Abstract: CO₂ foam profile/water plugging technique is a selective chemical method, the key point of which is the selection of foaming agent. In view of the particular reservoir with high temperature and high salinity, a comprehensive survey of critical factors affecting the foaming agent behaviors is conducted, by which the surfactant YFP-2 with good salt resistance, temperature tolerance and pH stability is selected as the main foaming agent. Also, this paper studies the sealing effect of this foaming agent on the displaced cores under the environment of analog reservoir by means of core flow test. The result shows that this CO₂ foam system has stronger flow resistance holding capacity and function to change flow direction in the rock.

Key words: high temperature, high salinity, CO₂, foam, foaming agent, water plugging