Pore anisotropy in shale and its dependence on thermal maturity and organic carbon content: A scanning SAXS study

Pore orientation in shale governs the fluid transport properties that are key to hydrocarbon production and potential CO2 sequestration. The present work deals with the detailed study of nano-heterogeneities in shales, across the bedding plane, of varying thermal maturity and total organic carbon content using scanning smallangle X-ray scattering (SAXS) experiments. The complementary X-ray Micro-Computed Tomography (& mu;CT) and functional group mapping elucidate the heterogeneity in micrometer resolution. 2D SAXS profiles of the shales show elliptical patterns indicating the nanoscale pore anisotropy in shale. The orientation of pores and their spatial variation is strongly dependent on the content of organic matter. The variance in the anisotropy parameter is validated with chemical mapping and high-resolution 3D imaging.