煤镜质组反射率的定向特征及其应力指示意义 ——以淮北矿区为例

基于淮北矿区4个矿井共15块煤定向样品的镜质组反射率测试数据,在相容性调整的基础上,开展煤样镜质组反射率三维椭球体进行拟合。结合区域及采样地成煤后构造演化分析及煤样变形类型特征,深入研究煤镜质组反射率三维椭球体的方位和形状对应力、温度和变形结构的响应,并探讨其内在机理。结果显示:煤镜质组反射率三维椭球体最大—中间反射率所在平面的倾向多与区域应力来源方向相近,其原因可能归结于煤中芳香片层向垂直于岩石圈当中近水平构造应力和上覆地层压力的合力方向优势发育。垂直于挤压应力方向延伸的断层的干扰、煤变形程度和多期应力场的叠加效应是导致少数样品指示异常的主因。在多期应力场叠加影响区域,镜质组反射率定向会向后期应力方向发生不同程度偏转。但对于强变形构造煤,煤体颗粒间的移位旋转会削弱镜质组反射率重新定向偏转的程度,使其镜质组最大—中间反射率平面倾向主要指示前期应力来源方向。岩浆热异常是导致最大—中间反射率所在平面陡倾的主要因素之一。根据弗林参数,多数样品表现为扁椭球型,仅是煤正常演化的反映,而长椭球型则主要反映了岩浆热异常的的影响。     

安徽淮北煤田推覆构造中煤镜质组反射率各向异性研究

安徽省淮北煤田推覆构造外来系统与原地系统中的煤镜质组反射率各向异性特征存在明显差异,反映不同的应力应变状态。外来系统中最小反射率的倾向由北北西转至北西西,代表推覆体前锋带的应力状态;反射率光率体以长球形椭球体为主,意味着推覆过程中伴随有侧向伸长变形。原地系统中最小反射率的倾向为南南西和南南东,保存了区域性南北向挤压的痕迹;反射率椭球体有限应变分析结果为压扁型应变。本文的实例表明,煤镜质组反射率各向异性分析技术是研究煤田推覆构造的一种可行手段。     

实验变形煤结构的13C NMR特征及其构造地质意义

通过４件煤的高温高压实验样品及２件原始样品的＾１３Ｃ固体核磁共振研究,揭示了变形煤结构演化的微观机理及其与镜质组反射率光性变异的内在联系,阐明了不同应变环境中应力作用的差别在一定程度上控制了碳结构的演化,而镜质组反射率的差别正是煤结构差异的外在反映,因此,煤镜质组反射率光性组构真实地记录了煤变形历史中应力作用及应变环境特征,是煤田构造研究中极为重要的应变标志之一。     

大别山北麓高煤级煤的变形——变质类型

对中国东部大别造山带前陆盆地石炭纪含煤岩系的高煤级煤进行了深入研究,划分出3种变形——变质类型。构造——热变质类型煤样采自剪切应变带内,煤镜质组反射率各向异性显著,煤结构参数L_c最大,L_a/L_c和d₀₀₂最小,TEM下存在局部石墨化现象,呈现动力变质特征。岩浆热变质类型煤样受中生代花岗岩侵入体异常高温影响,Ro_max和Ro_bi较大,显微镜下呈非均质结构,L_a/L_c在3类煤中最大。区域变质类型煤的Ro_max最小,但仍远远高于稳定地区相近地质时代煤,反映了造山带旁侧构造——热活动背景下有机质的高演化程度。     

煤镜质组反射率光性组构变形实验研究

不同煤级煤的高温高压实验表明，在温、压和差异应力作用下，煤镜质组反射率值和各向异性都有一定程度增加，变形越强烈，增加越明显，尤其在中煤级中、晚期阶段更是如此。在变形过程中，反射率主轴将发生有规律的偏转，变形越强烈，最小反射率主轴越接近于最大挤压应力方向。随着变形的增强，镜质组反射率椭球由单向伸长同压缩型转化。     

