## 3 Air Injection Displacement Experiment of Different Pressure
### Oxidation Displacement Characteristics of Different Pressure Experiments
Figure 2: Temperature variation chart of different pressure experiments. produced. Therefore, the fuel consumed in the oxidation reaction increases, and the temperature of the oxidation front increases. In contrast, the content of light components in light oil is high, and the oxidation reaction fuel is mainly the residual heavy components after displacement [6]. The light oil is significantly affected by the distillation phase transition. The higher the pressure, the more obvious the effect of dissolution and distillation phase transition miscibility. The higher the oil displacement efficiency, the less the remaining oil after displacement at the oxidation front. Concurrently, the air consumption and fuel consumption of the oxidation reaction decreased, and the temperature of the oxidation front decreased accordingly. The air consumption in the heavy oil in situ combustion standard is defined as the volume of air consumed by the combustion zone sweeping through the unit volume of oil sands under standard conditions [21]. It is calculated as the ratio of the injected air volume to the volume swept through the oil sand in the stable stage of the heavy oil air injection experiment, and the gas storage in the pore volume is not considered in the calculation process. Using this standard, the air consumption of the 5 MPa experiment is 118.46 m\({}^{3}\)/m\({}^{3}\), the air consumption of the 15 MPa experiment is 129.49 m\({}^{3}\)/m\({}^{3}\), and the air consumption of the 30 MPa experiment is 144.78 m\({}^{3}\)/m\({}^{3}\). The calculation results show that under the same ventilation intensity, the air consumption of the 30 MPa experiment is the largest, and the corresponding oxidation front temperature should also be the highest. However, this result is obviously inconsistent with the experimental results that the front temperature is the highest under the condition of 5 MPa and the lowest under the condition of 30 MPa. The main reason is that the experimental pressure of heavy oil air injection is generally not more than 8 MPa [18]. The degree of injection gas compression during the experiment is low, and the gas storage is small. Therefore, the gas storage in the pores can be ignored. The calculated oxidation parameters can relatively accurately reflect the oxidation reaction characteristics. However, the formation pressure of light oil reservoir is high, and the degree of injection gas compression is high. In the process of the air injection experiment of light oil, the gas storage in pores is large. Therefore, the key parameters of oxidation in high-pressure light oil cannot be solved by copying the calculation method of heavy oil, and the method of calculating air consumption by heavy oil in situ combustion standard is not suitable for the calculation of oxidation parameters of light oil. Figure 4: Oxidation front temperature comparison chart of different pressure experiments. Considering the condition of gas storage, the air consumption of air injection in light oil was calculated, and the air consumption of light oil is defined as the air volume consumed by the oxidation front sweeping through a unit volume of oil sand minus the air volume stored in the pores. Table 3 shows the oxidation reaction parameters of different pressure experiments considering gas storage. It can be seen from the table that the air consumptions of 5 MPa, 15 MPa, and 30 MPa are 106.69, 92.50, and 76.81 m\({}^{3}\)/m\({}^{3}\), respectively. The air consumption and fuel consumption of 5 MPa are the highest, and the air consumption and fuel consumption of 30 MPa are the lowest. This is the same as the law that the temperature of the oxidation front decreases with the increase in pressure. Therefore, the calculation of oxidation parameters of high-pressure air injection needs to consider the influence of gas storage, which can more accurately reflect the oxidation state.