南太行山东麓煤田瓦斯突出主控地质因素分析

根据南太行东麓二1煤层煤与瓦斯突出特征,应用煤与瓦斯突出综合假说,从煤层瓦斯生成、运移、储存的角度,分析研究了岩浆热液作用、地质构造、煤层埋深等因素对煤层煤质、煤层生烃能力、瓦斯含量和压力等煤层瓦斯参数及瓦斯突出因素的影响,确定岩浆热作用对瓦斯突出具有严重影响作用,地质构造、煤层埋深等因素对瓦斯突出具有中等影响作用和一般影响作用,该结论为地质勘探、矿井设计与生产规划、矿井瓦斯防治提供了理论依据.     

顺煤层剪切带煤与瓦斯突出机理分析

为了确定顺煤层剪切带的煤与瓦斯突出机理,在对顺煤层剪切带的受力状态进行分析的基础上,应用Mohr-Coulomb理论研究了顺煤层剪切带的形成机制,并探讨了顺煤层剪切带内的煤层变化特征、瓦斯含量和瓦斯压力特征及地应力对煤与瓦斯突出的影响。结果表明:当煤层倾角接近剪切滑动的临界角时,易产生薄煤区,而远离临界角时,煤层厚度增加,煤层厚度剧烈变化部位为应力集中区并具有较高的应力梯度;顺煤层剪切带内的压应力、煤层的面理化结构和煤层厚度的剧烈变化使其在宏观上形成了高瓦斯含量和高瓦斯压力特征,微观上糜棱煤细颈瓶型的孔隙形态为发生煤与瓦斯突出提供了必要的介质条件;在紧闭褶皱区,煤与瓦斯突出类型以突出为主,在宽缓褶皱区和伸展型顺煤层剪切带内,煤与瓦斯突出类型以压出和倾出为主。顺煤层剪切带内的高地应力、高瓦斯压力和发育的构造煤等3个因素是煤与瓦斯突出发生的主要原因。      

河南省崤熊构造区主采煤层瓦斯地质规律

采用评价、校正后的174个可用钻孔煤层瓦斯含量点绘制了崤熊构造区主要煤田主采煤层瓦斯含量等值线图,通过分析比较各煤田瓦斯地质特征,总结了区域构造对煤层瓦斯分布的控制规律。崤熊构造区主要煤田主采煤层瓦斯含量总体较低,平均值基本在6 m~3/t以下。煤变质程度低,以长焰煤、气肥煤为主,导致煤层瓦斯含量总体偏低。崤熊构造区受秦岭造山带的影响,在先期逆冲推覆构造的基础上,叠加了后期的伸展构造,不利于煤层瓦斯的保存。     

上覆岩床对煤层瓦斯赋存特征的影响——以宣东二矿Ⅲ3煤层为例

根据宣东二矿Ⅲ3煤层实测煤质、煤层瓦斯数据,从煤层瓦斯生成、运移、储存角度,研究了上覆岩床对煤层煤质、煤层生烃量、瓦斯含量和瓦斯压力等煤层瓦斯赋存状态参数的影响,认为受上覆岩床影响,煤变质程度提高,由长焰煤变成气煤-焦煤,煤层Rmax、Cdar值与辉绿岩床厚度呈明显的正相关,与Ⅲ3煤层和辉绿岩床间距呈明显的负相关,煤层最大吸附瓦斯能力由15m3/t提高到40m3/t,煤层瓦斯含量由3m3/t提高到9m3/t以上,多方面改变了Ⅲ3煤层瓦斯赋存状态和地质条件.     

