新疆中生代煤中半镜质组特征及其研究意义

通过分析显微图像的光学性质和测定煤的反射率等方法,研究了新疆中生代煤中半镜质组特征。结果表明:新疆中生代煤中含有一定量的半镜质组;均质半镜质体占总体(均质镜质体与均质半镜质体之和)的49%~64%,均质半镜质体的最大反射率(R_max)比均质镜质体的高0.08%~0.13%;均质半镜质体的R_max介于均质镜质体和结构镜质体之间,结构半镜质体的R_max比结构镜质体的高0.28%~0.34%。由此可以得出:在三大组分划分方案中,应将均质半镜质体归入镜质组的均质体中,同时认为,按显微组分三大组分划分方案中,将结构半镜质体归入惰质组的半丝质体中更合理;在测定煤的反射率时,不能将均质半镜质体作为反射率的测定对象。本项研究结果对于指导本地区煤炭的炼焦配煤、煤炭液化和深加工利用等具有重要意义。      

吐哈盆地侏罗系煤中超微类脂体特征和演化

利用共聚焦激光显微镜和透射电镜对吐哈盆地侏罗系煤进行超微层次有机岩石学分析，发现微米级以下超微类脂体普遍存在于无结构镜质体和一些粗粒体之中。常规光学显微镜下难以分辨超微类脂体，在镜质体反射率Ｒｏ０．５０％￣０．７０％时，煤中超微类脂体数量一般为８％￣１２％。超微类脂体的光性演化明显领先于壳质组形态组分孢子体和角质体，它是吐哈侏罗系煤中重要的生油组分。     

木栓质的菌解-热模拟实验特征及木栓质体的成烃演化机制

木栓质体是我国南方树皮煤的主要显微组分,在西北地区侏罗系煤层中也具有相当高的含量,是一种早期生油的显微组分,对煤成油和未熟-低熟油气的形成具有重要贡献。本文通过对被子植物栓皮栎周皮木栓组织的细菌降解和加水热模拟实验研究,系统地探讨了显微组分木栓质体的生物先质-木栓质的成烃演化过程,结果表明：木栓质可以被细菌降解,并具有两次热解油气生成高峰,分别相当于镜质体反射率0.35%～0.5%和0.8%～1.1%左右。角质体和树皮体的自然演化系列和热模拟实验结果也具有相似的特点。我们认为：(1)木栓质体的生烃潜力并没有在传统的“油窗”之前就消耗殆尽,在较高演化阶段仍然具有一定的油气生成潜力;(2) 木栓质体的热演化特征可以由木栓质的类脂特性来解释,现代植物木栓组织的化学结构特征和宏观大分子热稳定性的差异是显微组分木栓质体热降解多阶段生烃的主要原因;(3)木栓质热演化早期生成的液态油以含氧的胶质化合物为主,晚期则生成大量的C12+的高蜡油。     

可作为有机相指标的镜质体反射率

近期许多学者报道了镜质体反射率发生异常变化的现象.本文在笔者研究的基础上,综合国内外最新研究成果,提出了镜质体反射率的原生和次生变化的概念,详细论述了影响镜质体反射率的因素,重点讨论了镜质体反射率与有机质的类型丰度的关系,在此基础上提出镜质体反射率可作为确定有机相的指标.     

煤显微组分中有机硫的微区分析和分布特征

应用扫描电镜、能谱仪和波谱仪测定了煤中有机硫含量。a.在镜质体有机硫含量低于0.50％的煤中,惰质体的有机硫含量与其相近。而在镜质体有机硫含量高于0.5％的煤中,惰质体的有机硫含量大多为镜质体的40％～50％。各种镜质体和惰质体的有机硫含量随其凝胶化程度增高而增加。b.聚煤古地理环境对煤中有机硫含量起决定性作用。以镜质体为例,形成于湖滨三角洲平原环境的神木煤含有机硫0.21％,形成于滨海三角洲平原环境的水城大河边煤含有机硫0.84％,形成于泻湖海湾环境的兖州晚石炭世煤含有机硫2.24％。     

