新元矿3号煤微孔裂隙特征研究

Study on the Characteristics of the No.3 Coal Micropore Fissures in Xinyuan Mine

煤孔裂隙是控制煤层气吸附、解吸、扩散、渗流等的关键因素,其研究对井上下煤层气抽采具有重要指导意义。为了揭示新元矿3号煤微孔裂隙特征,采用扫描电镜对该矿3号煤微孔裂隙进行了观测研究。结果表明:新元矿3号煤中发育有气孔、角砾孔和摩擦孔等3种不同成因类型孔隙,孔隙的形态多样,孔隙大小一般为几百纳米至几十微米,孔隙基本不连通且被少量碎屑物充填,角砾孔连通性好但结构不稳定。煤中发育张裂隙和剪裂隙,裂口宽度一般为数百纳米至20μm,呈张开状且裂口中有少量煤屑所充填;张裂隙产状不稳定,延伸短且多呈弯曲状;剪裂隙产状稳定,定向延伸长;裂隙面粗糙程度不一,张裂隙面粗糙,剪裂隙面光滑平直。

Coal pore fissures are key factors in controlling the adsorption,desorption,diffusion,and seepage of coalbed methane and its research has important guiding significance for coalbed methane extraction above and below the well.In order to reveal the micropore fissure characteristics of the No.3 coal in Xinyuan Mine,the author has conducted a large number of observations and researches on the microporous fracture of No.3 coal in this mine using scanning electron microscopy.The results showed that:Xinyuan Mine No.3 coal has three types of pores of different genetic types,including stomatal,breccia pores and friction pores.The pores have various shapes,and the pore size is generally several hundred nanometers to several tens of micrometers.The pores are basically disconnected and filled with a small amount of debris,breccia pores has good connectivity but unstable structure.Tensile and shear fissures are developed in the coal.The width of the cleft is generally hundreds of nanometers to 20 μm,which is open and filled with a small amount of coal debris.The occurrence of tension fissures is unstable,and the extension is short and mostly curved.Shear fissures have stable appearance and long directional extension.Tension crack surface is rough,shear crack surface is smooth and straight.