Plain Language Summary
Geological samples have a wide range of heterogeneity at different
sampling and analytical scales. Cores are usually analyzed after
plugging, cutting, and/or crushing which will lead to the issues of
inability of studying, and altering, the heterogeneity at the
decimeter-scale. This study investigates the areal heterogeneity of
mineral compositions, pore structure, and organic matter composition on
two sub-dm-sized samples from an outcrop of Eagle Ford Shale.
Complementary and integrated approaches of X-ray fluorescence for
microscale mapping, (ultra-) small-angle x-ray scattering for pore
structure characterization of pore diameters at 1-1000 nm, and
wide-angle X-ray scattering for mineral types, in addition to thin
section petrography, field emission-scanning electron microscopy, X-ray
diffraction, total organic carbon analyses, and pyrolysis, were utilized
to investigate the spatial heterogeneity of pore types, mineral and
organic matter compositions to derive the correlation of porosity
distribution and sedimentary features. This work illustrates the
capabilities of relatively quick and non-destructive sampling of
dm-scaled sizes and analytical scales of μm-cm for areal heterogeneity
studies of natural rocks in various geophysical applications.