## 4 Air Injection Displacement Experiment of Light Oil Reservoir After Water Injection
### Oxidation Displacement Characteristics of Experiment After Water Injection  
Figure 7 shows the temperature variation curve of the air injection experiment after water flooding. As shown in Figure 7, the temperature of the oxidation front of air injection \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Numbering**} & \multirow{2}{*}{\begin{tabular}{c} **Experimental** \\ **Pressure, MPa** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Oil Saturation, \%** \\ **to, \%** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Saturated** \\ **Oil Volume,** \\ **mL** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Total Liquid** \\ **Production,** \\ **mL** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Total Oil** \\ **Production,** \\ **mL** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Total Gas** \\ **Production,** \\ **L** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Gas** \\ **Production-** \\ **Injection Ratio** \\ \end{tabular} } \\ \hline
1 & 5 & 85.45 & 805.00 & 848.61 & 728.54 & 277 & 0.91 \\
2 & 15 & 84.65 & 818.43 & 955.09 & 760.61 & 239 & 0.76 \\
3 & 30 & 84.59 & 830.00 & 945.75 & 761.94 & 188 & 0.56 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Cumulative production dynamic parameters of different pressure experiments. Figure 6: Oil displacement efficiency and production gas-oil ratio chart of different pressure experiments. after water injection is above 350 \({}^{\circ}\)C, the oxidation front can be steadily advanced, and the oxidation state of air injection after water injection is stable. Table 5 is the gas composition table of air injection and air injection after water injection experiments. In terms of the content of the produced gas, the average oxygen content of the produced gas in the air injection experiment after water injection is 2.03%, the average carbon dioxide is 12.49%, and the methane content is 4.71%. This shows that the oxygen consumption of the oxidation reaction is sufficient, and a stable high-temperature oxidation reaction occurs. The high-temperature oxidation modification effect is obvious. Figure 8 shows the temperature comparison curve of the oxidation front in the experiment of direct air injection and air injection after water injection. The average oxidation front temperature of the direct air injection experiment is 423.06 \({}^{\circ}\)C, and the advancing speed of the oxidation front is 268.75 mm/h. The average oxidation front temperature of the air injection experiment after water flooding is 468.51 \({}^{\circ}\)C, and the advancing speed of the oxidation front is 239.60 mm/h. As shown in Table 6, the air consumption of the 30 Mpa air injection experiment is 76.81 m\({}^{3}\)/m\({}^{3}\), and the air consumption of the air injection experiment after water injection is 91.34 m\({}^{3}\)/m\({}^{3}\). Compared with the air injection in the original reservoir, the air consumption and fuel consumption of the air injection after the water injection experiment increase, the temperature of the experimental oxidation front becomes higher, and the oxidation front is more stable. The results of air injection in heavy oil reservoirs show that the oil saturation of heavy oil reservoirs decreases after steam injection, and the in situ combustion after steam injection has the characteristics of 'limited wet burning'. Compared with the original reservoir, the temperature of the oxidation front of the heavy oil reservoir after steam injection becomes lower [22,23]. The variation law of oxidation front temperature in a high-pressure light oil reservoir with low oil saturation after water flooding exhibits a distinct pattern compared to that in a low-pressure heavy oil reservoir.