Abstract Corrosion prediction in multiphase flow has been a challenging task in oil and gas industry for many years. Strictly speaking, the existing mechanistic CO2 corrosion models can only be used in single-phase flow. To add the capability of predicting corrosion in multiphase flow, the mass transfer and the turbulent diffusivity correlations in the models have to be modified to properly calculate the mass flux of corrosion species. An approach for establishing these correlations in different flow regimes is presented. The implementation of the method for stratified flow proves the feasibility of this proposal.