吐哈盆地煤成烃主要贡献组分剖析

吐哈盆地中下侏罗统煤显微组分组成显示了“碎、小、薄”和过渡组分含量高的特点。结合显微和超微层次有机岩石学分析，在显微组分层次生烃组分主要为基质镜质体，碎屑类脂体、薄壁角质体、木栓质体和小孢子体在煤成烃中也有一定的贡献；超微层次生烃组分主要表现为分布于基质镜质体中的超微类脂体。煤中基质镜质体的高含量弥补了其单位生烃潜力低的不足，基质镜质体富氢成因在于生物化学阶段细菌等微生物对其强烈降解改造作用。     

不同类型镜质体荧光特征差异性及原因

对我国不同时代和地区125块煤样中镜质体荧光性进行了详细的荧光光度术分析，表明镜质组的荧光性不仅取决于煤阶，而且也与镜质体类型紧密相关。不同类型镜质体显示了不同的荧光强度，在石油窗阶段，富氢镜质体荧光强度明显高于正常镜质体，差值可达1-3倍，特别是富氢镜质体在0.5%-0.85% Rｏ阶段荧光强度一直较强，且荧光强度值的变化与煤阶没有较好的相关性，显示了明显的特殊性。镜质组相对荧光强度与超微类脂体含量、可溶有机质数量呈正相关关系。富氢镜质体较强的荧光性和Ｒｏ在0.50%-0.90%之间荧光强度特殊的演化规律与其中含有较丰富的超微类脂体以及富氢镜质体中流动相含量较高二方面因素有关。     

栓皮栎的热模拟特征及木栓质的成烃演化

由于大多数沉积有机质或煤层中的木栓质体在很低演化阶段荧光就消失了，使得地球化学家和煤岩学家往往低估了木栓质体对成烃的贡献。利用显微镜荧光检测和显微傅里叶红外光谱技术对现代植物栓皮栎的树皮进行人工热模拟研究，结果表明现代木栓组织和木检质成分是一种高度偏油的有机质，在低热力条件下释放出大量的以异构烃和环烷烃为主的液态烃类，大约在镜质体反射率为０．５％之前，生成Ｃ６＋烃类总量的２／３以上。现代木栓热模拟生烃现象要滞后于地质体中的木栓质体，它不能完全复制木栓质体的自然熟化过程     

煤的液化性能与煤质关系研究进展

煤的液化潜力与煤岩成分和煤化作用程度有着密切的关系,更进一步研究煤岩成分中不同显微组分对液化的影响,探讨显微组分的结构,将对优质液化煤的讦价起重大作用。煤中不同的显微组分具有不同的光性特征,镜质体反射率是划分煤阶的主要参数,但是煤的全显微组分反射率的研究把煤岩成分与煤阶结合起来,对液化煤进行综合评价。本文介绍了国外这方面最近的一些研究成果:1．镜质组和壳质组具有非常类似的转化率,但是抽提产物中族组分却存在显著的差异,镜质组主要出现前沥青烯和沥青烯,而壳质组主要出现油和气。2．低反射率惰性组显微组分虽然转化率较低,但是主要产出油和气。3．相对未凝胶化的显微组分具有较高的油产率,而较高凝胶化程度的显微组分油产率却较低。4．煤的全显微组分反射率分布可以预测煤的液化潜力。     

原油中镜质体碎屑的检出及其地质意义

应用共聚焦激光扫描显微镜观察和分析了准噶尔盆地侏罗系原油，在国内首次发现这些原油中存在镜质体碎屑。这些镜质体碎屑均具有明显的棱角，其反射率值和侏罗纪煤的反射率值相近，且产出镜质体碎屑的原油均普遍检出了具有高等植物为母质输入的生物标志化合物。因此原油中镜质体碎届的检出为确认准噶尔盆地煤成油的存在提供了可靠的依据。     

Geological and laboratory evidence for early generation of large amounts of liquid hydrocarbons from suberinite and subereous components

