河南胡襄煤田煤层赋存特征及控气因素

以河南胡襄煤田为研究区,通过定性分析和定量研究,探讨了煤层厚度、煤层埋深、上覆基岩厚度、地质构造、顶底板岩性以及变质程度等因素对煤层气富集的控制作用.通过数理统计方法,得出了煤层厚度、埋深、上覆基岩厚度与煤层含气量的回归方程,并进行了显著性检验.研究结果表明,随着煤层厚度的增加,含气量有着增大的趋势,两者之间具有线性正相关关系;随着埋深和上覆基岩厚度的增加,含气量都有着先快速增大而后缓慢增大的趋势,且具有对数正相关关系;煤变质程度是二1煤层和二2煤层含气量变化的影响因素之一,且含气量随Ro,max的增加而增大;次级褶曲向斜翼部和背斜轴部富气,且向抬升区域运移;断层或煤层露头线附近,含气量较小;断层的上升盘含气量明显小于下降盘;断层尖灭端附近,含气量大;煤层顶底板岩性对含气量有一定的影响.     

沁南煤层气合层排采有利开发地质条件

针对沁水盆地南部山西组3#与太原组15#煤层煤层气合层排采"整体产能低"及"区域性差异大"的产能特征,探索适合合层排采的有利开发地质条件.以沁水盆地南部22口合层排采煤层气井的产气、产水资料,试井储层压力、试井渗透率、含气量等测试数据为依据,采用地质研究与探采测试数据分析相结合的方法,分析了不同地质因素对合层排采井产能特征的控制作用,提出了适合沁南3#与15#煤层合层排采的有利开发地质条件的参数指标.结果表明:平均埋深为500~650m;平均含气量大于14m3/t;储层压力梯度差小于0.08 MPa/hm;渗透率较高且差值不超过1mD;3#煤层的临界解吸压力高于15#煤层,且差值小于0.9MPa,满足合层排采的地质条件要求,可为今后进行规模性开发提供借鉴.     

煤层气生成及含气量控制因素

利用EASY%Ro数值模拟法,对峰峰东部矿区2号煤煤层热演化史进行模拟及恢复,探讨了峰峰东部矿区2号煤煤层气的生成和演化特点,认为峰峰东部矿区受构造运动及岩浆活动的影响,经历二次生气阶段,早期以区域深成变质作用为主,煤中有机质在深成变质作用下发生一次生气;晚期受岩浆活动的影响,促使该区的煤层进一步变质及煤层气第二次生成。在此基础上分析了研究区含气性及含气性的主要控制因素,包括煤储层顶底板岩性、分布特征、地质构造、岩浆侵入及水文地质条件等引起本区煤层甲烷含量在平面及剖面上分布的不均一性。     

白额地区2~#煤层气藏成藏控制因素分析

在分析白额地区2^#煤储层空间发育特征、储层物性特征、含气量分布特征及区域构造背景的基础上,对煤层气成藏控制因素进行分析。结果表明：构造演化史直接控制着煤储层埋藏史及生烃史,是煤层气成藏主控因素;地下水水动力特征和围岩封闭特征决定了煤层气藏的保存条件,是煤层气成藏的关键;综合以上特征,可以得出2#煤煤层气藏为单斜-水动力封堵型煤层气藏。     

沁水盆地高家庄区块高煤阶煤吸附特征及控制因素

基于煤储层对甲烷吸附特征在煤层气勘探开发中的重要性,采用等温吸附试验,对高家庄区块高煤价煤储层吸附特征进行研究,并分析其控制因素。结果表明:高家庄区块主煤储层兰氏体积大于26cm3/g,兰氏压力中等,具有较强的煤层甲烷吸附和储集能力;其中,15#煤储层对甲烷的吸附能力要明显好于山西组3#煤储层,但吸附能力区域差异较大;煤阶和煤岩有机显微组分是研究区煤储层甲烷吸附特征的重要控制因素,水分和灰分在一定程度上降低了煤储层吸附能力。     

