【作者】 秦伟；

【导师】 许家林；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2013， 博士

【摘要】 老采空区瓦斯抽采技术是将老采空区内遗煤、煤柱及邻近煤岩层不断解吸释放的瓦斯抽采至地面的煤矿瓦斯抽采技术，是煤与瓦斯共采技术体系的重要组成部分。老采空区瓦斯富集规律、老采空区裂隙场横向分布特征、地面钻井井位选择及井网布置是老采空区瓦斯资源开发亟待解决的关键问题，而我国老采空区瓦斯抽采技术研究起步较晚，相关基础理论研究仍处于空白阶段。针对上述问题，本文结合“十二五”山西省科技重大专项(20111101004)开展了地面钻井抽采老采空区瓦斯的理论研究。理论分析了老采空区瓦斯的赋存状态，揭示了老采空区瓦斯的来源，根据采动上覆瓦斯卸压运移“三带”理论确定了老采空区瓦斯的赋存范围，在此基础上利用分源法建立了老采空区瓦斯储量预测模型。在明确采空区导气裂隙带发育高度的基础上，将导气裂隙带在横向上划分为：侧向裂隙区、“O”形圈裂区和重新压实区，就工作面采高、覆岩关键层结构及采深对各横向分区发育形态的影响进行了数值模拟研究。研究结果表明：工作面采高是影响各横向分区发育形态的主要因素，侧向裂隙区超出开采边界的最大距离、“O”形圈裂隙区宽度均随工作面采高的增大而增大，在此基础上给出了考虑工作面采高、覆岩关键层结构及采深的各横向分区发育特征的判别方法，研究结果对老采空区瓦斯地面抽采钻井的井位选择和井网布置具有重要指导意义。通过自行研制的“采空区瓦斯抽采模拟试验系统”开展了老采空区地面井位优化的物理模拟试验研究，结果表明：地面钻井的抽采混合量整体呈不断衰减趋势，当抽采负压相同时，位于“O”形圈裂隙区的钻井抽采混合量较大，瓦斯浓度有小幅上升，“O”形圈裂隙区是地面钻井布置的最佳区域。对采空区覆岩垂直位移进行了监测，拟合得到了采空区覆岩垂直位移空间分布函数，在此基础上推导了采空区渗透率的空间分布函数，建立了老采空区瓦斯渗流数学模型，并通过FLUENT软件对该数学模型进行了求解。研究结果表明：布置在“O”形圈裂隙区内的地面钻井控制范围较大，湍流区面积较大，随着地面钻井不断深入采空区中部的压实区，地面钻井控制范围不断减小，湍流区面积也不断减小。将老采空区瓦斯抽采的基础理论应用于阳泉矿区的老采空区瓦斯抽采试验，利用老采空区横向连通及纵向连通判据，对阳泉三矿老采空区进行了区域划分。利用老采空区瓦斯储量预测模型，对各连通区域的老采空区瓦斯储量进行了预测，确定了首批地面钻井的施工区域。根据地面井位优化和地面钻井控制范围的研究结果，指导了阳泉三矿老采空区地面井位选择和井网布置。更多还原

【Abstract】 Abandoned gob methane drainage technology is to pump methane that is hosted inresidual coal, coal pillar and adjacent coal seams to the surface. This is an important part ofthe simultaneous extraction of coal and gas technology system. The understanding ofmethane accumulation and distribution, and the study of the position and arrangement ofthe surface well are the key problems issues of the abandoned gob methane drainagemethod. However, related study is presently not undertaken in China, and the basictheoretical study is a blank. Motivated by the problems mentioned above, this dissertationconducted theoretical study of methane drainage from abandoned gob by surface wells,which is partially sponsored by the key Shanxi science and technology project(20111101004).In this dissertation, the occurrence and sources of abandoned gob methane aretheoretically analyzed, and the occurrence scope of abandoned gob methane was obtainedbased on the “three-zone” theory of the overlying strata. A model was built to estimateabandoned gob methane reservoir based on the “three-zone” theory.In the foundation of clear about the height of the gas conductive fracture zone, gasconductive fracture zone was divided into lateral fissure zone,“O” shape fissure zone, andcompacted zone in the horizontal direction. Numerical simulation was used to study theinfluence of mining height, the overlying key stratum structure, and the mining depth ondevelopmental characteristics of horizontal partitions. The research results showed thatcharacteristics of the horizontal partitions are mostly affected by mining height. With theincrease of the mining height, the maximum distance of lateral fissure zone form themining boundary and the width of the “O” shape fissure zone increase. A method wasdeveloped to estimate the characteristics of the horizontal partitions by considering themining height, the overlying key stratum structure, and the mining depth. The researchresults are important in the selection of surface well position and arrangement for methanedrainage from abandoned gob.A gob methane drainage physical simulation system was used to conduct laboratoryexperiments for the optimization of the methane drainage surface well. The laboratoryexperiments showed thatthe methane flow quantity of the surface well decreasescontinuously with time, and the surface well in the “O” shape fissure zone has a larger gasflow quantity. The “O” shape fissure zone is the best area for the location of the surfacewell. Based on the monitored vertical displacement of the overlying strata, a spatial distribution function of the vertical displacement of overlying strata was obtained. Aspatialdistribution function of the gob permeability was proposed and a CFD modeling study wasconducted. The research results showed thatthe surface well in the “O” shape fissure zonehas a larger control region and turbulence region, and the control region of a surface welldecrease when it gets closer to the middle of the gob.The developed theory was applied to theYangquan Mining Area. Based on thecriterion of abandoned gob’s connection,the region division was carried out in YangquanCoal Mine NO.3.Abandoned gob methane reservoir in the connected region was predictedby the reservation calculation model, and the construction region of the firstsets surfacewells were determined. Selection of surface well position and arrangement of surfacewellwas carried out in theselected region according to the study of optimizationarrangement of Surface Well Network and Surface well position.更多还原