循环高压电脉冲作用下煤体微裂隙发育特征及其煤岩学控制

基于开放式循环高压电脉冲实验平台,针对肥煤、贫煤和无烟煤3种不同变质程度煤样,开展金属丝和含能材料2种能量加载方式下的煤样冲击致裂实验,通过光学显微镜分析循环冲击作用下煤中微裂隙发育的煤级与载荷响应特征,研究微裂隙扩展演化与显微组分之间的关系。结果发现:①增加循环冲击次数,微裂隙密度的增大趋势是非线性的,大致可划分为初期缓慢增加、中期快速增大、后期趋于稳定3个阶段,说明并非循环冲击次数越多致裂效果越好,而是存在一个最佳冲击次数。②金属丝加载方式下煤中微裂隙较含能材料加载下更为发育;整体上,肥煤的微裂隙发育程度高于贫煤,贫煤高于无烟煤,反映循环高压电脉冲在致裂效果上可能具有“双低效应”,即低变质程度煤加载低能量致裂效果可能更好。③微裂隙发育程度在显微组分之间具有差异性和侧重性,镜质组最发育,惰质组次之,壳质组最少,这是镜质组含量大(空间优势)、原位裂隙密度大(位置优势)、脆性较大(力学优势)综合作用的结果。④微裂隙在显微组分中的扩展演化轨迹可归纳为穿越显微组分、局限在显微组分内部、沿显微组分边界发育和形态呈斜列、渐进式张剪性扩展等主要特征。研究结论对进一步揭示循环高压电脉冲煤层致裂微观机制,明确工程实践目标煤层,优化作业工艺参数和提高作业效果具有重要的理论意义。      

贵州构皮滩地区裂隙系统及其对电站工程的影响研究

大坝、隧道等大型工程中的裂隙构造,由于关系到岩体的强度等工程安全问题,因此历来倍受关注。贵州乌江构皮滩电站坝区主要发育碳酸盐岩及少量碎屑岩,在其岩系中构造裂隙主要有NNW向、NWW向、NEE向和NE向,其中约80%已被方解石脉先后分四期充填愈合,大大降低了水的渗透,提高了岩石的强度;有少量裂隙没有被充填,或是充填以后又裂开,其中顺层滑动裂隙具一定的贯通性,工程上值得注意。      

潞安矿区煤储层裂隙及其与人工裂缝的关系

为了研究潞安矿区煤储层压裂人工裂缝与天然裂隙的关系,井下实测了矿区煤储层宏观裂隙,扫描电镜观测了煤储层显微裂隙;探讨了矿区含裂缝非均质煤岩破裂规律。对原位煤储层条件下人工裂缝沿天然裂隙扩展的最大水平主应力方向与天然裂隙走向夹角的临界值进行了计算。结果表明:矿区的漳村、司马、屯留、常村和五阳5个区块临界值分别为12.00°、9.22°、9.16°、8.56°和7.42°,当最大水平主应力方向与天然裂隙走向的夹角小于此临界角时,人工裂缝沿天然裂隙扩展,反之沿最大水平主应力方向扩展。据此,探讨了潞安矿区原位煤储层压裂裂缝沿天然裂隙扩展的3种模式。      

