Dynamic network model, validated by comparing with the previous studies, is presented for investigating pore-scale displacement and oil recovery in dilute surfactant flooding (DSF), which is an economically enhanced oil recovery (EOR) technology. The objective is to study the effects of water/oil interfacial tension (IFT), injection rate, and oil viscosity on oil recovery in DSF and the corresponding water flooding (WF). The results indicate that oil recovery increased with the reduction of IFT and the increase of the viscosity ratio. Displacement patterns also reveal that relatively large sweep efficiency can be achieved by using DSF.