The influence of both Dysktra- Parkson coefficient and formation rhythm on alkaline / surfactant / polymer (ASP) system has been investigated at length through the combination of numerical simulation with core flooding in the light of Da Qing specific reservoir conditions. The results showed that as long as the Dysktra-Parkson coefficient is less than 0.85, the recovery can go up by increasing the viscosity of ASP system to improve the oil-water mobility and swept volume. However, regarding serious heterogeneous formation, high viscous ASP system is required to control the oil-water mobility, which will
consume a great deal of polymer, therefore the cost would go up greatly. Furthermore, due to gravity segregation, the ASP swept recovery is better than that of waterflooding within regular rhythm formation, while within negative rhythm formation,the ASP swept recovery is worse than that of waterflooding. In a word, Dysktra-Parkson coefficient and formation rhythm are two important factors which affect the application of ASP technology and we should pay much attention to them in oilfield test practice.