On the Use of Imaging Methods in Characterizing the Pore Space of Clay Rocks in 3D

In the context of the disposal of radioactive waste, the production of shale gas and CO2 sequestration gas transport along the intergranular pore space in clay rock formations is an important issue. In order to validate the isolation potential of a host rock for radioactive waste or in order to better understand the deliverability of gas of shale gas reservoirs, the gas transport pathways and their connectivity have to be comprehend very well. It is well known that the intergranular pore system is dominated by pores with radii on the nanoscale; whereas it is proposed that gas flow is controlled by the geometry of those pores that corresponds to comparable larger pores (i.e. > 10nm). Thus, information on larger pore connectivity, geometry and distribution are important. In addition, and in the case of gas shales, micron-scale carbonaceous particles are associated with an increased nanoporosity and it is assumed that this organic material forms pathways for locally enhanced gas transport. In addition to organic material, silty-sandy layers in different sizes are potential pathways for enhanced transport through an otherwise largely impermeable matrix of fine grained clay grains of which a majority of pores have radii < 10 nm.