## 1 Introduction
### Experimental Results and Discussion  
Currently, the percolation characteristics, production effect, and temperature and pressure distribution in supercritical multi-source, multi-component thermal fluid flooding are still unclear. Therefore, further analysis of the displacement characteristics of supercritical multi-source, multi-component thermal fluid was conducted through Experiment 13. In Experiment 13, a total of 4 PV (pore volume) supercritical multi-source, multi-component thermal fluids were injected. The experimental temperature distribution, pressure difference, and production curve are illustrated in Figures 2-4. As shown in Figure 2, the supercritical multi-source, multi-component thermal fluid displacement process can be delineated into three stages. During the initial phase of displacement (0-1.1 PV), upon injection, the temperature at measuring points TC1 to TC4 near the inlet rose rapidly. It is noteworthy that TC1's temperature gradually increased, reaching 400 \({}^{\circ}\)C at this stage. The temperatures of the three measuring points on vertical plane 1 (Figure 3) were essentially identical, indicating uniform heating (with TC1 registering the highest temperature) due to rapid vertical heat transfer resulting from high injection temperature and a small vertical area. At this stage, the supercritical multi-source, multi-component thermal fluid significantly augmented the flow capacity of heavy oil near the inlet. However, despite this enhancement, the model's exit temperature remained relatively low, leading to low oil flow capacity at the outlet and consequently causing a sharp increase in the inlet-outlet pressure differential during this stage (Figure 4). Figure 2: Relationship between temperature and injection volume at each point in the model axis. In the middle stage of displacement (1.1-1.5 PV), with the continuous injection of supercritical multi-source, multi-component thermal fluid, the heating range gradually expanded, and the heating front basically reached the exit of the sand-filled model. There  
Figure 4: Comparison of pressure difference (**a**) and recovery efficiency (**b**). Figure 3: Relationship between temperature and injection volume at inlet face (**upper left**); mid face (**upper right**) and outlet face (**down**). fore, the temperature of TC1-TC3 measuring points reached 400 \({}^{\circ}\)C, and the temperature of TC4-TC7 measuring points began to rise (Figure 2). At this time, the heavy oil flow capacity increased and consequently, the heavy oil displacement efficiency began to rise rapidly. Vertical surfaces 1 and 4 exhibited a uniform temperature distribution (Figure 3). However, in vertical plane 7, there was non-uniformity in temperature distribution where T\({}_{\text{T7}}\) was higher than T\({}_{\text{B7}}\). The reason for this phenomenon may be that the supercritical multi-source, multi-component thermal fluid produces the overlap phenomenon, and a small amount of supercritical multi-source, multi-component thermal fluid moves to the top of the sand-filled model due to the action of gravity. In the late displacement stage (1.4-5.0 PV), the maximum heating range was achieved, with the temperature at each measuring point reaching 400 \({}^{\circ}\)C (Figures 2 and 3) After the breakthrough of the supercritical multi-source, multi-component thermal fluid, the pressure difference of the inlet and outlet was basically stable, and the cumulative gas production increased sharply. Consequently, the growth rate of oil displacement efficiency in this stage slowed down. The above reasons indicate that supercritical multi-source, multi-component thermal fluid breakthrough has adverse effects on heavy oil production. As illustrated in Figure 4 and Table 4, the displacement efficiency reached as high as 85.15% when the injection volume of supercritical multi-source, multi-component thermal fluid reached the end of 4 PV.