歧口凹陷未熟-低熟烃源岩生烃组分研究

有机岩石学全岩分析结果表明,歧口凹陷未熟-低熟烃源岩中显微组分含量平均占全岩体积的4.64%,矿物沥青基质含量相对偏低。显微组分中富含腐泥组,惰质组含量很低,相对发育壳质组和镜质组,具有藻类等低等水生生物与高等植物混合生源的特点。藻类体是歧口凹陷主要的生烃组分,矿物沥青基质是歧口凹陷烃源岩中值得重视的生烃组分。     

黔南代页1井下石炭统打屋坝组页岩气地质条件及勘探前景

近年来发现黔南地区下石炭统打屋坝组发育厚度较大的黑色页岩层,该地层已经成为黔南地区重要的页岩气目标地层。为进一步了解该地层的页岩气参数,评价其页岩气勘探潜力,对代页1井打屋坝组黑色页岩进行观察和取样分析,显示该井打屋坝组黑色页岩钻厚为80 m,总体为一套深水陆棚相沉积; 干酪根显微组分以腐泥组、壳质组和镜质组为主,Ⅰ型-Ⅲ型干酪根均有发育,有机碳(TOC)含量主要分布在1.5%3.3%之间,镜质体反射率(R_o)为2.15%2.66%; 矿物组成以石英、黏土矿物为主,脆性矿物(不含方解石)含量在35%64%之间; 含气量在0.494.97 m³/t之间,平均为2.20 m³/t。通过露头剖面观察,显示黔南下石炭统打屋坝组黑色页岩厚度均较大,代页1井含气量较高,有机地化、储集物性参数较好,反映打屋坝组具有良好的勘探前景,可进一步加强该地层的基础地质、页岩储层改造和页岩气富集规律研究工作。     

Geochemical Characteristics and Sedimentary Control of Pinghu Formation (Eocene) Coal‐bearing Source Rocks in Xihu Depression,East China Sea Basin

Coal-bearing source rocks of the Pinghu Formation in the Xihu Depression comprise an important material basis of oil and gas resources in the East China Sea Basin.Based on drilling core observation results combined with the analysis and test results of macerals,trace/rare earth elements,and rock pyrolysis,the geochemical characteristics and sedimentary control of coal-bearing source rocks formation are discussed in a high-frequency sequence framework.The results indicate that the macerals composition of the coal-bearing source rocks of the Eocene Pinghu Formation in the Xihu Depression is dominated by vitrinite,with low-medium abundance of exinite and almost no inertinite.The coals and carbonaceous mudstones display higher amounts of total organic carbon(TOC)(14.90%-65.10%),S1+S2(39.24-136.52 mg/g),and IH(191-310 HC/g TOC)respectively,as compared to the mudstones.Organic matter is plotted in typeⅢkerogens and partially in typeⅡ;it is mainly in the low maturity stage.The trace elements results imply that the samples were deposited in a weakly reducing to weakly oxidizing environment and were occasionally affected by seawater.The coal-bearing source rocks were deposited in a relatively oxygen-containing environment.The coal-bearing source rocks development is jointly controlled by the coal accumulation environment,the water conditions affected by ocean currents in offshore basins in China,oxidation-reduction cycles of aqueous media and paleoclimate evolution in a high-frequency sequence framework.     

库车坳陷北部山前带中生界烃源岩有机岩石学

应用全岩有机岩石学分析方法,对库车坳陷北部山前带中生界三叠系和侏罗系烃源岩的显微组分、主要富氢组分、有机质类型及热演化程度进行了研究。结果表明：库车坳陷北部山前带侏罗系克孜勒努尔组烃源岩显微组分总含量最高,恰克马克组烃源岩最低。中生界烃源岩显微组分组成具有镜质组含量高、壳质组和惰性组相对发育、腐泥组贫乏的特征。不同层位具有一定差异性,克孜勒努尔组和塔里奇克组中镜质组含量较高,恰克马克组壳质组相对发育。孢子体、壳屑体、角质体和藻类体是其主要的富氢组分,恰克马克组富氢组分相对含量最高。烃源岩有机质类型以Ⅲ型和Ⅱ2型为主,有利于生气,镜质组反射率Ro为056%~187%,热演化程度处于成熟-高成熟阶段。克拉苏—依奇克里克构造带冲断前缘烃源岩显微组分总含量与热演化程度均相对较高,为烃源岩的最大成熟生烃中心。烃源岩高生烃潜力与高的壳质组含量和低的陆源有机质含量有关。     

