In order to effectively solve the CO

2

flooding gas channeling in Caoshe Oilfield

two kinds of gas-soluble foaming agents

fluorine-containing foaming agent（agent A） and silicon-containing foaming agent（agent B）

are evaluated from three aspects: dissolution

foaming and plugging

and one of them is selected as the CO

2

flooding sealing system in Caoshe Oilfield. The optimal injection concentration is 1.5 %. According to the experimental results

the solubility of agent A and agent B in supercritical CO

2

under the assistance of the co-solvent

etha

nol

reach 2.51 % and 1.93 % respectively

and both of them can form the dissolution conditions of stable foam. The comprehensive performance of foam produced by agent B is better than that of agent A. When the concentration of agent B reaches 1.5 %

the foaming performance is the best. Under the condition of high temperature（110 ℃） and high pressure（15 MPa）

the foaming volume reaches 261 mL

and the half-life period reaches 115 min. From the aspects of dissolution and foaming

agent B is optimized as the foam sealing system of CO

2

flooding in Caoshe Oilfield

and the evaluation experiments of CO

2

foam sealing ability under different injection modes are carried out. When CO

2

and foaming agent are injected alternately as the injection mode

the mixture is more uniform with more foam

and the resistance factor is high and can be more than 40

showing good foaming and plugging performance. The researches of sealing channeling system provide a new technical support for preventing gas channeling in CO

2

flooding of Caoshe Oilfield.