许疃矿主采煤层残余瓦斯重分布的地质控因研究

发布时间：2018-03-10 23:53

本文选题：许疃矿　切入点：煤储层物性　出处：《中国矿业大学》2017年硕士论文　论文类型：学位论文

【摘要】：本文以许疃煤矿为研究区,总结分析了许疃矿构造发育特征以及瓦斯赋存特征;并以3_2煤层为主要研究对象,通过对研究区煤岩进行压汞、等温吸附、光学显微镜观测和渗透率实验,探讨了研究区的煤储层物性特征和渗透性发育特征;对3_2煤层瓦斯赋存特征进行分析以及探讨各类地质条件对原位瓦斯赋存的影响;通过对33采区中3_2煤层抽采后的残余瓦斯进行归纳总结,得出残余瓦斯重分布特征,探讨了残余瓦斯重分布的控制因素。分析认为研究区孔径结构以微孔为主,过渡孔次之,中孔和大孔发育较差;由于构造煤较为发育,使得研究区煤体孔径结构和孔隙形态差异较大;煤岩裂隙密度平均为344条/cm~2,长度和宽度平均为2173μm和27.3μm,裂隙被填充的裂隙仅占6.3%;研究区煤岩吸附体积平均为9.9306 cm~3/g,吸附压力平均为1.404MPa;研究区煤岩渗透率与有效应力呈负指数相关,与瓦斯压力呈正相关。根据对原煤瓦斯赋存条件进行分析,煤层埋深为原煤瓦斯赋存主要控制因素。对研究区进行构造定量综合评价,构造综合复杂指数值最大值集中在F5断层周围,且F5断层周围原煤瓦斯含量降低;研究区顶底板岩性基本全区为透气性差的泥岩,有利于原煤瓦斯的赋存;瓦斯含量与煤层厚度具有较好的相关性。研究表明,研究区残余瓦斯重分布特征受到构造,煤层埋深和煤厚等地质条件控制。研究区断层较为发育,以小断层最为发育,残余瓦斯含量受到构造的影响,主要是小断层发育有利于残余瓦斯的赋存;煤层埋深越深,抽采前后瓦斯含量差值越大,能够有效的降低残余瓦斯含量;煤厚越厚,瓦斯含量差值越大;井下活动区域以及巷道附近残余瓦斯含量和残余瓦斯压力低,不利于残余瓦斯的赋存。抽采前后对瓦斯成分有影响,抽采后瓦斯成分中CO_2比例降低,N_2比例增高。
[Abstract]:Taking Xutuan Coal Mine as the research area, this paper summarizes and analyzes the structural development characteristics and gas occurrence characteristics of Xutuan Coal Mine, and takes 3s _ 2 coal seam as the main research object, through mercury injection, isothermal adsorption of coal and rock in the study area. The physical and permeability characteristics of coal reservoir in the study area are discussed by optical microscope observation and permeability experiment, and the gas occurrence characteristics of coal seam 3s _ 2 are analyzed, and the influence of various geological conditions on in-situ gas storage is discussed. Based on the summary of residual gas after mining in coal seam 3# 2 in 33 mining area, the characteristics of residual gas redistribution are obtained, and the controlling factors of residual gas redistribution are discussed. It is considered that the pore size structure in the study area is dominated by microholes, followed by transition holes. The development of mesopore and macropore is poor, because of the development of tectonic coal, the pore size structure and pore morphology of coal body in the study area are quite different. The average density of coal and rock fissures is 344 / cm ~ (-2), the average length and width are 2173 渭 m and 27.3 渭 m, and only 6.3% of the fractures are filled, the average adsorption volume of coal and rock is 9.9306 cm ~ (3) / g and the average adsorption pressure is 1.404 MPA / g. The permeability of coal and rock in the study area is negatively correlated with effective stress. According to the analysis of the condition of gas storage in raw coal, the coal seam burial depth is the main controlling factor of gas occurrence in raw coal, and the structural quantitative comprehensive evaluation is carried out in the study area. The maximum value of structural complex index is concentrated around F5 fault, and the gas content of raw coal decreases around F5 fault, and the basic area of lithology of top and bottom plate is mudstone with poor gas permeability, which is beneficial to the occurrence of raw coal gas. The study shows that the distribution of residual gas in the study area is controlled by structure, coal seam depth and coal thickness. The fault is relatively developed in the study area, and the small fault is the most developed. The content of residual gas is affected by structure, mainly because the development of small fault is favorable to the occurrence of residual gas, the deeper the coal bed is, the greater the difference of gas content is before and after drainage, which can effectively reduce the residual gas content, and the thicker the coal thickness, the more thick the residual gas content is. The greater the difference of gas content is, the lower the residual gas content and residual gas pressure are in the underground active area and near the roadway, which are not conducive to the occurrence of residual gas. The proportion of CO_2 in gas components decreased after drainage.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD712

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