晋普山煤矿瓦斯赋存相关因素及涌出量预测

晋城矿区晋普山煤矿目前开采9煤层,煤层瓦斯含量高,经鉴定属高瓦斯矿井。利用井田地质勘查成果及井下瓦斯监测数据,对区内瓦斯赋存规律及涌出量进行了分析。结果显示:煤层煤类、褶皱构造和煤层围岩是其主要控制因素,而煤层埋深对瓦斯赋存影响不明显。按开采层和邻近层瓦斯涌出量叠加原理,采用分源预测法分别预测了9、15号煤层回采工作面瓦斯涌出量,其绝对瓦斯涌出量均大于5 m3/min,局部瓦斯含量较高,具有煤与瓦斯突出危险,建议矿井做好防范瓦斯灾害相应措施。     

黄庄勘查区二_1煤层瓦斯赋存规律及控制因素分析

针对黄庄勘查区二_1煤层埋藏较深、煤层稳定、结构简单,但瓦斯含量较低,并且分布不均衡,瓦斯含量差异较大,局部形成瓦斯聚集区的问题,对瓦斯赋存规律及控制因素进行研究。研究表明勘查区地质构造、煤层围岩是导致勘查区瓦斯含量相对较低的主要原因,地质构造、煤层埋深、煤厚是影响煤层瓦斯赋存形态的主要因素。研究瓦斯赋存规律,对防止煤与瓦斯突出、消除或降低煤与瓦斯突出事故造成的危害有很好的指导意义。     

黄河北煤田赵官井田煤层瓦斯赋存规律及主控因素

基于煤层瓦斯的生成、赋存、运移理论,结合地质勘探和矿井生产揭露的瓦斯地质资料,分析了山东黄河北煤田赵官井田煤层瓦斯赋存规律及其主控因素。从区域地质演化、煤的生储气能力、岩性组合特征、地质构造、埋藏深度、基岩厚度、水文地质条件和岩浆侵入等因素综合研究发现,影响赵官井田煤层瓦斯赋存的主控因素为地下水动力条件及岩浆侵入事件。地下水动力条件对煤层瓦斯的控气作用明显,浅部水动力条件对煤层瓦斯主要表现为水力运移逸散作用,不利于煤层瓦斯保存,向深部主要表现为封闭和封堵2种类型,有利于瓦斯的保存。岩浆侵入煤层的方式及其程度是造成下组煤（11号、13号煤）瓦斯含量普遍低于上组煤（7号、10号煤）的主控因素。      

地质因素对土城矿瓦斯赋存的控制作用

根据矿区大地构造位置、构造演化和区域构造应力场的特点,分析了土城矿构造特征及其对煤层瓦斯的控制作用,发现土城矿处于盘江矿区“三角形弧系”构造应力场作用下的强变形区内,发育的NE向、NW向断裂构造是矿井瓦斯赋存和构造煤发育的控制因素,大中型断层控制着矿井瓦斯赋存与分布,而小型构造是煤与瓦斯突出的控制因素。土城矿井田西部发育的大中型断裂形成了煤层瓦斯运移和逸散的通道,不利于煤层瓦斯的保存,导致该区域煤层瓦斯含量相对低;井田东部的断裂构造不发育,煤层整体上保存较为完整,煤层瓦斯含量整体较高。小型断层附近瓦斯富集、构造煤发育,尤其在断层上盘、断层尖灭端与断层交汇的地段,煤体破坏严重,是煤与瓦斯突出事故易发地段。土城矿瓦斯防治工作应分区域实施,井田西部应关注煤层瓦斯含量随埋深增大而增加的规律并及时防范深部区域可能出现的瓦斯灾害,而井田东部则应在强化对隐伏断层探测基础上优先实施开采保护层和抽采煤层瓦斯等综合治理措施。     

褶皱构造控制煤层瓦斯的基本类型

褶皱构造控制煤层瓦斯的赋存为多数研究者所承认。但从目前统计资料分析,背斜和向斜特别是它们的轴部及其附近,既有煤层瓦斯含量较高、或者发生瓦斯涌出或发生煤与瓦斯突出的现象,也有煤层瓦斯含量较低或不发生瓦斯涌出或煤与瓦斯突出(以下简称突出)的现象。      

