Cyclic characteristics of sediments in the Moon Island Beach Subgroup, Newcastle Coal Measures, New South Wales

Cyclic characteristics of a sequence of Permian coal-measure sediments have been studied using Markov chain analysis on borehole data. Fining-upwards and oscillating sequences can be distinguished, and depositional regimes are proposed to explain the observed sequences. However, there is no clearly defined relationship of sequence type to tectonosedimentary environment. The relationship of the number of coal-defined and fining-upwards cycles to total thickness and mean cycle thickness is examined using linear regression. The relationships for coal-defined and fining-upwards cycles are essentially the same. Significant positive correlations are present between the number of cycles and total thickness and significant inverse relationships are present for the number of cycles and the mean cycle thickness.     

Use of time-trend curves to interpret depositional environments in portions of the Chickamauga Group carbonates (Middle Ordovician, northeastern Alabama)

Data from point counts of 376 thin sections from six stratigraphic sections in the Chickamauga Group carbonates (Middle Ordovician of northeastern Alabama) were smoothed by time-trend methods. The resulting curves were plotted against the stratigraphic sections to show depositional trends and to facilitate interpretation of depositional environments. The depositional environments in the lower third of the sequence studied were dominantly subtidal; in the middle portions they were interbedded subtidal, intertidal, and supratidal; in the lower upper third they were supratidal; and in the uppermost portions they were interbedded subtidal, intertidal, and supratidal. Time-trend methods proved to be useful in this study, for they are easy to use and eliminate much noise observed in the data, whereas preserving major trends. Correlation between outcrops was by means of two continuous bentonites; comparison of the time-trend curves show that they would have been useful for correlation if the bentonites had been absent, although small differences in the vertical positions of beds between localities (indicating lateral migration of environments) would not have been detected by time-trend methods.     

内蒙古早白垩世五间房含煤盆地煤层煤相分析

内蒙古是我国非常重要的后备煤炭资源基地,煤层大多聚集在白垩纪断陷盆地中,其中,五间房含煤盆地煤炭资源丰富。通过对该盆地东南部3个钻孔57件煤样的煤岩学和煤化学分析,探讨了煤层的煤质特征、煤相类型及其演化规律。研究结果表明：本区煤层以低—中高灰、高挥发分产率和低—特低硫为特征;具有较高的镜/惰比和结构保存指数;煤相类型主要为潮湿森林沼泽相,自下而上,成煤泥炭沼泽覆水程度总体有所加深,上部泥炭沼泽具有水体逐渐加深的水进型特征,下部泥炭沼泽具有水体逐渐变浅的水退型特征。     

不同成因类型煤的可选性评价

煤的可选性受控于煤的聚积环境。通过对内蒙古乌达矿区主采煤层9、10、12、13和15煤中黄铁矿和粘土矿物的赋存特征与煤层成因关系的研究,发现河控下三角洲平原形成的煤层中黄铁矿含量低,粘土矿物含量高,其可选性较好;潮控下三角洲平原形成的煤层,其硫分含量高,粘土矿物含量较低,其可选性中等,而在潮坪沉积基础上形成的煤层中黄铁矿和粘土矿物的可选性最差。     

中国特高挥发分特高油产率煤的分布及其特征

基于全国煤炭资源潜力评价和全国特殊及稀缺煤炭资源调查项目成果,结合前人的研究,采用保有储量加权平均法,分析我国不同省份、不同成煤时代煤炭资源的挥发分产率和焦油产率以及特高挥发分、特高油产率煤的分布和成因。结果显示：我国煤炭资源的挥发分产率储量加权平均值为30.27%,以中高-高挥发分煤为主,焦油产率储量加权平均值为7.66%,以富-含油煤为主;我国特高挥发分、特高油产率煤的保有资源储量约占全国煤炭保有资源储量的0.9%,主要为褐煤、长焰煤、气煤和气肥煤;含有腐泥煤和腐植腐泥煤夹层的煤和残植煤因富含壳质组分具有较高的挥发分产率和焦油产率;对于同一煤类,挥发分产率和焦油产率都与氢含量和氢碳原子比呈正相关关系。     