Suberinite, and subereous components of amorphous nature, comprise largely unrecognized, proficient sources of liquid hydrocarbons. Due to difficulties in recognizing the presence of subereous components and suberinite in organic sediments, the contributions of these liptinitic components to the organic input of source rocks are easily underestimated. Severe chemical alterations of suberinite in the vitrinite reflectance range of R_o = 0.35–0.60% are demonstrated. Organic geochemical data, obtained from samples subjected to natural maturation, reveal that subereous components/suberinite undergoes early thermal degradation to generate large amounts of hydrocarbons below R_o = 0.60%. Data obtained from laboratory maturation of immature, suberinite-rich coals indicate that about 50% of the potential of suberinite for generating C₁₂₊ hydrocarbons has already been exhausted during natural maturation of the samples, prior to the onset of the traditionally defined “oil window”. The present data (a) contradict the assumption that suberinite is mainly sourced by selective preservation/enrichment of a stable, highly aliphatic biopolymer, i.e. “suberan” and (b) suggest that suberinite contains appreciable amounts of aliphatic and aromatic moieties which are released at low thermal stress.     

The optical features and hydrocarbon-generating model of “barkinite” from Late Permian coals in South China

Leping coal is known for its high content of “barkinite”, which is a unique liptinite maceral apparently found only in the Late Permian coals of South China. “Barkinite” has previously identified as suberinite, but on the basis of further investigations, most coal petrologists conclude that “barkinite” is not suberinite, but a distinct maceral. The term “barkinite” was introduced by (State Bureau of Technical Supervision of the People's Republic of China, 1991, GB 12937-91 (in Chinese)), but it has not been recognized by ICCP and has not been accepted internationally.In this paper, elemental analyses (EA), pyrolysis-gas chromatography, Rock-Eval pyrolysis and optical techniques were used to study the optical features and the hydrocarbon-generating model of “barkinite”. The results show that “barkinite” with imbricate structure usually occurs in single or multiple layers or in a circular form, and no definite border exists between the cell walls and fillings, but there exist clear aperture among the cells.“Barkinite” is characterized by fluorescing in relatively high rank coals. At low maturity of 0.60–0.80%R_o, “barkinite” shows strong bright orange–yellow fluorescence, and the fluorescent colors of different cells are inhomogeneous in one sample. As vitrinite reflectance increases up to 0.90%R_o, “barkinite” also displays strong yellow or yellow–brown fluorescence; and most of “barkinite” lose fluorescence at the maturity of 1.20–1.30%R_o. However, most of suberinite types lose fluorescence at a vitrinite reflectance of 0.50% Ro, or at the stage of high volatile C bituminous coal. In particular, the cell walls of “barkinite” usually show red color, whereas the cell fillings show yellow color under transmitted light. This character is contrary to suberinite.“Barkinite” is also characterized by late generation of large amounts of liquid oil, which is different from the early generation of large amounts of liquid hydrocarbon. In addition, “barkinite” with high hydrocarbon generation potential, high elemental hydrogen, and low carbon content. The pyrolysis products of “barkinite” are dominated by aliphatic compounds, followed by low molecular-weight aromatic compounds (benzene, toluene, xylene and naphthalene), and a few isoprenoids. The pyrolysis hydrocarbons of “barkinite” are mostly composed of light oil (C₆–C₁₄) and wet gas (C₂–C₅), and that heavy oil (C₁₅⁺) and methane (C₁) are the minor hydrocarbon.In addition, suberinite is defined only as suberinized cell walls—it does not include the cell fillings, and the cell lumens were empty or filled by corpocollinites, which do not show any fluorescence. Whereas, “barkinite” not only includes the cell walls, but also includes the cell fillings, and the cell fillings show bright yellow fluorescence.Since the optical features and the hydrocarbon-generating model of “barkinite” are quite different from suberinite. We suggest that “barkinite” is a new type of maceral.     

