湘中坳陷上古生界碳酸盐岩烃源岩特征及生烃模式 总被引：1，自引：0，他引：1
据野外露头观察和采样分析,湘中坳陷上古生界碳酸盐岩烃源岩以泥质灰岩、泥灰岩和石灰岩为主,生油母质以偏泥型为主,烃源岩的沉积厚度大、分布范围广,并具有有机碳丰度高、样品达标率高、热演化程度高的"三高"特点。在对碳酸盐岩烃源岩热演化研究的基础上总结出生烃模式,认为本区的生烃分为原始沥青解聚成烃、干酪根降解成烃、包裹有机质释放成烃和热裂解气共四个成烃阶段。 相似文献
20.
不同类型烃源岩气态烃的生成特征研究--来自差热-色谱联机热模拟实验方法的证据 总被引：2，自引：0，他引：2
运用差热-色谱联机分析仪对不同煤阶的标准煤样及泥岩和碳酸盐岩烃源岩的热模拟研究表明,低成熟的煤具有更强的放热反应和较大的失重量,其放热反应第一峰温度和失重温度相对较低。低煤阶煤在热模拟过程中比高煤阶煤具有更强的生烃能力。烃源岩气态烃的生成量和特征不仅受控于烃源岩中有机质的丰度而且与其岩石类型、干酪根类型、成熟度等存在着密切关系。成熟度较高的烃源岩属耗尽了的烃源岩,其生烃能力相对较弱。含Ⅰ、Ⅱ型干酪根烃源岩生成的气态烃中重组分含量普遍较高,含Ⅲ型干酪根烃源岩生成的气态烃中甲、乙烷等轻组分含量普遍较高。碳酸盐岩烃源岩在热模拟的高温阶段往往能生成比较大量的气态烃。 相似文献