共查询到19条相似文献，搜索用时 140 毫秒
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不同煤级煤及其萃余物吸附性能的研究 总被引：7，自引：0，他引：7
采用不同溶剂对褐煤、焦煤、低级无烟煤(Ro,max2.62%)以及中级无烟煤(Ro,max3.74%)等四个煤级煤样进行分级超声萃取,然后对原煤和萃余物进行平衡水预湿的方法,进行了等温吸附实验,并结合孔隙结构测试和水分含量变化,分析了溶剂萃取后萃余物的吸附性能变化及其影响因素。研究发现:(1)平衡水条件下,原煤对甲烷的吸附能力要大于萃余物,萃取后,尽管煤的组成和孔隙结构发生了变化,但并不能改变不同煤级煤吸附甲烷的能力的对比关系;(2)原煤和各级萃余物都发生了到某一压力后,吸附量随着压力增加而下降的现象,褐煤及其萃余物甚至出现负值,这可能是由超临界状态下吸附相的体积忽视后带来的效应和煤基质在压力、水分作用发生膨胀以及随着压力增加,水分在吸附孔隙中占据吸附点位的增多,造成甲烷有效吸附点位的减少等综合作用的结果。研究认为,在讨论影响不同煤化作用的煤吸附能力的因素时,应该首先考虑到煤级对吸附能力的影响;对煤化程度相近的煤,其他因素如孔隙结构和水分的变化对吸附的影响才显现,但对不同煤级煤吸附性的主要影响因素也不尽相同。在煤层气吸附研究中,吸附量下降现象应该是一个共性,其机理的解释和寻求正确的吸附相体积校正,以及一定压力下,煤基质在水分作用下发生膨胀对吸附性的影响的规律描述,都是亟待解决的重要问题。 相似文献
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摘 要 通过对湘中南龙潭煤系不同煤级煤样的煤岩学和有机地球化学研究概括了湘中南
龙潭煤系煤的有机显微组成和主要有机地球化学特征指出其中的气煤、肥煤和焦煤是具有
较高生烃潜力的烃源岩壳质组和基质镜质体是这一阶段煤中的主要生烃组分。 相似文献
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再论煤中大分子基本结构单元演化的拼叠作用 总被引：3，自引：0，他引：3
芳构化作用和环缩合作用的传统煤化作用理论具有一定局限性,煤中基本结构单元拼叠作用是高煤级煤演化的特有机理。拼叠作用显著发生的起点位于镜质组最大反射率Ro,max为6．0％附近,大分子化学键的均裂提供了拼叠作用得以实现的微化学环境条件,其实质是一种“动力化学”过程,与氧接芳碳等有关的大量“均裂”是在短暂的煤化阶段中突然出现的,导致“拼叠作用”的显著发生具有“阶跃式”特征,是造成高煤级煤中期到后期阶段大分子基本结构单元急剧增大的根本原因和主要地球化学机理。 相似文献
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煤是一种对温度、压力等地质环境因素特别敏感的有机岩。煤化作用实质上是煤与外界进行能量和物质交换的一个开放系统。地质历史演化过程中的各种构造 热事件必然导致煤发生一系列物理、化学、结构和构造变化,煤中有机组分和无机组分在各种地质营力作用下迁移、分异和改造,从而影响煤层现今赋存状况、煤化程度和煤质特征,在一定程度上记录了沉积盆地动力学过程的地质信息。文中介绍了国内外在煤化作用与构造 热事件的耦合效应方面的研究进展,讨论了存在的问题,提出了重点研究课题。 相似文献
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煤体性质对煤吸附容量的控制作用探讨 总被引：6，自引：2，他引：4
煤体性质是影响煤吸附容量的重要因素之一。通过对中国华北和西北两个重要煤层气富集区煤的煤岩学、煤化学和等温吸附实验分析,从煤级、显微组分、煤体变形三个方面对煤的吸附容量及其控制因素进行了, 分析探讨。结果表明,水分平衡条件下煤的吸附容量与煤阶的关系为倒U字型,吸附容量随煤阶的变化为跃变式, 基本与四次煤化作用跃变阶段相对应,主要受控于煤化作用过程中煤的亲甲烷能力和孔隙度的变化;煤体中惰质组含量较高时,其对煤体的吸附容量的影响较为明显,主要与惰质组中丝质体的高吸附能力有关;在构造应力作用下,煤体表面物化发生的变化使构造煤吸附容量比同一矿区同一煤层原生结构煤高。 相似文献
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为了研究不同煤体结构煤的吸附行为差异和作用机理, 以焦作煤田为研究区, 对煤体破坏严重的糜棱煤和原生结构煤的岩石学组成、吸附性和孔隙性进行了测试, 结果表明: 煤体破坏后, 吸附、解吸能力增大; 温度增加, 煤的吸附能力均为下降, 解吸能力增加.相比于原生结构煤, 随着温度增加, 糜棱煤吸附能力下降趋势和解吸能力增大趋势比原生结构煤更为明显.研究认为: 煤体破坏后, 不同孔径段的孔隙数量均有增大, 使得煤样容纳气体的能力增大.特别是大中孔含量的增大, 导致了糜棱煤样更容易发生解吸.另外, 煤体破坏后的煤级增高、镜质组含量增大和惰质组含量减小也对吸附能力增大具有重要作用, 而灰分含量不是决定两类煤吸附性差异的主要因素. 相似文献
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埋藏史、受热史和有机质成熟史(简称"三史")模拟技术已广泛应用于油气地质研究,但其在煤和煤层气地质领域则应用较少。根据实测煤的镜质组最大反射率、古地温梯度和地层残余厚度等资料,运用Petromod 1D模拟软件对贵州织纳煤田水公河向斜上二叠统8煤层"三史"演化过程进行研究。结果显示,水公河向斜地质演化史可分为3个阶段:第1阶段从晚二叠世至侏罗纪末,煤层埋深增加,最大至5 925~5 959 m,地温梯度为2.91/hm℃,受深成变质作用影响,煤级从褐煤演化至焦煤阶段;第2阶段从侏罗纪末至白垩纪末,受燕山运动影响,煤层埋深降低,地温梯度为3.29~3.46/hm℃,区域岩浆热变质作用使煤级从焦煤演化至无烟煤阶段;第3阶段从白垩纪末至今,地层少量沉积后发生抬升作用,地温梯度为2.78℃/hm,煤化作用基本停止。总之,深成变质作用是向斜煤层气生成的主要影响原因,距今230~170 Ma是煤有机质生烃的关键时期。 相似文献
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采用二氧化氯溶液浸泡、甲烷等温吸附、X射线衍射等方法,探讨了煤储层改造新原理,从大分子结构层次上讨论了其可能的地球化学机理。实验结果显示,煤经浸泡后其吸附常数发生了明显变化,含气饱和度、临界解吸压力等得到不同程度的提高,但提高的程度受煤级控制。经二氧化氯处理后,煤中大分子结构单元发生了程度不等的解聚作用,煤大分子结构与吸附性之间存在同步响应关系,二氧化氯残液中存在苯环等有机物,解聚程度与煤化作用程度有关。浸泡后,煤分子结构发生了改变,使得其表面性质出现变化,从而影响到煤对甲烷分子的吸附能力和煤层气解吸产出潜势。 相似文献