近海型含煤岩系沉积学及层序地层学研究进展

层序地层学是近20年来发展起来的一门新的方法学科,并在聚煤作用分析中得到广泛应用。作者就近海型含煤岩系沉积学研究历史以及煤系层序地层学研究方法及有关问题进行探讨,认为近海环境的聚煤作用实际上是海平面(基准面)上升过程中发生的,同时提出煤层厚度受泥炭堆积速率与可容空间增加速率的控制：靠陆一侧冲积平原和三角洲平原沉积环境中,厚煤层主要出现在最大海泛面位置;而靠海一侧障壁-潟湖或碳酸盐岩台地沉积环境中,厚煤层主要出现在初始海泛面的位置;但就整个三级复合层序来说,层序中厚度最大、分布最广的煤层主要分布于可容空间增加速率最大的最大海泛面附近的位置。对于中国晚古生代近海型煤系中常见的“根土岩-煤-石灰岩”序列,聚煤作用发生于海相石灰岩“滞后时段”,即在海侵之后、海相石灰岩层真正沉积下来之前的时段,这一时段可容空间增加速率与泥炭堆积速率平衡,有利于聚煤作用发生。     

韩城桑树坪二号井松软煤层钻进技术研究与实践

针对韩城桑树坪二号井煤层松软破碎,现有设备能力小、自动化程度低、钻探工艺不合理导致瓦斯抽采钻孔钻进深度浅、钻进效率低等问题。对研究矿区3号煤层进行了大螺旋钻杆回转钻进、宽翼片螺旋钻杆空气钻进与宽翼片螺旋钻杆清水钻进工艺试验。试验表明：宽翼片螺旋钻杆清水钻进工艺施工效率是原来的1.5倍,钻孔深度由80 m左右提高到了200 m以上,成孔率达80%以上,满足了桑树坪二号井工作面瓦斯抽采钻孔施工要求。     

重庆中梁山矿区主要煤层的煤岩学和煤相特征

结合国际煤岩学会（ICCP）对显微组分的新分类系统,通过绘制显微组分三元图和煤相图,对重庆中梁山矿区主要煤层显微组分和煤相特征进行了研究。结果表明：该矿区宏观煤岩类型以半亮煤为主,且构造煤较发育;显微组分中以镜质组为主,其中以基质镜质体和碎屑镜质体最为常见。煤相研究表明,本区主要煤层形成于下三角洲平原或下三角洲平原到陆相沉积的过渡环境,属于近陆相的低位沼泽环境,成煤环境受海水作用明显。     

Entropy in Markov analysis of late paleozoic cyclical coal measures of East Bokaro basin, Bihar, India

Randomness in the occurrence of lithologies in a cyclical succession is evaluated in terms of entropies which can be calculated from a Markov chain matrix. Two types of entropies are linked with every lithologic state; one is the entropy before deposition E ^(pre) and the other is that after deposition E ^(post),which together form an entropy set. The entropy sets for pebbly sandstone, sandstone, shale, and coal for the Karharbari coal measures, and sandstone, shale, carbonaceous shale, and coal for the Barakar coal measures were plotted separately and compared with Hattori's idealized plots. These coal measures probably were essentially of symmetrical cyclical pattern (Type-B)of Hattori. The entropy of the whole sedimentation unit readily fits under the broad framework of fluvial cycles.     

