Mineral and organic matter compositions & pore structures of fine-grained shale influence reservoir properties. To improve the understanding of spatial heterogeneity in core-sized samples, methods of microscale X-ray fluorescence (μXRF) mapping, (ultra-) small-angle x-ray scattering [(U)SAXS] and wide-angle X-ray scattering (WAXS) have been used to determine elemental, pore-structure variations at scales up to ~10 cm on two samples prepared at circular and rectangular orientations from a piece of Eagle Ford Shale outcrop in South Texas, USA. In addition, thin section petrography and field emission-scanning electron microscopy observations, X-ray diffraction (XRD), total organic carbon, and pyrolysis were utilized to investigate the potential spatial heterogeneity of pore types, mineral and organic matter compositions for cm-sized samples at both orientations. Overall, the siliceous‑carbonate mineral contents in these two samples (8 cm × 8 cm × 0.08 cm and 5 cm × 8 cm × 0.08 cm, in terms of width×length×thickness) of carbonate-rich Eagle Ford Shale vary between laminations at mm scales. For the circular sample, porosity and specific surface area (SSA) 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 SSA 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 (U)SAXS 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 μXRF and (U)SAXS mappings are combined to generate porosity distribution maps to provide more insights about sample heterogeneity related to the laminations and fractures at our observational scales.

细粒页岩的矿物和有机质组成及孔隙结构影响储层特性。为了提高对核心大小样品空间异质性的理解，微尺度 X 射线荧光 (μXRF) 映射、（超）小角 X 射线散射 [(U)SAXS] 和广角 X 射线散射的方法(WAXS) 已被用于确定在美国南德克萨斯州的一块鹰福特页岩露头上以圆形和矩形方向制备的两个样品上高达 ~10 厘米的元素、孔隙结构变化。此外，还利用薄片岩相学和场发射扫描电子显微镜观察、X 射线衍射 (XRD)、总有机碳和热解来研究孔隙类型的潜在空间异质性，两个方向上厘米大小样品的矿物和有机物质组成。总体而言，富含碳酸盐的 Eagle Ford 页岩的这两个样品中的硅碳酸盐矿物含量（8 cm × 8 cm × 0.08 cm 和 5 cm × 8 cm × 0.08 cm，以宽×长×厚计）在层状之间存在差异在毫米尺度。对于圆形样品，孔隙率和比表面积 (SSA) 变化范围为 0.82 至 3.04% 和 1.51 至 14.1 m² /g，分别。对于矩形样品，孔隙率和 SSA 的值在 0.93 到 2.50% 和 3.95 到 10.8 m ² /g 之间变化。通过使用 (U)SAXS 和 XRD 技术对两个样品中每个样品的六个选定子样品进行分析, 纳米尺寸的孔隙主要是在较高方解石区域的颗粒间孔隙, 孔隙率也相对较低, 而较低方解石区域由具有较高孔隙率的颗粒间和颗粒内孔类型。最后，结合 μXRF 和 (U)SAXS 映射以生成孔隙度分布图，以提供更多关于在我们的观测尺度上与层状和裂缝相关的样品非均质性的见解。