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超临界二氧化碳（ScCO2）–H2O–煤地球化学反应可造成煤物理结构和化学结构的改变,对煤层注CO2增采甲烷的有效性尤为关键。为了探讨ScCO2-H2O-煤反应对不同变质程度煤化学结构的影响,选择3个不同煤化程度煤样,在自主研制的ScCO2-H2O-煤地球化学反应模拟实验装置中模拟1000m埋深条件下煤样与ScCO2和去离子水反应240h,并对反应前后的煤样分别进行了X射线衍射和拉曼光谱实验,对比分析了反应前后煤样晶体结构和碳有序度的变化特征。测试结果表明:ScCO2-H2O反应破坏了煤的晶体完整性和碳有序度,改变了煤的大分子结构,且对低阶煤和中–高阶煤具有不同的影响,反应提高了低阶煤的平行定向程度,使其结构更加紧凑,减小了面网间距,而使中–高阶煤中无序单元增加,面网间距增大。该研究结果为CO2-ECBM项目实施中ScCO2-H2O作用对煤储层吸附解吸特征和孔渗特征影响的研究奠定了微观尺度基础。 相似文献
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我国2 000 m以浅的焦煤煤层气资源量约1.214 7×1012 m3,占全国煤层气总资源量的3.3%,主要分布在华北、西北和西南等三大含气区。为了评价我国焦煤煤层气资源潜力,收集和测试了全国范围内的82件焦煤煤样的煤岩、煤质、工业分析、压汞实验和等温吸附实验数据,研究结果表明:随着煤化程度的增加,焦煤碳元素质量分数增加,而挥发分、氧元素和氢元素逐渐减小,且氧元素减少的速度大于氢元素;焦煤大孔、小孔和微孔较为发育,中孔发育较差;比表面积主要集中在小孔和微孔,大孔和中孔对比表面积的贡献甚微;焦煤孔隙度和总孔容与煤阶之间显示出"U"型关系,当1.20%max<1.40%时,焦煤的孔隙度和总孔容随着煤化程度的增加而减少,在Rmax=1.40%附近孔隙度和总孔容达到最低值,当1.40%max<1.70%,孔隙度和总孔容随着煤化程度的增加而增大;焦煤饱和吸附量平均约20.79 cm3/g,Langmuir压力随着煤化程度的增加而减小,Langmuir体积随着煤化程度的增加而增加。 相似文献
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页岩气主要以吸附和游离状态贮藏在海相、陆相和海陆过渡相泥页岩中,这些岩石的沉积过程、时间和类型不同,表现出了地层或岩石的物理化学性质各向异性的特点。页岩气钻探所遇地层主要是不同时代的泥岩、砂岩、泥质砂岩、砂质泥岩等,这些岩石对钻井液中水分子具有极强的敏感性。所以,在钻探过程中常遇到起下钻遇阻、孔内沉渣多、重复破碎、卡钻等问题,由此花费大量的时间处理,从而减少了纯钻时间。这些问题的根本原因则是由于岩石膨胀缩径、孔壁崩塌超径所造成的。本文首先对河南中牟页岩气区块地层特征进行了描述,并就牟页1井钻探问题从钻孔缩径和超径2个方面进行了理论研究和分析,最后从钻井液和钻探工艺选择方面提出了原则性的建议。 相似文献
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At present,artificial freezing method has become one of the effective methods for coal mine shaft to pass through water-rich soft rock strata,which can stop the movement of groundwater and limit the deformation of surrounding rock. In order to study the frost heaving characteristics of sandstone under different freezing conditions,frost heaving tests of saturated and dry Cretaceous red sandstone samples under different freezing rates （10 ℃·h-1,5 ℃·h-1,2 ℃·h-1,1 ℃·h-1）and different confining pressures（5 MPa,10 MPa,15 MPa,20 MPa,25 MPa）were carried out by using GCTS（Geotechnical Consulting & Testing Systems）servo-controlled low temperature and high pressure triaxial rock testing system. In this paper,based on the existing theory of physical and mechanical properties of frozen soil,we studied the frost heaving law of sandstone under different freezing conditions and explored the frost heaving mechanism. The result shows that in the process of cooling,the dry rock sample always produce cold shrinkage deformation,while the saturated rock sample first produce cold shrinkage deformation,then produce frost deformation,and finally the deformation tends to be stable. The deformation of saturated rock samples is much larger than that of dry rock samples. The larger the stress level of rock samples at the same temperature is,the smaller the frost deformation is,which shows a linear negative correlation,mainly because the high confining pressure limits the volume expansion of the water phase in the pore inside the rock samples when it becomes ice. The frost deformation of rock samples is mainly affected by confining pressure and water content,while the