陆相盆地低煤级煤储层特征研究—以准噶尔、吐哈盆地为例

研究了准噶尔、吐哈盆地低煤级煤储层的特征,结果表明：该储层几何形态复杂,且受成煤环境的控制,表现出显著的规律性变化。煤体形态可归纳为与成煤环境对应的4种类型,其中形成于湖成三角洲的朵状、舌状煤体成藏规模最大,浅部煤储层以含气量低、甲烷浓度低、含气饱和度中等、含气强度大为特征;但在构造相对简单的盆缘斜坡深部具有很好的勘探开发潜力,煤储层孔容及比表面积都很大且变化范围也大;中值孔径、孔隙率的变化特征与孔容一致,预示了低煤级煤储层较高的基岩渗透率,兰氏体积和兰氏压力都显著低于中、高煤级煤储层,煤储层达到饱和的机率更大,更容易解吸。古构造应力场控制着煤储层割理裂隙系统的发育程度和分布规律,现代构造应力场特征影响煤储层割理裂隙系统的开合程度,盆缘斜坡多为高渗区。     

华北地区煤层含气性影响因素探讨

煤层含气性是评价煤层气勘探开发前景的决定性因素之一,影响煤层含气性的因素很多,其中较为重要的因素有煤层上覆有效地层厚度、煤的变质程度、断裂构造、盖层条件及煤层厚度等.对此进行了分析探讨,认为:影响煤层含气性的主要地质因素为煤层上覆有效地层厚度和煤的变质程度,次要因素为断裂构造、盖层条件及煤层厚度.     

华北地区煤层含气性影响因素探讨

煤层含气性是评价煤层气勘探开发前景的决定性因素之一,影响煤层含气性的因素很多,其中较为重要的因素有煤层上覆有效地层厚度、煤的变质程度、断裂构造、盖层条件及煤层厚度等.对此进行了分析探讨,认为影响煤层含气性的主要地质因素为煤层上覆有效地层厚度和煤的变质程度,次要因素为断裂构造、盖层条件及煤层厚度.     

煤层含气量预测的BP神经网络模型与应用

为了对煤层含气量进行定量预测,采用BP神经网络预测方法,建立了煤层含气量预测的BP神经网络模型．以沁水盆地南部主采煤层为对象,分析得出了影响沁水盆地南部煤层含气量分布的主要控制因素有煤层有效埋藏深度、煤变质程度和煤岩、煤质特征等,选择了煤层有效埋藏深度、水分与灰分以及镜质组最大反射率3参数作为BP神经网络模型的基本特征量,建立了煤层含气量与这些因素之间的相关关系和BP神经网络预测模型,对煤层含气量进行预测分析．结果表明：BP神经网络模型具有极强的非线性逼近能力,能真实反映煤层含气量与主控因素之间的非线性关系,预测结果与实测值之间误差小,相对误差小于10%,预测效果明显地优于基于朗格缪尔方程的煤层含气量预测模型．     

贵州省织金、纳雍地区煤储层物性特征研究

为了探讨织金、纳雍地区煤层气的勘探开发潜力,运用各种测试手段从孔、裂隙系统角度研究了该区煤储层物性特征,分析了煤储层的聚气能力、渗流能力及其控制因素.研究后认为该区煤变质程度高,煤储层吸附能力强,对煤层气的吸附聚集较为有利;而煤储层渗流能力低,仅局部地区存在高渗条件,不利于煤层气的产出;煤储层物性特征受控于该区复杂的构造条件,前燕山期的深成变质作用使得煤岩吸附能力增强,渗流能力下降,而燕山期强烈的构造运动使得断裂带附近的煤储层吸附能力和渗流能力整体增大,改善了局部地区煤储层物性特征.研究结果表明：织金、纳雍地区煤储层孔隙中以吸附孔为主,吸附孔隙百分比为50.61%～89.71%,吸附能力较强;而煤储层渗流孔隙百分比仅为21.14%,且煤岩显微裂隙密度普遍低于100条/9cm2,裂隙连通性较差,煤储层的渗透率相对较低;强烈的构造活动产生了大量的断层,地下的岩浆热液通过断层向上侵入,使得局部地区煤的变质程度迅速增加,同时产生大量的孔裂隙,改善了断层发育区附近煤储层的孔渗条件,后期的矿化作用充填了部分孔裂隙,一定程度上控制了煤储层物性,不利于后期的煤层气开发.     

