郑庄井田3号煤微孔裂隙特征研究

Study on Characteristics of Micropores and Fissures of the No.3 Coal in Zhengzhuang Mine Field

煤孔裂隙控制着煤层气赋存和运移,对煤层气生产实践具有重要影响。为了研究郑庄井田3号煤微孔裂隙特征,采用EVO 15型扫描电子显微镜对井田3号煤的微孔裂隙进行了观测和精细表征研究。结果表明:郑庄井田3号煤中微孔隙有气孔、铸模孔、溶蚀孔和角砾孔,不同孔隙的形态、大小和连通性等均不同。孔隙形态多样,孔隙大小一般几十纳米至几十微米,孔隙的连通性整体较差,常见碎屑物充填孔隙。煤中微裂隙为张裂隙和剪裂隙,张裂隙延伸短、产状不稳定、裂隙面粗糙、裂口基本为张开状。剪裂隙延伸相对较长、产状稳定、裂隙面光滑、裂口部分张开。张裂隙和剪裂隙被碎屑物和方解石脉充填现象常见,但剪裂隙被充填现象更严重。

Coal pore fissures control the occurrence and migration of coalbed methane,and have an important impact on the production practice of coalbed methane.In order to study the characteristics of micropores and fissures of the No.3 coal in Zhengzhuang Mine Field,EVO 15 scanning electron microscope was used to observe and finely characterize micropores and fissures of the No.3 coal in Mine Field.The results show that there are pores,mold pores,dissolution pores and breccia pores in the No.3 coal in Zhengzhuang Mine Field,and the shape,size and connectivity of different pores are different.Pore morphology is diverse,pore size generally ranges from tens of nanometers to tens of microns,the connectivity of pores is generally poor,and common debris fills pores.Micro-fractures in coal are tensile fractures and shear fractures,with short extension,unstable occurrence,rough fracture surface and basically open cracks.Shear fissures extend relatively long,with stable occurrence,smooth fissure surface and partially open fissure.It is common for tensile fractures and shear fractures to be filled with detritus and calcite veins,but it is more serious for shear fractures to be filled.