In this paper a semi-analytical approach for well productivity calculation in low-permeability and highly heterogeneous reservoir is proposed. Model considered allows explaining a high production rate decline for the wells operating in such conditions. Method of different interlayers flow capacity determination is considered based on identification of connected and isolated parts of the reservoir during waterflooding. Integration of rate transient analysis and steady-state production rate evaluation is used. Technique described can be used for the prediction of new wells production rate.