Apparent permeability of organic matter in shale considering pore size distribution

The gas flow in shale nanopores is a crucial factor for shale gas exploitation. Organic matter in shale is an important constituent of gas shale reservoirs because of its gas storage ability. Current apparent perme-ability (Kapp) models focus on permeability calculations derived from pores with a given diameter or given mathematical distribution instead of pore size distribution. We confirmed the gas mass flux in organic matter by modifying the molecular diffusion coefficient and adsorption amount related to surface diffusion and flow regime transformation critical conditions such as pore size and pressure. Then, Kapp was calculated by coupling the mass flux with the pore size distribution. Our research shows that steps occur in the Kapp curves of organic matter owing to the flow regime transformation from transition flow to slip flow. Additionally, porosity, dominant pore diameter and frequency were the main factors affect-ing the Kapp of organic matter.CO 2022 Elsevier Ltd. All rights reserved.