以渝东南地区渝页1井和黔西北地区习页1井、桐页1井的下志留统龙马溪组页岩岩心样品为研究对象,使用场发射扫描电镜观察孔隙的微观形态,并通过X射线微米CT扫描提取孔隙的空间结构参数,力求从二维、三维层面分别对页岩的孔隙进行特征定性.由扫描电镜观察知,研究区页岩气储层发育粒间孔、粒内孔、有机质孔及微裂缝等多种类型,孔隙多为宏孔(>50 nm)及中孔(2~50 nm).粒间孔中,矿物晶粒间孔发育较广泛;粒内孔以矿物集合体内孔为主,如"草莓状"黄铁矿结核内的晶间孔隙;有机质孔多为圆形、椭圆形的宏孔及中孔.通过CT扫描和孔隙模型的三维重建可知,孔隙多呈孤立状、条带状分布,连通性较差.

Pore space is characteristic in Lower Silurian Longmaxi shale reservoirs in southeastern Chongqing and northwestern Guizhou areas.Shale samples are collected from Wells YY-1,XY-1 and TY-1 in the areas.Observed with SEM,four types of pores can be recognized,including intergranular pores,intragranular pores,organic-matter pores and microfractures,most of which are macropores (>50nm) and mesopores (2~50nm).Mineral intercrystalline pores are common in intergranular pores.Mineral aggregates,such as pyrite framboids,are general in intragranular pores.Organic-matter pores are mostly round or elliptic with large sizes as macropores and/or mesopores.By the micro-CT scanning to part of samples,the 3-D structure models of nanometer-scaled pores are re-established.It is shown that most micropores are isolated or stripped with poor pore networks and connectivity in Longmaxi shales.