针对我国煤层开采地质条件复杂、含煤地层中煤层群广泛发育、突出煤层群瓦斯灾害严重的特征,采用理论分析、数据统计和工程实践相结合的方法,系统分析了我国深部煤储层渗透特征,即深部煤体呈天然粉化结构,微、小孔发育,渗透率通常小于10~(-6)μm~2;提出了应依据安全性、经济性和统筹规划的首采关键层选择内涵和首采关键层"钻孔卸荷"的理论模型,确定在埋深大于800 m时,吨煤钻孔长度、钻孔间距等定量化关键指标;在此基础上,介绍了我国采用地面井压裂、井下顺层钻孔和穿层钻孔改造首采关键层的技术途径,配合邻近层卸压瓦斯抽采方法构成立体瓦斯抽采模式,实现了高瓦斯突出矿井煤与瓦斯2种资源的安全高效开采。
In view of the complicated geological conditions of coal mining in China, the extensive development of coal seams in coal-bear- ing strata and the serious occun'ence of gas disaster in outburst coal seam group, this paper analyzes permeability character of deep coal reservoir by combining theoretical analysis, data statistics with engineering practice and it shows that deep coal is natural pulverized and developed in micro, small pore with permeability usually less than l0-6 I.Lm2.It proposes the connotation of the key first mined seam selec- tion which is security, economy and master plane as well as the theoretical model of "drilling and unloading" for the key first mined seam. This paper ascertains the quantifying key indicators for ton coal drilling distance and bore space when burial depth is more than 800 m.On this basis, it is introduced that the technology approach for surface remaking by using hydraulic fracturing well and underground remaking by using bedding and piercing boreholes in China, which could cooperate with the pressure-relief gas extraction methods for the adjacent coal seams and form a three-dimensional gas extraction technology system, realizing a safe and high efficient development of coal and gas resources in high gassy outburst coal mines.