Reservoir reconstruction technologies for coalbed methane recovery in deep and multiple seams

Multiple coal seams widely develop in the deep Chinese coal-bearing strata. Ground in situ stress and coal seam gas pressure increase continuously with the increase of the mining depth, and coal and gas outburst disasters become increasingly severe. When the coal is very deep, the gas content and pressure will elevate and thus coal seams tends to outburst-prone seams. The safety and economics of exploited firstmined coal seams are tremendously restricted. Meanwhile, the multiple seams occurrence conditions resulted in different methane pressure systems in the coal-bearing strata, which made the reservoir reconstruction of coal difficult. Given the characteristics of low saturation, low permeability, strong anisotropy and soft coal of Chinese coal seams, a single hydraulic fracturing surface well for reservoir reconstruction to pre-drain the coalbed methane(CBM) of multiple seams concurrently under the different gas pressure systems has not yet gained any breakthroughs. Based on analyses of the main features of deep CBM reservoirs in China, current gas control methods and the existing challenges in deep and multiple seams, we proposed a new technology for deep CBM reservoir reconstruction to realize simultaneous high-efficiency coal mining and gas extraction. In particular, we determined the first-mined seam according to the principles of effectiveness and economics, and used hydraulic fracturing surface well to reconstruct the first-mined seam which enlarges the selection range of the first-mined seam. During the process of mining first-mined seam, adjacent coal seams could be reconstructed under the mining effect which promoted high-efficiency pressure relief gas extraction by using spatial and comprehensive gas drainage methods(combination of underground and ground CBM extraction methods). A typical integrated reservoir reconstruction technology, ‘‘One well for triple use", was detailed introduced and successfully applied in the Luling coal mine. The application showed that the proposed technology could effectively promote coal mining safety and simultaneously high-efficiency gas extraction.     

乡宁矿区煤储层地质特征研究

煤层气富集成藏受煤储层地质特征的制约。通过对大量实验测试数据的分析与对比,研究了乡宁矿区煤层气成藏基础地质特征,主要包括煤储层发育特征、煤岩学特征、煤化学与工艺特征及煤级与煤相特征等。结果表明,本区主要煤层煤空间展布稳定、累计厚度大、煤质好、热演化程度高,具备煤层气成藏的基础条件。     

精查勘探期间井田煤与瓦斯突出危险性预测

本文通过精查勘探期间测定煤层瓦斯压力、瓦斯含量、瓦斯突出指标及瓦斯地质条件的分析，对韩庄井田３号、１５号煤层突出危险性进行了预测，并为生产设计部门提供了科学依据．     

新集一矿孔隙结构特征研究

为进一步了解新集一矿煤层孔隙结构特征,通过压汞法和低温氮等温吸附法实验手段对新集一矿主采煤层孔隙发育特征进行研究。发现新集一矿主采煤层孔隙度较比两淮矿区其他地区高。其中以8煤层8XJ5号样为代表孔隙分布以小孔最发育,大孔较发育,中孔少见为特征和以13-1煤层13XJ10号样为代表孔隙分布以小孔最发育为特征的基质孔,孔隙之间的连通差,不利于瓦斯的抽排;以11-2煤层11XJ3号样和6-1煤层6XJ15号样为代表中孔发育,孔隙以裂隙性为主,孔隙之间的连通较好,有利于瓦斯的运移。     

沁水盆地南部煤层气藏特征

以油气、煤田和煤层气勘探阶段积累的资料为基础,系统探讨了沁南煤层气藏的特征.通过对气藏静态特征(包括煤层空间几何形态、煤层气成分和含量、储层物性、吸附特征、储层压力及封闭条件)和动态过程(包括煤层气形成、运移和聚集)的分析,指出晚古生代的煤层在经历了印支期和燕山期两次煤化作用生成的煤层气,在喜马拉雅期遭受了严重的调整与改造后逐渐形成现今的沁南煤层气藏.直接控制该煤层气藏中煤层气富集程度的因素为顶底板与边界断层.目前的高产煤层气井基本上都位于地下水滞流区.     