Characteristics of hydrocarbon generation from organic macerals in Jurassic coal measures, Xinjiang, China

The Jurassic coals of the Junggar and Turpan-Hami basins, Xinjiang, China, are characterized by abundant vitrinite. Microscopic analysis of Junggar coal samples indicates that they contain desmocollinite and hydrogen-rich vitrinite with a low reflectivity. The hydrocarbon-generating potential of various macerais follows the decreasing order of exinite > vitrinite > inertinite. However, desmocollinite is a principal maceral for hydrocarbon generation in this area because the content of vitrinite is higher than that of exinite. Data from simulating experiments and infrared spectra show that the hydrocarbon-generating process occurred primarily at the lower-mature stage in the Middle-Lower Jurassic coal measures. Generally, crude oil from the Qigu oilfield has a close similarity in hopanoid distribution to the vitrinite and exinite from the Jurassic strata with C₂₃-C₃₂ pentacyclic triterpanes and γ-lupane being present. The distribution of steranes is also similar. C₂₉-sitostane is dominant and Q₂₇ ergostane is subordinate. Only a trace amount of cholestane is present. All this suggests that the crude oil from the Qigu oilfield was derived from Jurassic coal measures.     

The Late Triassic Callide Coal Measures, Queensland, Australia: Coal petrology and depositional environment

The Late Triassic (Carnian-Rhaetian) Callide Coal Measures are preserved in a partly fault-bounded basin remnant in east-central Queensland, Australia. The sequence comprises up to 150 m of interbedded clastic sedimentary rocks and at least four major coal seams, including one coal body up to 23 m thick. The sequence was deposited initially in high-gradient alluvial fan systems which gave way through time to sandy, low-sinuosity rivers. The restricted, intermontane and entirely alluvial nature of sediment accumulation is here considered to have influence the petrographic characteristics of Callide coals, and their external geometry.The main coal seam from the Callide Measures shows variation in the predominance of some macerals, indicating successions of environmental changes. The application of transmission electron microscopy (TEM) to the study of the Callide coal has enabled a better understanding of the nature and origin of some of the less understood macerals such as micrinite and vitrinite B. Two forms of vitrinite have been observed, each with a distinct reflectance range. The wood-sourced vitrinite A displays an average reflectance of 0.56%, implying a higher rank than the 0.49% Ro total vitrinite reflectance recorded in previous publications. Vitrinite B and A together represent the most commonly occurring macerals in the Callide coal samples of the present study. The lower-reflecting vitrinite B which forms bands, often several hundred μm in thickness, in TEM shows sub-micron electron transparent laminae of lipid-rich material alternating with a more conventional vitrinite material. The vitrinite B is interpreted to represent accumulations of leaves.The Callide coal has entered the oil window, and oil has been generated from some exinite, cutinite, and resinite, as evident from change in fluorescence and the presence of exsudatinite in cell cavities and cleats. Vitrinite B is seen under the microscope to also be generating oil. Micrinite, the origin of which has been much debated, occurs in selected horizons only, as lenticular bodies suggesting cell filling or filling of spaces between laminations in vitrinite B. TEM shows micrinite to consist predominantly of sub-micron pyrite and possibly other mineral particles adsorbed on humic acids.     

