摘要
Electron microbeam techniques include scanning electron microscopy, environmental scanning electron microscopy, electron probe microanalysis, transmission electron microscopy, and scanning transmission electron microscopy.Signals generated in an electron microscope provide information on image, chemistry and crystal structure of a sample at micro-and nano-scale.These techniques are suitable tools for investigating and characterizing the microstructure and mineralogy of oil-or gas-bearing rocks such as shale and dolomite.A preliminary SEM imaging study of shale and dolomite samples from the 2nd member of Kongdian Formation, Changdong Sag, Bohai Bay basin, China reveals that micro-and nano-scale pores or fractures are ubiquitous, existing not only interstitially among minerals, but also on the surface of crystal grains.Sizes of the pores are as small as a few nanometers.Some pores or fractures penetrate into the interior of a crystal.Microanalytical study of the rocks from the Kongdian Formation by energy dispersive spectrometer confirms that the major minerals are clay minerals and dolomite and that there are abundant organic matters in these rocks.Other minerals identified include plagioclase, quartz,oxides, sulfides, barite, etc.