The integration of magnifications: A novel approach to obtain representative information about the pore space of mudrocks from SEM images

High resolution Scanning Electron Microscopy (SEM) imaging has been widely used to characterize the pore space of mudrocks. However, obtaining representative microfabric information has been limited by the highly heterogeneous microstructure of mudrocks, which contains pores and particles spanning several length scales. The integration of magnifications (IOM) method was developed to obtain representative information about the pore space of mudrocks. This method combines information from SEM images acquired at different magnifications to characterize the pore space. High magnification images with high resolution are used to quantify small pores and low magnification images with lower resolution are used to quantify large pores. These different scales are then mathematically combined to obtain a complete pore space representation. The method was validated using 2D Monte Carlo simulations applied on a synthetic 2D microstructure with a prescribed porosity and pore size distribution. The applicability of the method was illustrated by computing the porosity and pore size distribution of two naturally resedimented mudrocks. The IOM method provides a practical and economical alternative to the current cumbersome methodology that stitches together hundreds to thousands of SEM images to obtain large representative mosaics.