鄂尔多斯盆地延安组煤有机岩石学研究

鄂尔多斯盆地侏罗纪延安组煤系地层可否成为该盆地另一套油源岩的问题,历来存有争议。系统的煤岩和有机岩石学分析表明:煤中倾油性的壳质组分含量低,基质镜质体的类型也不利于生油,因此,延安组煤系有机质不大可能形成具有工业价值的煤成油藏     

PHYSICAL AND CHEMICAL PROPERTIES OF BITUMINOUS COAL CONSTITUENTS (MACERALS)

Investigation of bituminous-coal macerals, accomplished through the Institut für Brennstoff Chemie (Fuel Chemistry Institute) of Aachen, is summarized here. Coal from five Ruhr coal beds was processed to obtain pure macerals in quantities sufficient to study their individual structure and chemical composition. Vitrinite, micrinite and exinite were recovered accordingly, and their chemical and physical properties studied; detailed, graphical interpretation of these data has been included. Chemical composition is derived for vitrinite, exinite, micrinite, and fusinite individually. Chemical structure of the macerals is discussed in relation to aromatically bound carbon content. It has been possible thus far, to determine maceral properties with respect to coalification rank as well as to indicate differentiation of these properties in macerals from the same coal bed. --D. D. Fisher.     

The influence factors of gas-bearing and geological characteristics of Niutitang Formation shale in the southern margin of Xuefeng Mountain ancient uplift: A case of Well Huangdi 1

In order to evaluate the geological characteristics and gas-bearing factors of Niutitang Formation within the Lower Cambrian of northern Guizhou, the Huangping area located at the southern edge of the ancient uplift belt of Xuefeng Mountain was selected as the target area, and Well Huangdi 1 was drilled for the geological survey of shale gas. Through geological background analysis and well logging and laboratory analysis such as organic geochemical test, gas content analysis, isothermal adsorption, and specific surface area experiments on Well Huangdi 1, the results show that the Niutitang Formation is a deep-water shelf, trough-like folds and thrust fault. The thickness of black shale is 119.95 m, of which carbonaceous shale is 89.6 m. The average value of organic carbon content is 3.55%, kerogen vitrinite reflectance value is 2.37% and kerogen type is sapropel-type. The brittle mineral content is 51% (quartz 38%), clay mineral content is 38.3%. The value of porosity and permeability are 0.5% and 0.0014 mD, which the reservoir of the Niutitang Formation belongs to low permeability with characteristics of ultra-low porosity. The gas content is 0.09 −1.31 m³/t with a high-value area and a second high-value area. By comparing with the geological parameters of adjacent wells in the adjacent area, the accumulation model of “sediment control zone, R_o control zone, structure controlling reservoir” in the study area is proposed. Therefore, deep-water shelf-slope facies, R_o is between high maturity-early stage of overmaturity and well-preserved zones in the Niutitang Formation in this area are favorable direction for the next step of shale gas exploration.     

四川盆地五峰—龙马溪组黑色页岩有机岩石学特征研究

目前五峰—龙马溪组黑色页岩中显微组分缺乏统一的分类方案,命名也较为混乱,给页岩气勘探与评价造成了困难。为此,采用全岩光片和有机地球化学(TOC、δ¹³C_org)分析等方法,对四川盆地五峰—龙马溪组黑色页岩中显微组分进行有效识别与特征总结,探讨其可能成因,并判断其有机质类型。研究结果表明:五峰—龙马溪组页岩中显微组分主要由海相镜质组、腐泥组、动物有机碎屑组和次生组组成。其中,海相镜质组由无结构镜质体组成,呈浑圆状或长条状,具有强的光反射能力,但分布并不广泛;腐泥组主要由无结构腐泥体组成,为藻类遭受热降解过程而形成的无结构且无固定形态的显微组分,在富有机质页岩中广泛分布;动物有机碎屑组主要包括笔石表皮体、几丁虫和放射虫有机碎屑体;次生组由次生沥青体组成,广泛分布在页岩基质孔隙中,呈无固定形状。五峰—龙马溪组页岩中主要发育腐泥组和次生组,其次为动物有机碎屑组和海相镜质组,其有机质类型以Ⅰ-Ⅱ₁型干酪根为主,且腐泥组和次生组含量越高,有机质类型越好,其生烃潜力越大。     

