聚焦离子束扫描电镜研究微体化石的微观孔隙结构

A Study into the Microscopic Pore Structure of Microfossils with Focused Ion Beam Scanning Electron Microscopy(FIB-SEM)

聚焦离子束扫描电镜(FIB-SEM)是将聚焦离子束切割和扫描电镜结合起来的双束系统,可以在纳米尺度对样品进行切割加工与实时成像。文中用聚焦离子束扫描电镜对兰多维列统(志留系)龙马溪组黑色页岩内的几类微体化石进行了观察研究,并显示牙形刺、几丁石、疑源类均发育有亚微米至纳米级孔隙,这些孔隙可以为页岩气的储集提供有效空间,不同的微体化石孔隙发育的差异可以为页岩中有机质孔隙非均质性成因研究提供重要依据。

Focused ion beam scanning electron microscopy(FIB-SEM) is a dual beam system which combines focused ion beam (FIB) and scanning electron microscopy (SEM) to cut samples and display real-time images at nanometer scale. This study observed several kinds of microfossils from the Lungmachi Formation (Llandovery, Silurian) with FIB-SEM. The results reveal that submicron-nano pores, which provide valid space for shale gas reservoirs, are well-developed in conodonts, chitinozoans and acritarchs. Disparities of micro-pores in different fossil groups shown in this study will help to explain the cause of organic pore heterogeneity in shales.