Evaluation of gas production from multiple coal seams: A simulation study and economics

Gas production from multiple coal seams has become common practice in many coal basins around the world. Although gas production rates are typically enhanced, the economic viability of such practice is not well studied. In order to investigate the technical and economic feasibility of multiple coal seams production, reservoir simulation integrated with economics modelling was performed to study the effect of important reservoir properties of the secondary coal seam on production and economic performance using both vertical and horizontal wells. The results demonstrated that multiple seam gas production of using both vertical and horizontal wells have competitive advantage over single layer production under most scenarios. Gas content and permeability of the secondary coal seam are the most important reservoir properties that have impact on the economic feasibility of multiple seam gas production. The comparison of vertical well and horizontal well performance showed that horizontal well is more economically attractive for both single well and gas field. Moreover, wellhead price is the most sensitive to the economic performance, followed by operating costs and government subsidy. Although the results of reservoir simulation combined with economic analysis are subject to assumptions, multiple seam gas production is more likely to maintain profitability compared with single layer production.     

煤层群煤与瓦斯安全高效共采体系及应用

提出了高瓦斯煤层群煤与瓦斯安全高效共采的概念：在煤层群开采条件下，首先开采瓦斯含量低、无突出危险的首采煤层，利用其采动影响使处在其上部和下部的煤层卸压，煤层透气性成百倍地增加，从而形成高效的瓦斯抽采条件．同时进行的卸压瓦斯高效抽采既解决了由卸压煤层向首采煤层涌出瓦斯问题，保障首采煤层实现安全高效开采，又大幅度地降低了卸压煤层的瓦斯含量，消除了煤与瓦斯突出危险性，为在卸压煤层内实施快速掘进与高效采煤方法提供了安全保障，从而实现了瓦斯与煤炭两种资源的安全高效共采．文中介绍了针对不同卸压瓦斯流动特点的近程、中程和远程卸压瓦斯抽采方法及工程应用实践，最后对高瓦斯煤层群煤与瓦斯安全高效共采体系的应用前景进行了分析．     

应用XPS研究镜煤中有机硫的存在形态

应用 XPS方法研究了鄂尔多斯盆地西北缘乌达矿区 9煤层、1 2煤层和 1 5煤层手选镜煤的有机硫赋存状态 .结果表明 ,煤中有机硫的存在形式是多样的 ,这主要取决于成煤母质、沉积环境和泥炭堆积后的成岩变化 .在泥炭堆积过程中 ,由于菌类和藻类低等生源的大量输入 ,是导致9煤层有机硫以噻吩型 ( 5 0 .67% )为主的主要原因 ;从 9煤层 ( Ro,ran=0 .96% )到 1 5煤层 ( Ro,ran=1 .0 9% )随着煤级增高 ,有机硫表现出以噻吩型为主的趋势 ;1 5煤层含有较高的硫砜型硫( 8.42 % ) ,这可能与该煤层中壳质组含量稍高 (φ(壳质组 ) =1 .6% )有关     

岱庄煤矿影响煤中微量元素的地质因素

微量元素具有一些特殊的地球化学性能,如化学性质稳定、均一化程度高等特点。岱庄煤矿主采煤层共四层（3上、3下、16、17煤层）,微量元素含量从3上煤层到17煤层逐渐增大。通过对岱庄煤矿煤中微量元素成煤植物、陆源区母岩性质、沉积环境以及其它一些影响因素进行分析,总结岱庄煤矿煤中微量元素的分布和富集成因,能够更加准确掌握不同煤层中微量元素的赋存规律及赋存状态。     

A numerical investigation of gas flow behavior in two-layered coal seams considering interlayer interference and heterogeneity

Multiple-seam gas coproduction is a technology with potential to achieve economic targets. Physical experiments could replicate gas flow dynamics in two seams. In this study, numerical simulation was conducted based on physical experiments. Through calibration, the simulated results agreed with the experimental results. Three findings were obtained. First, the pressure distribution intrinsically depends on the depressurization effectiveness in each coal seam. The gas pressure difference and interval distance influence the pressure distribution by inhibiting depressurization in the top seams and bottom seams, respectively. Second, the production contribution shows a logarithmic relationship with the permeability ratio. The range of the production contribution difference grows from 11.24% to 99.99% when the permeability ratio increases 50 times. By comparison, reservoir pressure has a limited influence, with a maximum of 13.64%. Third, the interlayer interference of the top seams and bottom seams can be intensified by the reservoir pressure difference and the interval distance, respectively. The proposed model has been calibrated and verified and can be directly applied to engineering, serving as a reference for reservoir combination optimization. In summary, coal seams with a permeability ratio within 10, reservoir pressure difference within 1.50 MPa, and interval distances within 50 m are recommended to coproduce together.