煤中的孔隙与裂隙

讨论了煤中孔隙、裂隙分布规律和影响因素。认为煤中孔隙、裂隙的发育总体上受变质程度的控制,煤相影响了煤的物质组成。     

不同初始瓦斯压力下煤体动力学特性及其劣化特征

为探究不同初始瓦斯压力下煤体动力学特性及其劣化规律,利用自主研发的含瓦斯煤岩动静组合加载试验系统对含瓦斯煤开展冲击压缩试验,结合CT扫描系统分析了含瓦斯煤内部裂隙的扩展演化规律,并基于不同初始瓦斯压力下冲击煤样内部裂隙率增量定量表征了其细观损伤程度,探讨了冲击荷载作用下含瓦斯煤宏观力学参量劣化规律。研究结果表明：（1）冲击荷载作用下含瓦斯煤动态应力-应变曲线无明显压密阶段,分为线弹性阶段、塑性硬化阶段和破坏阶段,并发现随初始瓦斯压力升高,冲击煤样峰值强度、峰值应变和弹性模量均出现弱化现象;（2）瓦斯加剧了煤体内部裂隙的扩展和贯通,并根据CT扫描结果发现,含瓦斯煤冲击破坏模式主要以劈裂和层裂破坏为主,随初始瓦斯压力升高,两种破坏模式越显著,煤体内部裂隙数量及其损伤程度逐渐增大,空间裂隙网络更为复杂;（3）基于细观层面定义了损伤变量,得其值随初始瓦斯压力升高呈现二次函数上升,对比冲击载荷作用下煤体动态强度与以裂隙率增量定义损伤程度所得理论强度,验证了细观层面煤体裂隙率增量定义损伤变量的合理性,建立了含瓦斯煤细观劣化与宏观参量损失的内在联系。研究成果丰富了含瓦斯煤动力学基础理论,为矿井煤岩瓦...     

含方解石脉石炭系灰岩单轴压缩的变形破裂特点

沉积岩形成后由于构造运动和热液运移而导致节理裂隙中晶体生长形成岩脉充填,方解石脉充填节理裂隙后与母岩形成整体,公路隧道及边坡工程中会经常遇到岩体中充填有大量的方解石脉。方解石脉与围岩之间的边界由于形成地质结构,所以对于岩体在应力作用下的力学响应具有重要作用,另外方解石脉的充填厚度也会显著影响到岩体的整体力学行为。本次研究从贵州省惠水至兴仁高速公路工程野外露头采集了含有不同厚度方解石脉的石炭纪石灰岩,考虑到不同厚度方解石脉充填以及区域长期降雨过程中水对岩石力学行为影响这两个重要因素,首先对天然以及饱和后的岩石切片开展了矿物组构的统计分析,然后在实验室制备了标准圆柱形岩石试样并开展了天然以及饱和后的单轴压缩力学实验。通过单轴压缩实验获得了试验过程的全应力-应变曲线,针对破裂后试样采用工业CT扫描及三维重构获得了岩石试样中的裂缝形态特点。经过对饱和以及天然状态下含不同厚度方解石岩脉灰岩的力学行为和裂缝分布的分析发现,由于方解石岩脉厚度和含水饱和度的增加,其单轴受压状态下整体塑性显著增加且强度明显降低,岩石饱和后矿物组构的变化以及方解石脉厚度的增加对其力学行为以及破裂模式有明显影响。另外随着方...     

煤储层裂隙形成机理及其研究意义

煤储层的微裂隙与内生裂隙是煤中流体压力与有效地应力相互作用过程中高压流体间 歇性集中释放所致。煤的化学成分，孔隙特征及流体生成特征决定煤中裂隙的发育特征，水平有效地应力决定主内生裂隙面的发育方向。煤中流体的释放受流体压力，地应力和裂隙残余变形的影响。     

焦家金矿床容矿裂隙特征及成生机制

着重研究构造作用下成矿裂隙特征和流体的运移通道、方式及成因机制,结果认为焦家金矿床差异的矿体矿化特征主要由不同裂隙导致形成,微构造裂隙之间没有截然分开的界线,常呈渐变接触关系。矿化裂隙成生主要有流体驱动显微构造裂隙扩展和构造剪张形成脉状裂隙两种方式。流体运移以真空泵式为主,渗流方式为辅,不同的裂隙成生机制和流体运移方式导致形成差异的矿化特征。     