鄂尔多斯盆地中部上古生界山西组页岩储层特征

鄂尔多斯盆地山西组发育一套厚度大且有勘探潜力的陆海陆过渡相页岩。应用岩芯观察、X衍射、扫描电镜和显微镜观察以及高压压汞等方法,对该盆地中部山西组页岩的岩石学、矿物学、页岩储集空间、孔隙结构和物性特征进行分析研究。结果表明:研究区山西组页岩以黑色泥岩、黑色页岩夹纹层或薄层状深色粉砂岩为主,页岩主要由黏土矿物和石英两类矿物组成,二者平均含量分别为59.6%和36.9%。页岩宏观和微观裂隙发育,显微镜下统计的显微裂缝平均面密度达到116.6/m。除了发育与矿物和成岩作用有关的矿物孔隙外,页岩中有机显微组分发育较多的有机质孔。页岩孔隙度平均为0.77%,渗透率平均为0.06×10-3 μm2。山西组页岩总有机碳（TOC）、镜质体反射率（R_o,%）和黏土矿物含量是影响页岩孔隙度的主要因素,具有正相关性,而石英含量与页岩孔隙度呈一定的负相关关系。山西组页岩中裂缝的普遍发育提高了页岩的渗透率,有利于页岩气聚集成藏。综合分析表明山西组页岩气储层地质条件一般,开发难度较大,但在裂缝发育、物性较好的层位和地区仍具有较好的页岩气资源前景。     

Hydrocarbon source rock potential evaluation of the Late Paleocene Patala Formation,Salt Range,Pakistan: Organic geochemical and palynofacies approach

Organic geochemical and palynofacies analyses were carried out on shale intervals of the Late Paleocene Patala Formation at Nammal Gorge Section, western Salt Range, Pakistan. The total organic carbon content and Rock-Eval pyrolysis results indicated that the formation is dominated by type II and type III kerogens. Rock-Eval \({T}_{\mathrm{max}}\) vs. hydrogen index (HI) and thermal alteration index indicated that the analysed shale intervals present in the formation are thermally mature. \(S_{1}\) and \(S_{2}\) yields showed poor source rock potential for the formation. Three palynofacies assemblages including palynofacies-1, palynofacies-2 and palynofacies-3 were identified, which are prone to dry gas, wet gas and oil generation, respectively. The palynofacies assessment revealed the presence of oil/gas and gas prone type II and type III kerogens in the formation and their deposition on proximal shelf with suboxic to anoxic conditions. The kerogen macerals are dominated by vitrinite and amorphinite with minor inertinite and liptinite. The kerogen macerals are of both marine and terrestrial origin, deposited on a shallow shelf. Overall, the dark black carbonaceous shales present within the formation act as a source rock for hydrocarbons with poor-to-moderate source rock quality, while the grey shales act as a poor source rock for hydrocarbon generation.     

Gas-generation potential of shales in small and medium-sized basins: a case study from the Xuanhua Basin,north China

