To clarify interconnected pore network, blue dyed epoxy impregnated thin sections of various rocks were prepared. Careful microscopic photographic studies of thin sections were able to distinguish pores from grains. Pores are measured clearly by the presence of blue dyed epoxy. This blue dyed epoxy impregnation method was most suitable for rocks with porosity above a few percent, and for fractured rocks with ultimate fracture planes. Specific microcracks with width above 10 micron meter are detected clearly in granitic rocks.
Using an image processing technique, porosities and aspect ratios of pore were estimated from the segmented microsections. Porosities measured from the image, in general, different from that of the physical tests. The porosity of the Shirahama sandstone decreased by about 2% after stressed to 49 MPa. The low aspect ratio pores of the Shirahama sandstone closed completely after stressed to 49 MPa.