构造煤化学结构演化与瓦斯特性耦合机理

煤是对应力和应变非常敏感的一种特殊岩石,在不同的应力-应变环境和构造应力作用下,煤的物理结构、化学结构及其光性特征等都将发生显著变化,从而形成具有不同结构特征的、不同类型的构造煤。构造煤在变形的过程中,镜质组反射率将发生规律性变化,并被较为广泛地应用于煤田构造的定量研究,高温高压变形实验也证实了这一现象。为了深入探讨煤镜质组光性组构变化的微观机理,将X-射线衍射、顺磁共振和核磁共振等技术应用于不同类型构造煤以及高温高压实验变形煤的化学结构研究。研究表明,构造煤化学结构演化与镜质组反射率的演化具有密切的内在联系,镜质组反射率的光性异常是构造煤化学结构演化在物理光学性质上的具体体现。不同类型的构造煤由于物理和化学结构上的不同,导致瓦斯含量和透气性等瓦斯特性上的重大差异,糜棱煤特殊的物理和化学结构决定了其高含气量和低透气性的特征,是矿井瓦斯突出的危险地带,因此,可以通过构造煤分布规律的研究,进行矿井瓦斯富集与突出危险性的评价与预测,为矿井瓦斯灾害的研究提供新的思路和方法。     

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。      

煤镜质组反射率各向异性特征在构造应力场分析中的应用

煤镜质组反射率各向异性分析,是研究煤田构造应力场的一种有效方法。本文阐述了镜质组反射率各向异性的成因、取样、测量以及资料的处理方法。通过洪山殿煤矿区的镜质组反射率各向异性分析,得出了本区存在多期构造应力场叠加的结论。     

变形煤镜质组反射率演化的地化机理及其地质意义

通过X射线衍射(XRD)、电子顺磁共振(EPR)和核磁共振(NMR)等方法深入探讨了高温高压实验和构造煤样的化学结构演化特征,阐明了变形煤镜质组反射率的变化是其微观化学结构演化的外在反映。变形煤镜质组反射率的演化又受到应力和变形环境等因素的深刻影响,其真实地记录了构造变形历史中应力作用和应变环境等特征,是进行煤田构造研究的重要标志物之一      

变形煤镜质组反射率演化的地化机理及其地质意义

通过X射线衍射(XRD)、电子顺磁共振(EPR)和核磁共振(NMR)等方法深入探讨了高温高压实验和构造煤样的化学结构演化特征,阐明了变形煤镜质组反射率的变化是其微观化学结构演化的外在反映。变形煤镜质组反射率的演化又受到应力和变形环境等因素的深刻影响,其真实地记录了构造变形历史中应力作用和应变环境等特征,是进行煤田构造研究的重要标志物之一。     

Analysis of relationships between geochemical parameters of petroleum potential in related source and carbonaceous materials

A worldwide data set of 1,085 samples containing organic matter of the type II/III kerogen from Carboniferous to Cenozoic was used to analyse the evolution of the hydrogen index (HI), quality index (QI), and bitumen index (BI) with increasing thermal maturity. The HI_max, QI_max and BI_max lines were defined, based on statistical analysis and cross-plots of HI, QI and BI versus the vitrinite reflectance (%Ro) and T _max (°C). The constructed HI, QI and BI bands were broad at low maturities and gradually narrowed with increasing thermal maturity. The petroleum generation potential is completely exhausted at a vitrinite reflectance of 2.0–2.2 % and T _max of 510–520 °C. An increase in HI and QI suggests extra petroleum potential related to changes in the structure of the organic material. A decline in BI signifies the start of the oil window and occurs within the vitrinite reflectance range 0.75–1.05 % and T _max of 440–455 °C. Furthermore, petroleum potential can be divided into four different parts based on the cross-plot of HI versus %Ro. The area with the highest petroleum potential is located in “Samples and methods” with %Ro = 0.6–1.0 %, and HI > 100. Oil generation potential is rapidly exhausted at “Results and discussion” with %Ro > 1.0 %. This result is in accordance with the regression curve of HI and QI with %Ro based on 80 samples with %Ro = 1.02–3.43 %. The exponential equation of regression can thus be achieved: HI = 994.81e^?1.69Ro and QI = 1,646.2e^?2.003Ro (R ² = 0.72). The worldwide organic material data set defines two range of oil window represented by the upper and lower limits of the BI band: %Ro 0.75–1.95 %, T _max 440–525 °C, and %Ro 1.05–1.25 %, T _max 455–465 °C, respectively.     