沁水盆地南部煤储层显微裂隙发育的影响因素

为研究沁水盆地南部3号和15号煤储层显微裂隙的发育情况,借助扫描电镜显微裂隙分析、荧光显微镜显微裂隙统计、X射线衍射分析等手段,总结了地应力、煤岩显微组分、煤变质程度、煤中矿物质与显微裂隙发育的关系,探讨了影响煤储层显微裂隙发育主要因素。结果表明,该区煤储层显微裂隙较为发育,显微裂隙密度一般为7~59条/9 cm2,以C型和D型裂隙为主,扫描电镜下常见张性裂隙、剪性裂隙,对煤储层渗透性贡献较大,内生裂隙较少见。显微裂隙通常发育于镜质组中,裂隙密度随变质程度的升高表现出降低的趋势,煤中矿物的充填作用对于显微裂隙的发育影响较大,对煤样渗透性造成了直接破坏作用,地应力场的方向和大小控制着外生显微裂隙的开合程度,进而对煤储层的渗透性产生影响。因此认为,地应力和煤中矿物是影响该区煤储层显微裂隙发育的主要因素。      

中国煤储层渗透率主控因素和煤层气开发对策

我国煤储层渗透率比美国煤储层渗透率低1~2个数量级,低渗透率是制约我国煤层气勘探开发的主要因素之一,本文系统分析了我国煤储层渗透率的主控因素。研究表明,煤储层的渗透率主要受煤体结构、宏观裂隙以及割理/裂隙系统充填状况和现今地应力等因素的控制,适度构造变形产生的碎裂煤中因宏观裂隙发育导致其渗透率高于原生结构煤的渗透率,但强烈构造变形形成的碎粒煤和糜棱煤则使渗透率降低;割理/裂隙系统矿物充填和高应力不利于渗透率保存。在不同地区,控制煤储层渗透率的关键因素不同,针对性对策是煤层气开发的关键:针对复杂煤体结构,在压裂井层优选时要在煤体结构测井解释的基础上考虑避开糜棱煤;针对我国华北地区石炭—二叠系煤层割理/裂隙普遍以方解石充填为主的煤储层低渗透成因,建议探索和开发酸化压裂一体化储层增透技术;针对高应力和地应力类型在垂向上的转换,在压前搞清应力强度和类型的基础上,控制水力压裂隙高度以避免沟通煤层围岩含水层;针对煤储层的应力敏感性和高应力状态,建议采用逐级降压制度,以提高单井的累计产气量。     

华南湘桂粤地区煤中热液脉体的岩石学研究

煤中高含脉率脉体的出现，是煤热液变质作用的重要依据之一。本文详细讨论了湘桂粤地区早奥陶世、早石炭世、晚二叠世和晚三叠世煤中热液脉体的种类、岩石学特征及其与煤变质程度的关系。无论什么时代的无烟煤，随着其变质程度升高，煤中脉体的种类增多，矿物成分变得复杂，较高温热水矿物出现。     

煤中剪切指向标志的类型讨论

通过与岩石中的剪切指向标志对比,初步研究了煤中的剪切指向标志。发现了如羽状脉体等特殊的指向标志。煤中剪切指向标志研究,是岩层构造运动学分析的主要内容,可判别局部剪应力方向,进而为确定应力场提供依据。      

Germanium speciation in lignite from a germanium-bearing deposit in Primorye

We studied a number of chemical characteristics in the coals of the Spetsugli germanium-bearing area of the Pavlovskoe coalfield in southern Primorye. It was found that the coals show variable contents of ash, extractable organic matter (OM), and germanium. No less than 60% germanium in the coals are bound to mobile OM, including 25–60% in complex compounds of humic acids and 8–39% in the low-molecular-weight fraction of OM not precipitated by acids. It was shown that germanium can be partly accumulated in coals as organic compounds owing to the dissolution of the mineral forms of germanium by humic acids.     

