【摘要】 煤矿瓦斯灾害是世界煤炭行业公认的重大灾害之一。在进行低渗透煤储层渗透特性改造试验时,采用了大尺寸的煤体试件(500mm×500mm×500mm)进行试验,在该煤体试件中不仅包含了较多孔隙,而且还包含了几条较大的裂缝。在对试件进行钻孔瓦斯抽放和割缝瓦斯抽放试验过程中,均首次观测到大规模的瓦斯突出现象,而在以往小尺寸煤样瓦斯渗流试验中则从未发现过类似现象。这种现象充分说明,对于煤体这样孔隙、裂隙发育的岩体,标准尺寸的试件往往难以包含足够多的岩体信息,采用大尺寸岩石试件后,所观察到的试验现象将更加接近于工程岩体实际,所测得的试验数据会更真实。更多还原

【Abstract】 Gas of coal mine is one of the most hazardous problems in coal industry of the world. In China, the lower permeability of coal is the main character which limits the development of gas extraction industry. In this testing study of gas extraction from low permeability coal, the big coal samples(500 mm × 500 mm × 500 mm) are used. There are many pores and fractures in these samples. While the coal mass is under fracturing, the gas outbursts intermittently. This phenomenon is never reported in articles before while small samples had been used. So we can conclude that when big samples are used, each sample can contain more information which leads to the experiment result closer the in-situ rock test. The experiment results also reveal that to release the initial earth stress is a better way to improve the permeability of coal. Water fracturing method is one of the efficient methods to release the initial earth stress.更多还原