frost heaving rate is mainly affected by cooling rate. Under this test condition,the higher the cooling rate of sandstone is,the higher the frost heaving rate is,and the relationship between them is approximately linear. For saturated rock samples,the confining pressure reduces the rock frost heaving by limiting the expansion during the phase transformation of ice water,and the temperature affects the rock frost heaving by affecting the freezing rate of pore water and the thermal expansion and cold contraction of rock skeleton. For dry rock samples,the deformation is mainly due to the volume contraction of rock mineral particles caused by thermal expansion and cold contraction effect,and the greater the temperature change,the greater the deformation. Based on the experimental results and theoretical analysis method,a calculation formula of rock frost heaving considering the influence of confining pressure was established. By calculating the frost heave of sandstone samples under different confining pressures,it is found that the calculated values are in good agreement with the experimental results. Moreover,according to the calculation formula of frost heaving,the influence factors of rock frost heaving during freezing can be divided into two categories：internal cause and external cause. The internal cause includes porosity,saturation,volume modulus of ice and rock skeleton,and the external cause includes temperature and confining pressure. For saturated rock,the frost heaving is mainly affected by factors such as confining pressure,temperature and porosity. When the saturation,porosity and freezing rate are low,the rock may only produce shrinkage deformation,because these indicators determine whether the rock produces frost heave or freeze shrinkage. The mechanism of rock frost heaving is very complicated due to the interaction and restriction between the internal and external factors and the dynamic changes of rock micro-structure and mechanical properties during the process of frost heaving. The research results can provide theoretical reference for freezing construction scheme design of deep coal seam mine construction,and also provide a theoretical basis for the study of physical and mechanical properties and engineering application of soft rock in frozen soil area. © 2022 Science Press (China). 相似文献
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HAN Hui LIU Pengwei DING Zhengang SHI Pitong JIA Jianchao ZHANG Wei LIU Yan CHEN Shiji LU Jungang Chen Kang PENG Xudong WANG Zhiyong XIAO Shuqi GAO Yuan 《《地质学报》英文版》2018,92(4):1508-1522