Abstract

Small- and medium-sized basins are widely distributed, and some contain commercial gas reservoirs demonstrating their gas-generation potential. The Xuanhua Basin, which is a small-sized coal-bearing basin in north China, includes a promising target for shale-gas exploration in the Xiahuayuan Formation. In this study, we used this basin as a case study to assess the critical geochemical features for small or medium-sized basins to form commercial gas reservoirs. Total organic carbon (TOC) analysis, Rock-Eval pyrolysis, microscopic observation of macerals, vitrinite reflectance measurement and kerogen stable carbon isotope analysis were performed to characterise the organic geochemistry of the Xiahuayuan shales. The original total organic carbon (TOC_o) content and hydrocarbon-generative potential (S_2o) were reconstructed to further evaluate the gas-generation potential of these shales. In addition, geochemical data of shales from other similar-sized basins with gas discoveries were compared. The results showed that the kerogen from the Xiahuayuan Formation is Type III (gas-prone), and macerals are dominated by vitrinite. TOC values showed a strong heterogeneity in the vertical profiles, with most higher than 1.5?wt%. The measured R_o values ranged from 1.4 to 2.0%. However, thermal maturity was not correlated with the present-day burial depth with higher maturity in the wells closest to the diabase intrusion centre. The remaining generation potential (S₂) averaged 0.91?mg HC/g rock, equal to 1.4?cm³ CH₄/g rock, and the average amount of hydrocarbon generated was 4.33?cm³ CH₄/g rock. In small and medium-sized basins, the TOC content of commercially developed gas shales ranged from 0.5 to 2.5?wt%, organic matter was mainly humic (gas-prone), and the burial depth was generally shallow. Biogenic gas reservoirs for commercial exploitation tend to have larger shale thicknesses (120–800?m) than thermogenic gas reservoirs (60–90?m).

1. The Xiahuayuan Formation is a good gas-source rock with gas-prone kerogen type, relatively high TOC values and moderate thermal maturity.

2. The average amount of hydrocarbon generated from the Xiahuayuan shales is about 4.33?cm³ CH₄/g rock, indicating a potential to form a shale gas reservoir.

3. Owing to the influence of diabase intrusions, the Xiahuayuan shales have entered the dry gas window at relatively shallow-buried depths.

4. Small- and medium-sized basins have the potential to generate commercial gas reservoirs with the generated volume mainly a product of the thickness and maturity of black shales.

     

神府大柳塔2~(-2)煤层煤岩学特征

对神府大柳塔矿区 2 - 2煤层系统的煤岩学研究表明 ,该煤层以镜质体和丝质体为主 ,其它组分较少 ,矿物质中以粘土类和石英为主 ,显微煤岩类型以两组分微类型为主 ,宏观煤岩类型以半暗煤和半亮煤为主 ,壳质组具有较强的荧光 ,其荧光光谱为单峰形 ,不同的壳质组分其荧光特征不同     

松辽盆地长岭断陷沙河子组页岩有机显微组分孔隙演化规律研究

有机质孔隙是页岩储集空间的重要组成部分,具有强烈的非均质性,阻碍对页岩储层质量的正确认识和评价,其本质是受有机显微组分类型及其在生烃过程中孔隙演化的影响。本文采用场发射扫描电镜和荧光显微镜定位观察手段实现特定显微组分孔隙发育特征的表征,结合Image J图像处理技术,对不同演化阶段的显微组分进行定量化统计,总结不同有机显微组分的孔隙演化规律。研究结果表明:固体沥青孔隙度随着成熟度的升高呈现先增加后减小的趋势,在固体沥青反射率SBR_O介于1.6%～2.0%时,固体沥青孔隙最为发育,而以SBR_O=2.0%为界,固体沥青孔隙度开始减小。镜质体和惰质体的孔隙发育规律相似,随着成熟度增加,总体表现出先减小而后微弱增加的趋势。在生油窗阶段,镜质体和惰质体孔隙度最小,无机矿物和固体沥青的充填使胞腔孔隙损失达90%以上,而进入高成熟阶段,固体沥青孔隙的发育使原始胞腔孔隙得到一定程度的恢复,成为镜质体和惰质体残余孔隙的主要贡献者,贡献率达56.73%和100%,可见固体沥青孔隙对页岩储层储集空间的重要性。综合沉积成岩作用和生烃作用,页岩储层在未成熟阶段和高成熟阶段晚期孔隙最为发育,前者有机质以原始胞腔孔隙为主,后者以固体量孔隙为主。明确有机显微组分孔隙演化规律为页岩有利储层预测和页岩气生产开发储层改造提供参考。     