Evidence of early generation of liquid hydrocarbon from suberinite as visible under the microscope

The early generation of liquid hydrocarbons from suberinite can be clearly observed under the microscope. The generation of this oil-like material, mainly in the form of exsudatinite, from the maceral suberinite occurs at a maturity level of about 0.4% vitrinite reflectance. Hydrocarbons appear to be naturally expelled from coal initially through sweating and agglomeration of suberinite which subsequently forms exsudatinite. It is suggested that extensive expulsion of exsudatinite causes cracks to develop in vitrinite whereas limited expulsion of exsudatinite will only impregnate the vitrinite matrix. If cracks are formed, it is possible they could progressively develop to form an exsudatinite-crack network. The formation of such a network is believed to represent an effective way of hydrocarbon expulsion from coal source rocks.     

Observations on Indian Permian Gondwana Coals Under Fluorescence Microscopy: An Overview

Macerals like sporinite, cutinite, suberinite and resinite of the liptinite group have been insufficiently recorded in Indian Permian Gondwana coals, until the fluorescence microscopy came into existence. With the introduction of this technique, macerals like bituminite, fluorinite and exsudatinite were convincingly recognized and alginite and liptodetrinite, normally mistaken for mineral matter under normal reflected light in routine coal petrographic analysis, were identified with certainty. Thus, fluorescence microscopy has added certain new macerals to the tally of the liptinite group and has increased their overall proportion in Indian Gondwana coals.In addition to the liptinite group, collodetrinite (=desmocollinite) and a certain fraction of collotelinite (=telocollinite) macerals of the vitrinite group were found to be fluorescing with dull reddish-brown to dark brown colours. Certain semifusinite and inertodetrinite macerals of inertinite group were also found to fluoresce with almost identical intensity and colour as that of the associated perhydrous (fluorescing) vitrinite. Contributions of degraded resinite, algal matter and bitumen in the formation of perhydrous vitrinite have been established. The fluorescence behaviour of inertinite appears to be related with its genesis from partial oxidation of resin/bitumen-impregnated cell walls.     

Artificial bacterial degradation and hydrous pyrolysis of suberin: Implications for hydrocarbon generation of suberinite

The organic maceral suberinite is widely believed to be a contributor to immature or low mature oils with R_o < 0.5% in some coal and terrigenous sequences. However, its evolution of hydrocarbon generation, especially in the relatively high maturation stage of R_o > 0.5%, has not been sufficiently characterized. This issue was addressed herein using periderm cork tissues of the modern angiosperm Quercus suber (suberin), which is a possible bio-precursor of suberinite, in artificial bacterial degradation and hydrous pyrolysis experiments. Integrated studies were conducted, including analyses on the compositions of hydrocarbon yields and the content variations that were generated during the experiments, gas chromatography (GC) analyses of generated oils and spectral fluorescence observations, and Rock-Eval and Fourier Transform Infrared (FTIR) microspectroscopic studies on solid residues. Analytical results indicate that suberin and suberinite have long and complex hydrocarbon generation histories. In general, the hydrocarbon that is generated during bacterial degradation is predominantly gas and present in relatively limited amounts, while the oils mainly are generated during hydrous pyrolysis. Furthermore, the oil generation has two peaks that correspond to R_o of approximately 0.35–0.50% and 0.80–1.10%. In composition, the early generated oil mainly consists of long chain waxy and oxygen containing compounds, while the late generated oil is relatively enriched in aromatic compounds. These features can be ascribed to the chemical nature (e.g., composition and structure) of suberin. It is a type of insoluble and high molecular weight polyester compound that contains large quantities of long chain structure dicarboxylic acids and alcohols. Consequently, the deoxygenization of these compounds can take place under relatively low thermodynamic conditions, generating liquid oil that is dominated by a long chain structure and oxygen-containing waxy compounds. In contrast, the degradation of the phenolic compounds results in the second oil generation peak. Therefore, suberinite has a two stage and relatively long oil generation history and is a good bio-precursor for coal-derived oil generation.     

