3.1.7 Adsorption and Desorption

Preferential sorption occurs when CO2 molecules attach to the surfaces of coal and certain organic-rich shales, displacing other molecules such as methane. Dynamic permeability models (Shi and Durucan, 2005; Palmer and Mansoori, 1996) account for the impact of matrix swelling (caused by CO2 injection) as well as matrix shrinkage (caused by methane production or N2 Flooding) on the formation permeability and thus allow the absolute permeability of the seams to be updated at the end of each time step during a simulation run.