穿层钻孔各煤层瓦斯抽采比例计算方法及应用

为了测定穿层钻孔多煤层瓦斯抽采各煤层瓦斯抽采比例及残余瓦斯含量,分别提出了相应的解决方法。计算穿层钻孔多煤层瓦斯抽采各煤层瓦斯抽采比例时,提出将煤层厚度、原始瓦斯含量、透气性系数的乘积作为瓦斯抽采相关量,将瓦斯抽采相关量归一化处理来计算,考虑了影响穿层钻孔瓦斯抽采的主要因素;预测穿层钻孔多煤层瓦斯抽采各煤层残余瓦斯含量时,利用原始瓦斯含量与吨煤瓦斯抽采量来计算,吨煤瓦斯抽采量与穿层钻孔瓦斯抽采总量、穿层钻孔在该煤层的瓦斯抽采比例及该煤层的质量有关。结果表明:提出的穿层钻孔多煤层瓦斯抽采各煤层瓦斯抽采比例计算方法,与贵州省青龙煤矿现场实测结果的最大相对误差仅为2.03%,能够满足工程实践的需要。      

川南古叙矿区煤层气资源有利区优选

川南煤田二叠系龙潭组是重要的含煤层系,也是煤层气的主要赋存层段。古叙矿区是川南地区煤矿主要产区,煤层气资源丰富,在大村矿段已实现工业开采,其他矿段尚处勘探阶段。依托区域矿产地质调查,在分析区域煤层展布特征基础上,优选区域分布稳定的煤层C25、C23、C19、C17、C11为古叙矿区煤层气勘探目的层段。目的层段普遍具有有机质组分含量高、灰分含量中-高、内生裂隙发育、含气性高的特征,煤层累计厚度呈东厚西薄展布。以煤层厚度、构造条件、埋藏深度为主要评价指标,优选出大村矿段、石宝矿段为煤层气富集有利区,观沙矿段观文井田、古蔺矿段石屏-象顶井田及河坝矿段白头沟地区为煤层气富集较有利区。     

Pollution of organic compounds and heavy metals in a coal gangue dump of the Gequan Coal Mine, China

Samples around a coal gangue dump of the Gequan Coal Mine were collected in April 2009. GC (gas chromatography) and GC/MS (gas chromatography/mass spectrometry) were employed to analyze the composition of organic matter in the samples. ICP-MS (inductively coupled plasma mass spectrometry) was used to determine the concentrations of heavy metals. The contents of organic extracts are within the range of 140-750 mg/kg. Alkand aro-ratios are relatively high. Compared to those of the background sample (GQ13 ), the contents of saturated hydrocarbon compounds in all the samples are relatively high. The contents of polycyclic aromatic hydrocarbons (PAHs) are relatively high with the distance getting closer to the coal gangue dump. These indicate that organic matter in the samples is from coal particles of the coal gangue dump. The distributions of heavy metals are very similar: the contents decrease with distance from the dump, which indicates that the harmful heavy metals from the coal gangue dump have polluted as thick as at least 500 m.     

Simulation of an enhanced gas recovery field trial for coal mine gas management

Coal mine gas management has evolved from being predominantly dependant on mine ventilation systems to utilising sophisticated surface based directional drilling for pre-drainage of coal seams. However the advent of enhanced gas recovery techniques in the coalbed methane industry has provided an opportunity to address gas management objectives hitherto impractical. Specifically: achieving very low residual gas contents to mitigate against frictional ignitions and fugitive emissions; the means to accelerate gas drainage to accommodate mine schedule changes; and to enable pre-drainage of coal reserves with very low permeability. This article examines a possible enhanced gas recovery field trial at an Australian mine site. Production data from four surface to inseam medium radius gas drainage boreholes was modelled and history matched. The resulting reservoir characteristics were then used to model the performance of the boreholes using an enhanced recovery technique. One of the boreholes is modelled as an (nitrogen) injection well and two flanking wells are modelled as production wells.The model results suggest that accelerated gas flow rates as well as very low residual gas contents are achievable using typical coal mine gas drainage infrastructure and goaf inertisation systems.     