A combined pyrolysis mass spectrometric and light microscopic study of peatified Calluna wood isolated from raised bog peat deposits

Stem wood of the Angiosperm Calluna vulgaris (Scotch heather), isolated at different depths from a selection of raised bog peat deposits, was chemically characterized using in-source pyrolysis mass spectrometry (Py-MS) and Curie-point pyrolysis gas chromatography mass spectrometry (Py-GC-MS). Light microscopy was performed to relate mass spectrometric characteristics with anatomical features. Peatified wood samples, isolated from increasing depth show a gradual decrease in carbohydrate content. This decrease in anatomically reflected in a selective removal of secondary cell wall material from the fibre-tracheids and wood parenchyma. During prolonged peatification a selective removal of hemicellulose sugars is observed, while a part of the cellulose fraction is preserved. This highly resistant cellulose is mainly located in the secondary cell walls of the vessels. The lignin macromolecule is preserved, but a gradual decrease in syringyl to guaiacyl ratio (S/G) is observed during peatification. Because no increase in catechol and phenolic compounds is observed, we conclude that S/G shifts are due to removal the of syringyl-rich secondary cell wall material and the retention of guaiacyl-rich compound middle lamella. Small chemical changes in the lignin macromolecule involve shifts in oxygen substitutions on the aliphatic side chains of the methoxyphenolics and the occurrence of aromatic acids.     

Assessment to the potential mobility and toxicity of metals and metalloids in soils contaminated by old Sb–Au and As–Au mines (NW Portugal)

The main purpose of this study is to assess arsenic and antimony availability in soils, as well as Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn availability in soils derived from the schist–metagraywacke complex close to old Sb–Au mines and in soils developed from Ordovician slates and close to an old As–Au mine in Portugal. The availability was determined using a European certified sequential extraction procedure (BCR). The results demonstrated that metalloids are not readily bioavailable, because they are mainly associated with the residual fraction. Arsenic and antimony proportions in exchangeable fractions are up to 3 and 1%, respectively. However, arsenic is up to 24% in oxy-hydroxide fractions, while antimony is up to 4% in them, demonstrating the highest bioavailability of arsenic compared to that of antimony, as metalloids are weakly bound to the soils in that fraction. Therefore, arsenic tends to be more toxic than antimony in all soils studied. However, the pseudo-total contents show that both metalloids are above the Italian and Dutch guidelines. Therefore, if physico-chemical changes occur arsenic and antimony will show higher potential environmental risk than evidenced by Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn.     

Dislocation structure of the deformation lamellae in synthetic quartz; a study by electron and optical microscopy

Single crystals of experimentally deformed synthetic quartz showing optical deformation lamellae were examined by transmission electron microscopy. Dislocations are distributed fairly uniformly throughout the crystal. However, parallel to the trace of the deformation lamellae, which may be irrational, there are walls of tangled dislocations whose characteristics suggest that they are directly associated with the lamellae. The nature and formation of the optical image is discussed in detail.     

吐哈盆地西部地区高蜡凝析油和轻质油的地球化学特征及成因分析

吐哈盆地西部地区中、新生界储层中广泛分布着轻质油和凝析油。这些原油具有低密度、低粘度、中等—高含蜡量的特点 ,含蜡量为 5 .5 %～ 2 2 .1% ,高分子量正构烷烃 (n C35～ n C87)含量较高 ,属中—高蜡轻质油或凝析油 ,其地球化学特征及成因机理既不同于常规的高蜡原油 ,又不同于一般意义上的凝析油。吐哈盆地中、新生界高蜡凝析油或轻质油主要来源于侏罗系湖相泥岩和煤系地层中泥岩或煤 ,其形成主要取决于烃源岩的有机显微组分和有机质演化程度。研究区侏罗系湖相泥岩和煤系地层泥岩或煤岩中有机显微组分均以镜质组和壳质组为主 ,壳质组中角质体和木栓质体含量较高 ,具备了既可形成凝析油 ,又可形成高蜡油的条件。由于镜质组与部分壳质组演化形成烃类化合物的活化能相当 ,因此又具备高蜡油与凝析油共生的地球化学条件