试论等变质煤镜质体性质差异之普遍性

选择了不同地区和时代的不同变质程度的5个系列的煤样,对分离富集的镜质体主要特征进行了比较研究。研究发现:按海相和陆相划分,属同一相的不同时代的等变质煤的镜质体性质仍有差异,有些甚至相当明显。这表明,等变质煤镜质体性质存在的差异具有普遍性,并且其成因不止有煤相一个因素。      

热-力作用原煤变形特征与力学性质演化试验研究

开展原煤在热-力作用下煤热膨胀与吸附瓦斯解吸研究对于深入理解深部煤岩失稳破坏机制有重要意义。通过对四川白皎矿和徐州张双楼矿的原煤施加不同温度-应力条件,获取煤的热变形、解吸气体运移以及煤的力学性质的热响应。试验结果表明:白皎煤在低于35℃条件下表现为膨胀变形;在高于35℃恒温环境下,煤体变形表现为先膨胀后收缩趋势。张双楼煤在低于60℃条件下表现为先膨胀后会出现收缩;在高于60℃恒温环境下,煤样趋向整体膨胀。其结果说明,煤岩在热环境中的变形行为取决于煤基质的热膨胀与解吸收缩之间的竞争结果。煤吸热升温后孔隙中解吸气体数量增多,煤样在受载压缩变形过程中显现出复杂解吸气体排放特征,包括煤中原生孔隙裂隙压缩闭合排出气体,煤体内不均匀变形导致气体流动,煤体开裂导致气体回流。力学测试结果表明,煤样的单轴抗压强度以及弹性模量随着环境温度上升均表现出下降趋势。其结果为深入理解深部煤层在热-力耦合下渗透率与强度变化机制提供试验依据。     

煤中金的研究现状及其展望

煤中金因其可异常聚集而日益受到重视,其潜在的经济价值又为该贵金属来源提供了新的途径.详细分析了前人对煤中金研究的相关文献,就煤中金的丰度、分布、成因及其工业前景进行了较全面的阐述,并重点讨论了煤中金异常聚集的地质机制,认为存在河流或大气降尘带入泥炭沼泽、同沉积过程中有机物质吸附富集和后生成因等3种主要的富集机制,且当煤被灰化后灰分中金会进一步富集,其富集度可以高出原煤的几倍,甚至几十倍,达到工业利用价值.深入揭示金在煤炭加工利用过程中的迁移、聚集的机制,发展煤中金的提取技术是很有必要的、前瞻性的工作,也是进行煤中伴生金地质经济评价的基础.     

黔西南高砷煤的分布及地球化学特征研究

根据野外地质特征结合中子活化成分分析结果,探讨了黔西南高砷煤的分布特征、影响因素和某些地球化学特征。高砷煤严格受构造（褶皱和断层）、地层（二叠系龙潭组）、沉积相（海陆交互相）的控制,分布于平行北斜长轴的断层两侧,愈靠近断层面砷的含量愈高。砷在煤中的分布极不均匀,即使同一煤层变化也极大。在时空关系与元素组合上高砷煤与区内卡林型金矿密切相关。     

