W-shaped permeability evolution of coal with supercritical CO2 phase transition

Gaseous CO2 becomes a supercritical liquid when temperature and pressure transit the critical point (31.1 °C and 7.4 MPa) – a typical state for CO2 storage for carbon sequestration and CO2 injection in enhanced coalbed methane/shale recovery. Therefore, it is essential to define the evolution of coal permeability inclusive of this phase transition. This study presents experimental measurements of coal permeability across the CO2/SCCO2 transition...