多煤层对比方法优化研究

当前,我国煤炭开采向西部地区转移接续是必然趋势,针对西部分布最为广泛的侏罗系中统延安组陆相含煤沉积建造存在的多煤层对比依据缺乏、多解的难题,联合高精度地震勘探和数字测井技术,利用煤、岩层物性响应标志,结合陕北侏罗纪煤田阿包兔地区勘查工程实践,开展陆相多煤层精细对比工作,探讨并构建了陆相含煤建造多煤层对比方法组合模式,形成了7类12项方法组合的架构体系,并提出了相应的工作程序和实施原则。应用研究表明,加强物探资料综合分析,深挖利用煤岩物性标志、重视利用组合标志可有效提高煤层对比的可靠程度,这对于煤矿资源合理开发和勘探生产保障具有现实意义。     

陕北某矿双煤层开采对覆岩影响的模拟对比

多煤层开采条件下煤层覆岩破坏具有独特的特征,影响矿井生产布置。以陕北某矿为例,以该矿地质采矿条件为基础,采用相似材料模拟实验与数值模拟相结合的方法,通过建立模拟模型,开展了双煤层开采对覆岩的破坏影响研究。结果显示：留设不同宽度的煤柱,采用相似材料模拟和数值模拟2种方法得到的煤层覆岩垮落带高度、裂隙带高度都基本一致;在双煤层开采时,留设的煤柱宽度越大,两个煤层的叠置区域就越小,煤层开采对覆岩的破坏程度就越小。在工作面布置时,建议增大两个煤层的开采距离,并尽量增加煤柱宽度,以减缓覆岩移动破坏范围和破坏程度。研究成果为类似双煤层开采工作面的设计及覆岩破坏控制提供技术支撑。     

煤地质学研究进展与前沿

煤地质学是以煤的形成、组成、煤系伴生矿产、煤层瓦斯和煤层气为主要研究内容的地质学分支。近年来随着我国和世界对煤炭资源安全开采、洁净利用的要求逐渐提高,煤及煤层气资源的勘探与开发,煤地质学的研究重点也在逐渐发生变化。通过分析2011-2015年《国际煤地质学》杂志发表的717篇学术论文,总结了近期煤地质学最新的研究热点与前沿。研究发现：煤层气资源评价以及与煤层气开发关系最为紧密的煤储层物性研究是各国煤地质科技工作者最为关注的热点;煤中的矿物质和元素地球化学一直为人们所重视;与煤的形成、开采和利用相关的煤岩学及有机地球化学,煤的自燃、燃烧与环境,沉积环境与煤炭演化,地理信息系统与矿区环境监测,矿井瓦斯,矿井构造,矿井水和煤的热解等方面的研究一直在持续开展;页岩气资源评价与开发越来越受到人们重视。     

厚煤层内小断层的反射槽波探测技术及应用

厚煤层、巨厚煤层工作面内的小断层一般断距或延展长度的规模较小,目前的探查方法和仪器受分辨率限制一般难以探查这类小断层,而小断层探查不清,将会对智能化工作面高效回采带来较大影响。针对这一问题,开展厚煤层内小断层反射槽波探测的数值模拟及现场实验工作。在数值模拟方面,采用交错网格有限差分法对厚煤层(6 m)、巨厚煤层(20 m)两种环境下含小断层(落差小于3 m)的数值模型进行三分量弹性波模拟,在对数值模拟结果进行频谱分析的基础上研究不同模型中的直达槽波与反射槽波的特征。在实际探查方面,通过不同矿区厚煤层、巨厚煤层实际发育断层进行透、反射数据综合研究,分析和比较透射与反射槽波方法对小断层的探查情况。研究表明,工面内构造发育相对简单的条件下,反射槽波对厚煤层、巨厚煤层工作面中小断层的探测较透射槽波有更强的识别性及准确性。      

煤相参数在煤层层序划分中的应用——以新疆准东煤田帐南西矿区为例

运用层序地层学原理和方法,利用钻探和测井资料以及煤的显微组分和煤相参数分析,对新疆准东煤田西山窑组的层序单元进行了划分,特别对煤层中的准层序进行了确定。研究结果表明：西山窑组为 1个三级层序,并由低位、湖扩和高位体系域构成;在煤层中确定了水进型、水退型 2种准层序类型以及缓慢水进型准层序组和相对快速水进型准层序组;湖扩体系域由水进型和水退型煤层构成,高位体系域由水退型煤层构成;煤层煤相总体为干燥森林沼泽。     

