【作者】 蔚远江；

【导师】 杨起；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2003， 博士

【摘要】 本文在国内外煤层气储层地质研究现状及进展、准噶尔盆地侏罗系煤储层地质背景和沉积特征调研基础上，对低煤级煤储层特征及其富气成藏机制进行了初步研究。首先，根据下侏罗统八道湾组（J₁b）和中侏罗统西山窑组（J₂x）煤储层发育、煤岩、煤质、煤级、煤类、煤相地质特征论述了本区低煤级煤层气生成的物质基础。通过矿井现场、镜下观察统计等常规手段，采用多种先进仪器和测试技术展开对煤储层的裂隙系统与孔隙系统发育特征、储渗性能、吸附特性及煤储层围岩物性特征的多层次、多手段分析，并综合室内外观测及前人成果，提出了煤储层裂隙与孔隙系统的划分标准与识别特征，分别从宏微观尺度、定性与定量层次对裂隙与孔隙系统特征及其与煤储层储渗性能关系的研究。 在本区瓦斯分带、已知煤层气显示及其组分研究基础上，探讨了低煤级煤层气的生成机制，指出生成的煤层气应包括褐煤阶段的原生生物甲烷气、长焰煤—气肥煤阶段的热成因甲烷气和煤层埋藏阶段的次生生物甲烷气三种成因甲烷气体；进而论述了煤储层含气饱和度、临界解吸压力、临储压力比、地解压差等甲烷解吸特征，实测与理论含气量、煤层气资源量与资源丰度等煤储层含气性特征。 分别简述了准噶尔盆地1000m及2000m深度今古地温场、1600m以浅的煤系地层压力场、侏罗纪至今地应力场及煤系地层水势与气势分布的今古流体势场基本特征，进而对这“四场”特征及其互动关系与煤储层物性、可采性及煤层气聚集的关系进行了探讨。从构造背景、构造演化及构造类型几方面论述了本区构造作用的控气特征。根据沉积作用对聚煤作用（煤储层的厚度、分布及含煤性特征），对煤储层的形成与展布、煤岩组成、有机相和煤相、顶底板盖层类型与封盖性能的控制和影响，讨论了沉积作用的控气特征。从水文地质条件对煤层气储集性与可采性的影响论述了本区水文地质的控气特征，指出本区存在水压封闭气藏的可能性较小。在深入讨论本区煤储层的控气地质因素后，进一步阐明沉积埋藏史、构造演化史、煤化作用史的“三史”配置合理与否是影响煤储层富气与高产的主控因素。 采用定性与定量结合、层位与区块结合的方法分别对J₁b、J₂x煤储层在盆内各区块进行了定性与定量综合评价，定性可采性评价包括煤岩参数、储层条件及储集特性参数、物性参数三大类各参数的单项评价及综合评价，定量可采性评价采用多层次模糊综合评判法进行，指出八道湾组为中等储层、西山窑纽为好～中等储层；西山窑组煤储层性质总体要好于八道湾组。并重点通过该区煤储层物性特征研究，从孔隙结构、渗透率、等温吸附曲线类型等角度深入探讨了煤储层物性与煤层气可采性的关系。 在准噶尔盆地煤层气成藏有利条件研究的基础上，初步预测本区煤储层成藏最有利的层系是侏罗系西山窑组，J₁b煤储层在南缘东部为有利区、准东为较有利区；J₂x煤储层在南缘东部、准东为有利区，在南缘西部、西北缘为较有利区。有利区块为准南含气带的乌鲁木齐矿区、玛纳斯一带，准东的丘河—帐篷沟区；较有利区块是准南含气带的阜康矿区、巴音沟，准东含气带的北山煤窑—将军庙、滴水泉—五彩湾老君庙及三塘湖—巴里坤，准西北含气带的夏子街区及和什托洛盖地区。最后，对准噶尔南部乌鲁木齐西山—老君庙、阜康—白杨河—大黄山、准东滴水泉—大井等煤层气有利成藏区块进行了简单分述。更多还原

【Abstract】 On the basis of surveying on research actuality and advance of coalbed methane reservoirs geology, regional geological background and sedimentary characteristic of Jurassic coal reservoirs, this dissertation proceeded integrative study on low-rank coal reservoirs and preliminary probing into its coalbed methane pool forming mechanism in Zhungaer basin, northwest China.First of all, the substance foundation of low-rank coal CBM generation in the basin has been discussed according to the development of coal reservoir, coal petrography, coal properties, coal rank, coal genera,coal facies feature of lower Jurassic Badaowan formation(Jlb) and middle Jurassic Xishanyao formation (J2x).Multi-hierarchical, multimeans, Comprehensive and deepened research on the macrofractures, microfractures system and pores system features, capacity of CBM storage and osmosis, adsorption characteristic, as well as physical properties of surrounding rocks of coal reservoirs have been made. Furthermore, classifying standard and identifying characteristics for fractures-pores system of low coal rank coal reservoirs in Zhungaer basin has been put forward as well. In this process, some routine instrument are used, such as viewing coal mine scene and hand specimen, observing polished section and surface which are made from lump coal and powder coal samples, observing and image analyses under the common microscope’s transmitted light, reflection light and fluorescence. Advanced instrument and testing techniques including adopting mercury injection apparatus, specific surface analyses apparatus, porosity-permeability measurement apparatus, isothermal adsorption instrument and drill core flow experiment system, etc., are also adopted.On the basis of study on gas zoning, known CBM show and its component, generating mechanism of low coal rank CBM are discussed. The author pointed out that generated CBM should consist of primary biogenic methane gas in lignite stage, thermogenic methane gas in long-flame coal to gas/fat coal stage, and deuterogenic biogenic methane gas in coal seam imbedded stage. Then I discussed methane desorption properties including CBM-bearing saturation, critical desorption pressure, the ratio between critical desorption pressure and original coal reservoirs pressure and difference of terra decompression; CBM-bearing characteristics of coal seams including measured/academic CBM-bearing content, coalbed methane resources content and CBM resources abundance, etc.The author respectively gave a brief account of the basic characteristics of ancient and today’s geothermic field at 1000m and 2000m depth, coal measure strata pressure field at the depth less than 1600m, structural stress field from Jurassic to present, and ancient and today’s fluid potential field (that is water potential and gas potential distributing in coal measure strata). Then the relationship between these properties and its reaction relations each other among the " four fields" and physical properties of coal reservoirs, recoverability as well as CBM accumulation were discussed.Tectonic controls of coalbed methane in Zhungaer basin were dissertated from the several aspects, which are tectonic background, tectonic evolution and structural types.Sedimentary control of coalbed methane in this region were expounded according to the control and influence of sedimentation on coal gathering action (thickness of coal reservoirs, distributing and coal-bearing characteristics), on forming and distributing, maceral, organic facies and coalfacies, cap formation types and their sealing capability of adjoining rock. Hydrogeological control of coalbed methane in Zhungaer basins were also simply discussed from the influence both hydrogeological conditions on CBM accumulation; CBM diffusion and seepage flow in multiphase medium coal. It was indicated that the feasibility of occurring CBM pool which was sealing off by hydraulic pressure maybe very small.Qualitative and quantitative recoverability comprehensive assessment of every Jib and J2X coal reservoi更多还原