豫北煤田焦作、鹤壁、安阳矿区二1煤层优势断裂构造地球化学特征

对豫北煤田焦作、鹤壁和安阳矿区二１煤层的对比样（构造煤和原生结构煤）进行了显微镜和扫描电镜下观察、镜质组反射率测试、Ｘ射线衍射分析和化学分析等。研究结果表明,构造煤因发生了断裂构造地球化学作用,其化学成分、元素成分和煤分子结构与原生结构煤明显不同：构造煤的挥发分含量（％）比原生结构煤一般要小０．５５～３．４８,平均要小１．５９;构造煤和原生结构煤相比,碳含量（％）平均增加了３．１,氢含量（％）平均     

川北阿坝地区三叠系粘土矿物特征及地质意义

分析了川北阿坝地区三叠系泥质岩的岩石矿物组合、粘土矿物类型、伊利石结晶度和镜质体反射率特征,并以此划分成岩演化阶段及变质程度。以成岩作用—极低级变质作用的研究方法,明确了阿坝地区成岩作用及极低级变质作用的上、下界限及区域分布规律:以唐克为中心的地区处于成岩作用晚期阶段,成岩作用温度200～212℃,伊利石结晶度IC≥0.42;周围地区处于极低级变质作用阶段,成岩作用温度212～222℃,伊利石结晶度IC<0.42。镜质体反射率(Ro)也具有同样的演化规律。对该地区域上成岩演化的差异及原因作如下解释:由于构造活动的远近程效应存在差异,该地区的周缘明显受到构造作用的影响,因叠加动力变质而达到极低级变质作用阶段;唐克位于阿坝地块中心,受构造作用的影响相对较小,因而处于成岩作用晚期阶段。     

Evaluation of coal bed methane potential of coal seams of Sawang Colliery,Jharkhand, India

The coal seams of Sawang Colliery, East Bokaro Coalfields are bituminous to sub-bituminous in nature and categorized as high gaseous seams (degree II to degree III level). These seams have the potential for coal bed methane (CBM) and their maturity increases with increasing depth, as a result of enhanced pressure-temperature conditions in the underground. The vitrinite maceral group composition of the investigated coal seams ranges from 62.50–83.15%, whereas the inertinite content varies from 14.93–36.81%. The liptinite content varies from 0.66% to 3.09%. The maximum micro-pores are confined within the vitrinite group of macerals. The coal seams exhibit vitrinite reflectance values (Ro% calculated) from 0.94% (sample CG-97) to 1.21% (sample CG-119). Proximate analyses of the investigated coal samples reveal that the moisture content (M%) ranges from 1.28% to 2.98%, whereas, volatile matter (VM%) content is placed in the range of 27.01% to 33.86%. The ash content (A%) ranges from 10.92% to 30.01%. Fixed carbon (FC%) content varies from 41.53% to 55.93%. Fuel ratio variation shows a restricted range from 1.53 to 1.97. All the coal samples were found to be strongly caking and forming coke buttons. The present study is based on the adsorption isotherm experiments carried out under controlled P-T conditions for determination of actual gas adsorption capacity of the coal seams. This analysis shows that the maximum methane gas adsorbed in the coal sample CG-81 is 17 m³/t (Std. daf), at maximum pressure of 5.92 MPa and experimental temperature of 30°C. The calculated Langmuir regression parameters P_L and V_L range from 2.49 to 3.75 MPa and 22.94 to 26.88 m³/t (Std. daf), respectively.     

Changes in hydrocarbon maturity indices with coal rank and type,Buller Coalfield,New Zealand

