There are a variety of pore types in unconventional resource shales The preferred method for examining and analyzing these shales is by focused ion beam milling (FIB) to produce an ultra-smooth surface, coupled with observation under the field emission scanning electron microscope (FESEM). Potential issues with FIB-FESEM preparation and imaging include:

  • the small size of sample cubes for upscaling,

  • loss of structural fabric during the milling-imaging process,

  • fewer non-organic pore types observed than with an unpolished surface,

  • analog use of pores from one shale to another, even though the pore types may differ, and

  • the effects of sample retrieval from the subsurface to the surface environment on microfabric and pore distribution.

Conventional FESEM imaging of unpolished shale surfaces should not be overlooked in shale resource studies as a cost-effect method for estimating porosity and determining pore types and their distribution in shales.

This content is only available via PDF.
You can access this article if you purchase or spend a download.