SAXS and WAXS microscopy applied to mudrocks: A new method for systematic multiscale studies of porosity, pore orientation and mineralogy

We apply scanning SAXS and WAXS microscopy to different mudrock samples. The method characterizes the microstructure in terms of porosity and preferential pore alignment of small pores 6 -202 nm size. These small features are experimentally challenging to resolve for statistically relevant sample volumes with state of the art characterization techniques, such as imaging methods. A key novelty in this study is the quantification of the mineralogy and mineral phase content from the WAXS measurements. Thus, a detailed quantification and comparison of important microstructural parameters is achieved. The method is used in a raster scanning mode, where thousands of consecutive measurements are performed, with a high micrometric spatial resolution, over mm sized sample areas. Therefore, simultaneously the variation of the microstructure is resolved on the pore and lamina scale. We propose to use scanning SAXS-WAXS microcopy in future studies for investigations of the systematic relationships between mineralogy and the pore network.