To investigate the influence of extractable organic matter (EOM) on pore evolution of lacustrine shales, Soxhlet extraction, using dichloromethane, was performed on a series of Chang 7 shale samples (Ordos Basin, China) with vitrinite reflectance of 0.64% to 1.34%. Low‐pressure gas adsorption experiments were conducted on the samples before and after extraction. The pore structure parameters were calculated from the gas adsorption data. The results show complex changes to the pore volumes and surface areas after extraction. The pore development of both the initial and extracted samples is strongly controlled by total organic carbon (TOC) content. Micropores developed mainly in organic matter (OM), while mesopores and macropores predominantly developed in fractions other than OM. The influence of EOM on micropores is stronger than on mesopores and macropores. Organic solvents with a higher boiling point should be used to explore the effect of EOM on pore structure in the future. 相似文献
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基于气候变化和人类活动影响的土地利用分析——以新疆阿克苏河流域绿洲为例 总被引：4，自引：3，他引：1
以1990、 2000、 2010年3期Landsat TM影像为土地利用基础数据, 结合1990年以来的社会经济资料和反映气候变化的气温、 降水数据, 对1990年以来阿克苏河流域绿洲土地利用变化进行了分析. 结果表明: 1990-2010年期间, 耕地、 建设用地以单向转入为主, 耕地对绿洲"扩张"贡献最大, 前期(1990-2000年)的贡献率为129.1%, 后期(2001-2010年)的贡献率提高到142.5%; 草地、 水域以单向转出为主, 草地对绿洲"萎缩"贡献最大, 前期的贡献率是-39.8%, 后期是-34.8%; 其次是水域, 前期对绿洲的贡献率是-1%, 后期是-9.3%; 河漫滩、 林地、 湿地在前期对绿洲的"扩张"贡献率分别是7.5%、 0.3%和5.1%, 后期对绿洲的"萎缩"贡献率分别是-2.4%、 -0.02%和-0.4%. 近20 a来流域绿洲规模整体上持续扩张. 通过分析绿洲土地利用驱动力系统可以看出, 绿洲土地利用类型变化主要受人类活动影响, 气候变化起基础性作用. 相似文献
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A detailed study of petrological, geochemical, textural and coking properties was carried out on vitrains from the Puertollano, Blanzy–Montçeau, Asturias and Teruel. The objective was to determine in depth the physical and chemical properties of a series of natural and pure vitrinites of different rank, and the influence that the sedimentary and post-sedimentary conditions had on them. It is demonstrated that although vitrains are almost entirely made up of the huminite/vitrinite maceral group they have a different composition, thermal behaviour and physical properties. Thus, geochemical and textural properties of Blanzy–Montçeau vitrains can be considered to be representative of the telinite, the major component in both samples (75% vol.) at the beginning of the bituminization stage (subbituminous/high volatile C bituminous coals). The characteristics of the Puertollano vitrains described here can also be attributed to the telocollinite (>80% vol.) for the high volatile C bituminous coal. Variations in physico-chemical properties between Puertollano and Blanzy–Montçeau vitrains are due to the differences in the initial composition of organic matter. Slight differences (i.e., bed moisture content or porosity) between vitrains from the two coal seams in the same basin can be attributed to their stratigraphic position. Several parameters such as S2, HI, oil and extraction yield and fluorescent properties suggest that the Puertollano and Blanzy–Montçeau vitrains have a lower hydrocarbon potential. The relationships between geochemical and textural properties make it possible to distinguish between ‘normal' and perhydrous vitrains. The two different hydrogen-enrichment processes that occur in vitrains from the Teruel and Asturias basins can be distinguished from the extraction yield data. 相似文献