3.1.1. Ventilation Intensity

From the simulation results, when the ventilation intensity of the injection well was less than 0.55 m<sup>3</sup>/(d.m2), the formation would not form oil-wall and fire-wall. In addition, the combustion leading edge temperature was lower than 220 ◦C, showing a low temperature oxidation state. At the end of the production, the maximum temperature of the formation was less than 220 ◦C. The highest temperature zone existed at the injection well. And there was no tendency to advance to the production well and no fire wall was formed. In the simulation, the pressure difference between the injection and production well was 7.4 MPa, which means the injection well pressure was much higher than the production well. It can be found that if the ventilation intensity and oxygen was not enough, it was di fficult to maintain the fuel supply and the formation oxidation reaction. It can be concluded that the air injection speed should be increased to maintain stable combustion and meet the development of the in-situ combustion.