煤中残余气含量及其影响因素

煤中残余气是煤层气的一个组成部分,其含量直接影响到煤层气含量和煤的含气饱和度。本文对不同地区、各种煤级的近100 个煤心煤样的残余气含量测试结果进行了综合分析研究,找出了煤中残余气含量的分布变化规律,探讨了其影响因素。结果表明:不同煤的残余气含量不相同,变化范围为0~3 m3/t;残余气在煤层气中占的比例变化很大,为1.5%~30.0%;残余气含量的高低受煤级、灰分和煤样粒度等因素影响,煤级和灰分越高,残余气含量亦越高      

Application of in-seam directional drilling technology for gas drainage with benefits to gas outburst control and greenhouse gas reductions in Daning coal mine,China

Gas outburst disasters are becoming more serious as the underground coal mines become deeper in China, and a thick zone of deformed coal provides conditions favorable to coal and gas outbursts. The Daning coal mine’s main mining seam is the No. 3 coal seam with coal and gas outburst hazard, which often contains two normal coal sub-layers and one deformed sub-layer. Considering both the geological conditions of the coal seam and applications of the in-seam directional longhole drilling technology, a new schematic diagram of in-seam directional longholes for gas drainage is developed. The two borehole layout models of longwall panel and main entries for gas outburst disasters control have been successfully applied. The gas drainage rates of both models are >70 %, and the residual gas contents are both <8 m³/t, which can be considered that the gas outburst disasters were effectively controlled. To better guide gas drainage, gas drainage normal and failure modes have been obtained. Although in-seam directional longhole technology has been successfully applied for regional gas drainage with benefits to gas outburst control, there are also some problems that are detrimental to greenhouse gas reductions in gas drainage and gas utilization. The three main problems are air leakage failure in gas drainage, decreasing gas concentration and a low gas utilization ratio. To address the problems mentioned above, five improvements are suggested.     

Isotopenvariationen des Stickstoffs humoser und bituminöser natürlicher organischer Substanzen

gd¹⁵N-values and nitrogen contents of a series of humic and bituminous organic sediments of different ranks were determined. The change of the isotopic abundance of nitrogen was investigated during heating in model experiments, using a gas flame coal.In the case of humic carbon coals the relative nitrogen contents vary from 0.8 to 1.4% and the δ¹⁵N-values from +3.5 to +6.3%. increasing from the brown coal to anthracite ranks. During the coalification process both the δ¹⁵N-values and the relative nitrogen contents do not vary continuously with the rank, but pass through maxima and minima. Model experiments using a gas flame coal show the same trend. Nitrogen with δ¹⁵N-values of +2.8 or ?7%. was released in pyrolysis experiments, applying a gas flame coal and a steam coal at temperatures of 650 and 1000°C, respectively.The investigated bitmuinous sediments yielded relative amounts of 0.1 to 0.8% with δ¹⁵N-values of + 4.2 to + 10.7%.The obtained results are discussed with respect to the elucidation of nitrogen genesis in natural gas deposits.     

Development of the first coal seam gas exploration program in Indonesia: Reservoir properties of the Muaraenim Formation, south Sumatra

The Late Miocene Muaraenim Formation in southern Sumatra contains thick coal sequences, mostly of low rank ranging from lignite to sub-bituminous, and it is believed that these thick low rank coals are the most prospective for the production of coal seam gas (CSG), otherwise known as coalbed methane (CBM), in Indonesia.As part of a major CSG exploration project, gas exploration drilling operations are being undertaken in Rambutan Gasfields in the Muaraenim Formation to characterize the CSG potential of the coals. The first stage of the project, which is described here, was designed to examine the gas reservoir properties with a focus on coal gas storage capacity and compositional properties. Some five CSG exploration boreholes were drilled in the Rambutan Gasfield, south of Palembang. The exploration boreholes were drilled to depths of ~ 1000 m into the Muaraenim Formation. Five major coal seams were intersected by these holes between the depths of 450 and 1000 m. The petrography of coal samples collected from these seams showed that they are vitrinite rich, with vitrinite contents of more than 75% (on a mineral and moisture free basis). Gas contents of up to 5.8 m³/t were measured for the coal samples. The gas desorbed from coal samples contain mainly methane (CH₄) ranging from 80 to 93% and carbon dioxide (CO₂) ranging from 6 to 19%. The composition of the gas released into the production borehole/well is, however, much richer in CH₄ with about 94 to 98% CH₄ and less than 5% CO₂.The initial results of drilling and reservoir characterization studies indicate suitable gas recovery parameters for three of the five coal seams with a total thickness of more than 30 m.     

