Multi-scale 3D characterisation of porosity and organic matter in shales with variable TOC content and thermal maturity: Examples from the Lublin and Baltic Basins, Poland and Lithuania

Different pore types have different diameters and total pore volumes: inter-mineral pores (0.2 μm, 10-94%), organic interface pores (0.2 μm, 2-77%), intra-organic pores (0.05 μm, 1-40%) and intra-mineral pores (0.05 μm diameter, 1-2% of total porosity). The major pore system in the studied shales is composed of inter-mineral pores which occur between clay mineral grains. TOC concentration influences the total volume of organic matter-related pores while maturity controls the presence of intra-organic pores. The study improves the understanding of the relationship of organic matter concentrations, maturity and pore systems in shales. This study characterises porosity and organic matter distributions in 3D; it also improves the understanding of the relationship of organic matter concentrations, maturity and pore systems in shales.