Abstract: To evaluate the feasibility of oil displacement using HW surfactant in Type Ⅱ conglomerate reservoirs in Wellblock B21, Karamay oilfield, the paper investigates the interfacial activity, stability, emulsifying property and simulated oil displacement performance of the surfactant. The results show that the magnitude of interfacial tension of HW surfactant concentration is 10-2 mN/m and the minimum interfacial is 0.006 0 mN/m when the mass fraction of HW surfactant is in the range of 0.1%~0.5%; the surfactant has good stability and its interfacial tension will not change during a long-term placement, which is in favor of enhancing oil recovery through reducing interfacial tension; the mass fraction and water-oil ratio of the surfactant have significant impact on emulsifying ability which increases with the increase of mass fraction, the water after demulsification is clear with distinct interface, which can help oil-water separation after oil displacement. The oil displacement experiment result shows that the surfactant solution with the mass fraction of 0.3% can improve the recovery factor by 10.5%