The Buller Coalfield (South Island, New Zealand) is an inverted late Paleogene Basin that contains middle Eocene bituminous coals which exhibit considerable variation in both coal rank (across-basin), and coal type (in-seam). Twenty-two fractionated bitumen extracts of Brunner Coal Measures coal samples from 12 drillholes were analyzed by GC and GC–MS to characterize the effect of coal rank and type on conventional hydrocarbon maturity indices at the beginning and end of the oil window (0.56–1.26% Ro_max).The Carbon Preference Index, pristane/phytane and isoprenoid/n-alkane ratios evolve throughout the high volatile bituminous B rank stage, while other biomarker ratios [18α(H)-22,29,30-trisnorneohopane/17α(H)-22,29,30-trisnorhopane (Ts/Tm), 18α(H),21β(H)-30-norneohopane (C₂₉ Ts)/17α(H),21β(H)-30-norhopane and C₃₀ diahopane/hopane] do not show appreciable change in value until medium volatile bituminous rank. Various aromatic based ratios appear to be more effective in delineating rank throughout the entire oil window; in particular the Methylphenanthrene Index and vitrinite reflectance are positively correlated over the entire bituminous rank range. However, subtle changes in depositional conditions (variable coal type) complicate these rank estimates. Within a given coal seam, variation in CPI, isoprenoid/n-alkane and hopane/sterane ratios appear to be related to the hydrogen content of the coal, while the homohopane index and the oleanane/hopane ratio covary with sulfur content. As with depressed vitrinite reflectance values, MPI is similarly lowered in the perhydrous samples. The mechanisms that control these hydrocarbon parameters during deposition and diagenesis are complex and convoluted, however, changes in bacterial activity and community (with marine incursion) appear to play an important role. Due to these anomalies, none of the hydrocarbon maturity indices calculated can be singularly used to constrain coal rank.     

Evolution of optical properties of vitrinite, sporinite and semifusinite in response to heating under inert conditions

The objective of the study was to characterize changes of reflectance, reflectance anisotropy and reflectance indicating surface (RIS) shape of vitrinite, sporinite and semifusinite subjected to thermal treatment under inert conditions. Examination was performed on vitrinite, liptinite and inertinite concentrates prepared from channel samples of steam coal (R_r = 0.70%) and coking coal (R_r = 1.25%), collected from seam 405 of the Upper Silesian Coal Basin. The concentrates were heated at temperatures of 400–1200 °C for 1 h time in an argon atmosphere.All components examined in this study: vitrinite, sporinite and semifusinite as well as matrix of vitrinite and liptinite cokes, despite of rank of their parent coal, show, in general, the most important changes of reflectance value and optical anisotropy when heated at 500 °C, 800 °C (with the exception of bireflectance value of sporinite) and 1200 °C.After heating the steam coal at 1200 °C, the vitrinite and the semifusinite reveal similar reflectances, whereas the latter a slightly stronger anisotropy. Sporinite and matrix of liptinite coke have lower reflectances but anisotropy (R_bi and R_am values) similar to those observed for vitrinite and semifusinite. However, at 1000 °C sporinite and matrix of liptinite coke have the highest reflectivity of the studied components. The RIS at 1200 °C is the same for all components.The optical properties of the three macerals in the coking coal become similar after heating at 1000 °C. Coke obtained at 1200 °C did not contain distinguishable vitrinite grains. At 1200 °C semifusinite and vitrinite coke matrix have highest R_r values among the examined components. Maximum reflectance (R_max) reach similar values for vitrinite and sporinite, slightly lower for semifusinite. Matrix of liptinite coke and matrix of vitrinite coke have considerably stronger anisotropy (R_bi and R_am values) than other components. RIS at 1200 °C is also similar for all components.     

Thermal alteration of coal in the Khasyn coalfield, Magadan region, Russia

The Early Cretaceous coal deposits of the Khasyn coalfield are intruded by Palaeogene diabase dikes. The coal has vitrinite reflectance values of 2.0–2.5% R_o, and characteristics of normal anthracite at some distance from the dikes, but at direct contact with the dike two morphological coal varieties occur: coal inclusions in the diabase dike and dispersed carbonaceous matter within the dike rock. Both types of coaly matter have properties typical of anthracites: strong anisotropy, altered internal structure and high vitrinite reflectance values ranging from 3.8 to 5.5% R_o. The X-ray diffraction measurements of the interplanar spacing d(002) and the crystallite sizes Lc and La show rather similar values for coal inclusions in the dike and dispersed carbonaceous matter. The additional reflection at 3.37 Å, corresponding to semi-graphite admixture, occurs in the coal and carbonaceous matter inside the dike and is absent in the natural coal outside the dike.     

