Abstract: Zheng 408 Block is a typical strong water sensitive heavy oil reservoir. The recovery performance of natural drive，
anti-swelling water flooding and steam huff and puff is unsatisfactory for the shortage of natural energy and strong water sensitivity.
Based on indoor experiments，the dissolution of CO2 in heavy oil of Zheng 408 Block and the percolation characteristics
in production period were studied. The optimization of development scheme was obtained by numerical simulation. The results
show that the volume of heavy oil increases obviously and the heavy oil viscosity will decrease greatly after the dissolving of
CO2. In CO2 huff and puff production period，CO2 precipitated in heavy oil disperses in oil like small gas bubbles because of
high viscosity，which can be defined as“foamy oil”. Foamy oil can improve the flow ability of heavy oil，increase elastic
energy and decrease the velocity of reservoir pressure drop. Numerical simulation results show that the optimal cyclic CO2
injection volume was 100 t，and the optimal injection rate was 50 t/d.

Key words: heavy oil, water sensitivity, CO2, numerical simulation, percolation characteristics