远红外作用下不同含水率煤体吸附/解吸能量变化规律

煤体对气体进行吸附/解吸过程的本质是气体分子和煤基质表面分子或原子相互作用的过程，而发生相互作用的本质是能量变化，为了深入研究远红外作用下煤层气吸附/解吸过程及能量变化规律，利用自主研制装置进行远红外作用下不同含水率煤样对CO₂的吸附/解吸实验，然后利用远红外热辐射原理所得的吸附/解吸能量公式对实验结果进行计算，得到不同含水率煤体吸附/解吸过程能量变化规律。结果表明:在远红外作用下，解吸率虽然随含水率增大呈下降趋势，但是下降幅度明显减小，远红外作用可以降低水分对煤层气吸附/解吸能力的影响；远红外作用下不同含水率煤体对气体吸附/解吸过程是一个物理变化，从能量角度可以解释该过程，其变化规律与等温吸附/解吸过程相吻合。研究结果丰富了煤层气增产技术理论。      

Effects of igneous intrusions on coalbed methane potential, Gunnedah Basin, Australia

The Gunnedah Basin, NSW, Australia, contains more than 500 Gt of coal, and has been the subject of recent coalbed methane exploration. Large areas of the basin contain igneous intrusions and large areas of coal have been heat-affected as a consequence. A detailed study has been undertaken of coal seams intersected in a cored coalbed methane exploration drillhole in which two sill-form igneous intrusions are present. Comparisons are made between coals that are unaltered and coals that have been heat-affected, using petrographic and chemical data, coal seam gas desorption data, and gas chemical analysis data.Results demonstrate that the two igneous intrusions have had a very positive effect on coalbed methane development. The gas content in a number of heat-affected coal seams within thermal aureoles above and below the sills is substantially higher than in adjacent unaffected coal seams. In addition, the intrusions have had little effect on gas quality. The coals in the heat-affected zone were found to contain gas with approximately 95% methane. The coals in the thermal aureoles were found, under the microscope, to contain characteristic micropores and slits, which collectively may serve to enhance gas adsorption capacity, permeability, and gas desorption. Gas contents below each of the sills is substantially higher than above the sill, confirming earlier results that the sills appear to have acted as a reservoir seal, during and for some time after intrusion. The background coal rank in ACM Yannergee DDH 1 is in the high-volatile bituminous range. The igneous intrusions have resulted in an increase in rank such that large areas of coal have moved into the optimal thermogenic gas generation window. This rank increase has affected a major part of the coal-bearing sequence.     

潍北凹陷孔店组天然气成因类型及分布规律

根据天然气组分以及碳同位素和轻烃特征等资料,运用天然气成因理论并结合天然气成因类型判识图版和成藏条件,探讨了潍北凹陷孔店组天然气成因类型及分布规律。结果表明：潍北凹陷天然气CH4体积分数大,重烃体积分数小,非烃组分极少;南部斜坡带的疃4井天然气属生物气;灶户鼻状构造带南部产出的天然气为混有生物气的油型伴生气;灶户鼻状构造带中部地区属典型的油型伴生气;北部洼陷区的东部和南缘产出的天然气具有煤型气,并有油型气混入;以昌1井为代表的北部深洼陷区是煤型气发育的有利地区。总之,潍北凹陷天然气可以划分为生物气、混有生物气的油型伴生气、典型的油型伴生气、混有油型气的煤型气、典型的煤型气等5种成因类型;孔店组天然气类型多样、分布复杂,这些与该区的烃源岩类型、成熟度等因素有关。