In order to effectively solve the problems of difficult gas injection in S358 high pour-point reservoir and low oil displacement efficiency caused by gas channeling due to high mobility ratio of gas flooding after fracturing

laboratory experiments of gas injection phase and long core displacement mechanism have been carried out. Through the PVT phase state experiment of the high pour-point oil injected by CO

2

dry gas

flue gas

and oxygen-reduced air（N

2

90 %+O

2

10 %）under the formation conditions

the characteristic mec

hanisms of the above four injection gas such as the solubilization expansion

viscosity reduction and tension reduction have been analyzed. CO

2

is preferred as the injection gas. Through five groups of high temperature and high pressure long core flooding experiments with different combination methods

the effect of CO

2

combination flooding on channeling prevention and extraction is evaluated. The experimental results show that the displacement effects of both CO

2

+weak gel and CO

2

+foam are the best two

and the final displacement efficiency is 70.101 % and 68.212 % respectively. The research results show that the injection of CO

2

combined flooding slug increases the displacement resistance and reduces the fracture conductivity

which plays a key role in improving the microscopic sweep volume. Among them

both the CO

2

+weak gel and CO

2

+foam displacement methods have the best extraction effects. The research results can provide an experimental basis for the efficient development of high pour point oil in this block.