西北地区侏罗纪煤系烃源岩和油气地球化学特征

阿尔金断裂以北的新疆地区煤系泥岩和煤均很发育,而以南的甘青宁地区湖相和沼泽相泥岩发育。煤系烃源岩中主要的成烃显微组分是壳质体、藻类体、基质镜质体等,有机质类型以Ⅲ型为主;煤系泥岩一般为中到差油源岩,少数为好烃源岩,煤一般为差油源岩,下侏罗统源岩生烃潜力高于中侏罗统源岩;煤系原油一般为成熟的轻质、中蜡、低凝固点、低硫优质原油;油源对比表明煤系泥岩是主要烃源岩,煤和碳质泥岩是次要烃源岩;有利生油区域基本分布在侏罗纪的沉降沉积中心,而且后续埋藏又较深的山前坳陷区域。     

Organic petrology and source rock potential of sediments in the Eromanga Basin, South Australia

Cuttings and cores from the Poolowanna 1 well, Eromanga Basin, South Australia (in which oil was discovered in Lower Jurassic reservoirs) and the Macumba 1 well (no oil) have been analyzed petrographically to assess the nature of the coals and dispersed organic matter present. The Jurassic and Cretaceous coals have medium to high vitrinite contents, low to relatively high exinite, and medium to low inertinite contents. The dispersed organic matter has comparatively less vitrinite, more exinite and/or more inertinite than the associated coals. The microlithotype compositions of the coals indicate that the original vegetation was largely woody in character and was buried before much oxidation had occurred.The Jurassic sediments contain up to 2% dispersed organic matter by volume, 0–75% of which is exinite, including alginite. Vitrinite reflectances range from 0.5 to 0.7%. Where sufficiently mature, the Jurassic sediments are good potential source rocks for hydrocarbons.Statistical testing of the analytical results for the Jurassic Poolowanna Formation using Kendall's τ as a measure of dependence shows that there is a significant association between the macerals in coal and dispersed organic matter. The ratio of exinite to inertinite in dispersed organic matter is reasonably well predicted by the corresponding ratio in the associated coal.     

煤炭显微煤岩组分与工业分析关系研究

通过分析宁夏各煤田中部分具有代表性煤矿勘查阶段钻孔煤岩煤样测试数据,研究了煤的显微煤岩组分与工业分析之间的关系。随着煤中有机组分、无机组分含量的变化,煤的灰分、挥发分、固定碳发生变化。煤中有机组分含量大于90%时,煤中灰分与黏土类含量存在正相关,挥发分与惰质组和壳质组含量均存在正相关,且惰质组含量影响更大;有机组分含量小于90%时,煤中灰分与惰质组和黏土类含量均存在正相关,且惰质组含量影响更大,挥发分与壳质组含量存在正相关。煤中固定碳含量受镜质组含量影响最大,二者存在正相关。     

四川盆地五峰-龙马溪组页岩成熟度研究

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.      

淮南煤田二叠系沉积相特征及其与烃源岩的关系

在对淮南地区二叠系岩性、矿物和生物化石进行观测研究以及相关地球化学参数测试的基础上,对淮南地区这一时期的沉积相演化特征及其与烃源岩之间关系进行分析。结果表明:淮南地区早、中二叠世时期海水震荡性后退,总体以水下沉积为主,大致可划分为2种沉积亚相:山西组的三角洲沉积和下石盒子组的水下分流河道沉积,又可以进一步细分为前三角洲、泥炭沼泽、分流河道、决口扇、河漫滩等微相,泥页岩在前三角洲和河漫滩相最发育。岩性和显微组分的组成受沉积微环境变化的控制作用明显,“（腐泥组+壳质组）/∑显微组分”以大于等于70%为主,利于生气;有机碳含量则受沉积亚相和沉积微环境的共同控制,山西组泥页岩中有机碳平均质量分数约2.78%,明显高于下石盒子组泥页岩中的1.11%。综合考虑泥页岩累计厚度、有机碳含量及有机质的显微组成等因素认为,研究区山西组和下石盒子组都可作为页岩气的有利勘探层位,尤以“潘集镇-潘集区-泥河镇-平圩镇”这一带最为有利。