Quantitative Analysis of Pore-Network and Permeability Estimation in Deformed Porous Carbonate Grainstones

This study investigates the pore-network properties and the permeability of deformed porous carbonate grainstones located in Northwestern Sicily and Abruzzo region, Italy. Even though the studied grainstones present similar values of porosity, their permeability varies between three to four orders of magnitude. In order to explain this permeability difference, we performed a three-dimensional quantitative analysis of the pore-network including porosity, pore connectivity and specific surface area. For assessing those properties, samples of deformed carbonate grainstones were scanned implementing X-ray computed microtomography techniques. In addition, permeability was computed by means of Lattice-Boltzmann simulation. The effect of each pore-network property (porosity, specific surface area, pore connectivity) on permeability was evaluated by means of scatter plots considering both host rocks and deformation bands. In the highly porous host rock, the permeability is mainly controlled by the specific surface area, which is linked to both grain size and roughness. Within deformation bands, permeability reduction is related to low pore-network connectivity caused by compaction and cementation.