Delineation of the distinctive nature of tertiary coal beds

Floral character in mires has changed progressively through time. In the Carboniferous, pteridophytes, sphenophytes and lycophytes were dominant but by the Permian gymnosperms were an important component of mire flora. During the early Mesozoic gymnosperms remained the characteristic mire vegetation, together with pteridophytes, and conifers became dominant during the Jurassic. Cretaceous and Paleocene vegetation are similar, with taxodiaceous flora being important in mire vegetation. From the Eocene onwards, however, angiosperms were increasingly dominant in mire communities and in the Miocene herbaceous vegetation began to play a significant role. Together with these changes in floral character at least three aspects of coal character also appear to vary sequentially with time and are distinctive in the Tertiary: (1) proportions and thickness of vitrain banding, (2) coal bed thickness and (3) proportions of carbonised material. A compilation has been made of data from the coal literature comparing older coals with those of the Tertiary, in order to give a perspective in which to examine Tertiary coals. It was found that only Tertiary coals contain significant proportions of coal devoid of vitrain bands. In addition, Tertiary coals are the thickest recorded coal beds and generally contain low percentages of carbonised material (many less than 5%) as compared to older coals. It is interesting to note that Paleocene coal beds are similar to Cretaceous coals in that they tend to be thinner and contain higher proportions of carbonised material than do younger Tertiary coals.The absence of vitrain bands in some Tertiary coal beds is thought to result from the floras dominated by angiosperms, which are relatively easily degraded as compared to gymnosperms. The thickness of Tertiary coals may be related to an increase in biomass production from the Carboniferous through to the Tertiary, as plants made less investment in producing lignin, an energy-intensive process. In addition, with less lignin in plants, easier degradation of biomass may have facilitated nutrient recycling which, in turn, led to greater biomass production. Increased biomass production may have also ‘diluted’ the carbonised material present in some Tertiary peats, leading to lower proportions in the coal. Another possible cause of decreased carbonised components in Tertiary coal is that decreasing lignin content resulted in decreased charring during fires, as lignin is particularly prone to charring. A third possibility is that the carbonised component of peat may be concentrated during coalification so that Tertiary coals, generally of lower rank than Mesozoic or Paleozoic coals, contain a smaller fraction of carbonised plant material. It is not at present clear which of these mechanisms may have affected carbonised material in peat and coal but it is clear that lignin type and content has had an important role in determining peat and coal character since the Paleozoic.     

Geological and geochemical characteristics of high arsenic coals from endemic arsenosis areas in southwestern Guizhou Province,China

Southwest Guizhou Province is one of the most important areas of disseminated, sediment-hosted-type Au deposits in China and is an important area of coal production. The chemistry of most of the coals in SW Guizhou is similar to those in other parts of China. Their As content is near the Chinese coal average, but some local, small coal mines contain high As coals. The highest As content is up to 3.5 wt.% in the coal. The use of high As coals has caused in excess of 3000 cases of As poisoning in several villages. The high As coals are in the Longtan formation, which is an alternating marine facies and terrestrial facies. The coals are distributed on both sides of faults that parallel the regional anticlinal axis. The As content of coal is higher closer to the fault plane. The As content of coal changes greatly in different coal beds and different locations of the same bed. Geological structures such as anticlines, faults and sedimentary strata control the distribution of high As coals. Small Au deposits as well as Sb, Hg, and Th mineralization, are found near the high As coals. Although some As-bearing minerals such as pyrite, arsenopyrite, realgar (?), As-bearing sulfate, As-bearing clays, and phosphate are found in the high As coals, their contents cannot account for the abundance of As in some coals. Analysis of the coal indicates that As mainly exists in the form of As⁵⁺ and As³⁺, perhaps, combined with organic compounds. The occurrence of such exceptionally high As contents in coal and the fact that the As is dominantly organically associated are unique observations.     

鲁西南地区石炭纪—二叠纪含煤岩系层序地层及聚煤特征

根据钻井、测井和地质等资料,对鲁西南地区石炭纪—二叠纪含煤岩系进行了层序地层学与聚煤作用研究。识别出以区域不整合面、古土壤层底面、海侵方向转换面、下切谷砂体底面为代表的4种类型的层序界面;划分出本溪组、太原组、山西组和下石盒子组中的4个三级层序,从下到上依次为SⅢ1、SⅢ2、SⅢ3及SⅢ4。通过对比研究不同层序的含煤性及煤层的发育特征后认为,形成于分流间湾沼泽环境的SⅢ3煤层发育最好,形成于潟湖与沼泽环境的SⅢ1及SⅢ2煤层发育次之,SⅢ4没有煤层发育。在同一个层序内部,泥炭聚集速率与可容空间增加速率之间的平衡状态决定了煤层的厚度,这种平衡状态保持较长时间是煤层形成的基本条件,而与泥炭聚集有关的可容空间的持续增加需要基准面的不断抬升,因此,发育较好的煤层最可能形成于海侵体系域末期,如SⅢ3的TST末期的3号煤层。