Modelling of wellbore cement alteration due to CO2-rich brine interaction in a large-scale autoclave experiment

•A full-scale laboratory experiment under reservoir conditions to study the cement and CO2-rich brine interaction has been modelled.•The reactive transport model quantifies mineral alterations and porosity changes in the interface cement and CO2-rich brine.•A diffusion coefficient of 6.4x10-10 m2s-1 has been obtained by calibration using the alteration area detected experimentally.•The porosity partially increases due to C-S-H-gel and portlandite dissolution and strongly decreases mainly due to calcite but also C-A-S-H and M-S-H precipitation.