Adsorption Mechanism and Kinetic Characterization of Bituminous Coal under High Temperatures and Pressures in the Linxing‐Shenfu Area

The majority of coalbed methane(CBM) in coal reservoirs is in adsorption states in coal matrix pores. To reveal the adsorption behavior of bituminous coal under high-temperature and high-pressure conditions and to discuss the microscopic control mechanism affecting the adsorption characteristics, isothermal adsorption experiments under hightemperature and high-pressure conditions, low-temperature liquid nitrogen adsorption-desorption experiments and CO2 adsorption experiments were performed on coal samples. Results show that the adsorption capacity of coal is comprehensively controlled by the maximum vitrinite reflectance(Ro, max), as well as temperature and pressure conditions. As the vitrinite reflectance increases, the adsorption capacity of coal increases. At low pressures, the pressure has a significant effect on the positive effect of adsorption, but the effect of temperature is relatively weak. As the pressure increases, the effect of temperature on the negative effect of adsorption gradually becomes apparent, and the influence of pressure gradually decreases. Considering pore volumes of pores with diameters of 1.7-100 nm, the peak volume of pores with diameters 10-100 nm is higher than that from pores with diameters 1.7-10 nm, especially for pores with diameters of 40-60 nm, indicating that pores with diameters of 10-100 nm are the main contributors to the pore volume. The pore specific surface area shows multiple peaks, and the peak value appears for pore diameters of 2-3 nm, indicating that this pore diameter is the main contributor to the specific surface area. For pore diameters of 0.489-1.083 nm, the pore size distribution is bimodal, with peak values at 0.56-0.62 nm and 0.82-0.88 nm. The adsorption capability of the coal reservoir depends on the development degree of the supermicroporous specific surface area, because the supermicroporous pores are the main contributors to the specific pore area. Additionally, the adsorption space increases as the adsorption equilibrium pressure increases. Under the same pressure, as the maximum vitrinite reflectance increases, the adsorption space increases. In addition, the cumulative reduction in the surface free energy increases as the maximum vitrinite reflectance increases. Furthermore, as the pressure increases, the surface free energy of each pressure point gradually decreases, indicating that as the pressure increases, it is increasingly difficult to adsorb methane molecules.     

一种页岩含气性热演化规律研究的模拟实验方法

目前针对页岩气赋存规律研究的热模拟实验主要是沿袭常规油气热模拟方法,以粉末态样品开展模拟,研究对象为岩石生成并排出的烃类气体,这种模拟方式未明确页岩气的实质为"滞留气",并且模拟后样品无法开展扫描电镜分析,不能确定岩石孔隙结构变化规律。本文通过石英玻璃管封装块状样开展页岩生烃热模拟实验,并结合一套数据处理方法,尝试建立了一种适合页岩气研究的热模拟实验方法,研究泥页岩在不同演化阶段(Ro范围为0.596%~2.143%)不同赋存状态气体的含量以及岩石微观孔隙特征的变化情况。结果表明,泥岩及油页岩样品的排出气及解析气含量在高成熟度阶段(400℃以后)有明显增加的趋势,结合扫描电镜微观结构分析显示这是由于有机质生气量以及无机孔隙均有增加。本方法可以研究页岩热演化过程中不同赋存状态气体含量及微观孔隙结构的变化,为页岩气勘探开发提供了一种可参考的方法。     

The lateral and vertical reflectance and petrological variation of a heat-affected bituminous coal seam from southeastern British Columbia, Canada

Thermally altered pods of coal of very high rank have been observed in a high-volatile-bituminous coal seam in the eastern side of Eagle Mountain, Elk Valley Coalfield, British Columbia. Rank changes have been measured over a strike distance of 7.5 m from 1.24% to 7.1% R_{o max}, corresponding to a rank gradient of 0.78% R_om⁻¹.Petrologically, unaltered to extremely altered vitrinite showing nongranular (basic) anisotropy, mosaic-textured liptinite and pyrolytic carbon are the most abundant components. The limited presence of mosaic on vitrinite is an indication that the coal seam may have been weathered prior to being heat-affected.Evidence points to localized temperatures as high as 1,000°C, which could have been caused by a lightning strike. The eastern side of Eagle Mountain has experienced higher temperatures than the western side, and it appears that the heat ‘front’ and zone of alteration have an irregular pattern, pointing to saturation of parts of the coal seam by water.Four types of pyrolytic carbon having distinct morphology, anisotrophy and optical path with increasing temperature were observed. Reflectance of pyrolytic carbon falls within the zone of heat-affected coals, whereas the optical path of heat-affected Seam 15 samples is different from that of fresh coal with increasing rank.Finally, the reflectance of vitrinite in heat-affected coal is higher than the reflectance of vitrinite in carbonaceous shale in the Seam 15 section.