To improve the understanding of spatial heterogeneity in fine-grained shale, methods of microscale X-ray fluorescence (μ-XRF) mapping, (ultra-) small-angle x-ray scattering [(U)SAXS] and wide-angle X-ray scattering were used to determine elemental and pore structure variations in sizes up to ~10 cm on two samples prepared at circular (8 cm×8 cm×0.8 mm in width×length×thickness) and rectangular (5 cm×8 cm×0.8 mm) orientations from a piece of Eagle Ford Shale outcrop in South Texas. Thin section petrography and field emission-scanning electron microscopy, X-ray diffraction (XRD), total organic carbon, and pyrolysis were also utilized to investigate the potential spatial heterogeneity of pore types, mineral and organic matter compositions for both samples. Overall, the siliceous-carbonate mineral contents in these carbonate-rich Eagle Ford Shale vary between laminations at mm scales. For the circular sample, porosity and surface area variations range from 0.82 to 3.04% and 1.51 to 14.1 m²/g, respectively. For the rectangular sample, values for porosity and surface area vary from 0.93 to 2.50% and 3.95 to 10.8 m²/g. By analyzing six selected sub-samples on each of two samples with X-ray scattering and XRD techniques, nm-sized pores are mainly interparticle ones in the higher calcite regions, where the porosity is also relatively lower, while the lower calcite regions consist of both interparticle and intraparticle pore types with higher porosity. Finally, the μ-XRF and (U)SAXS are combined to generate porosity distribution maps to provide more insights about its heterogeneity related to the laminations and fractures at our observational scales.