豫东地区岩浆活动对煤层结构及煤质的影响

为指导豫东地区煤矿合理部署、高效生产,基于大量钻井和测试资料的综合分析和对比研究,探讨了豫东地区岩浆活动的基本特征及其对煤层结构和煤质的影响。研究结果表明：燕山中晚期的岩浆活动对豫东地区的煤层结构和煤层连续性造成影响,导致煤层变薄、分叉、尖灭和吞噬;同时,岩浆活动导致本区煤层变质程度普遍增高,煤质参数发生变化。煤层的原始赋存状态、岩浆侵入的初始温度、侵入岩体的厚度、岩浆侵入煤层的方式、岩体离煤层的距离、围岩和岩体上覆地层的岩性等是影响煤层结构和煤变质程度的主要控制因素。     

Counting error in petrographic point-count analysis: A theoretical and experimental study

The binomial model, commonly used to estimate counting error in point-count analysis, misestimates this error when the observation points on a grid are positively or negatively correlated. A model, called the cell model, is proposed as an alternative to the binomial model for use in studies, especially with coarse-grained rocks, in which such correlation is known or thought to exist. In the new model the thin section is conceptually partitioned into a number of cells (six is recommended), and the assumption is made that the proportions in the individual cells are statistically independent and that their variance does not differ from cell to cell. Empirical relations obtained from a suite of 200 thin sections of limestones are in reasonable support of the prediction that large particle size adversely affects counting error estimates based on the binomial model.     

吐哈盆地煤层的吸附性及其影响因素

通过对吐哈盆地煤层的吸附性及其影响因素的深入研究,认为该盆地煤层虽然变质程度较低,但对甲烷气仍有较强的吸附能力;煤的变质程度是影响吐哈盆地煤层吸附性的主要因素,煤岩显微组分、煤中水分和含油性也对煤层吸附性有不同程度的影响。     

可控电脉冲波增透技术在低透气性煤层中的应用

可控电脉冲波增透技术作为低透气性煤层增透改造的理想措施之一,施工方案优化问题亟待解决。选择山西保德煤矿低透气性煤层,采用可控电脉冲波增透技术开展钻孔增透施工方案优化。试验结果表明,在钻孔内平均增透作业范围为131 m、冲击密度为0.5次/m条件下,增透钻孔组日均瓦斯抽采量较常规孔提高4.7倍,可控电脉冲波增透效果最佳。增透钻孔组日均瓦斯抽采量由高到低依次是5 m观测孔、15 m观测孔、30 m观测孔和增透孔,表明增透效果随着距离的增加逐渐衰减,影响半径确定为大于30 m。结合对比验证试验综合分析认为,可控电脉冲波能够显著提高煤层瓦斯抽采量,而冲击密度和钻孔内增透作业范围是增透效果的重要影响因素。在较硬煤层中以钻孔内平均增透范围100 m、0.5次/m冲击密度作业增透效果最佳。研究成果为可控电脉冲波增透技术在我国低透气性煤层的增透施工方案设计中提供参考。     

Fuzzy evaluation of powered support suitability to coal seams

Summary The selection of powered supports involves many geological factors where adequate data is lacking and in which subjective judgement is inevitable. This paper proposes one approach, a fuzzy multicriteria decision-making model, to transfer non-quantitative judgements into quantitative ones that computers can process. A detailed example is included to demonstrate how the model applied to evaluating the suitability of powered supports to coal seams.     

“特殊”煤光片制备及对煤岩分析的主要影响

煤岩分析在煤相研究、地质勘查、炼焦配煤等诸多方面有广泛应用;合格的煤光片是煤岩分析的前提。为解决易碎裂样品、老化煤光片等\