## 1 Introduction
### Experimental Apparatus  
The one-dimensional supercritical multi-source, multi-component thermal fluid displacement experimental device was independently developed, including the fluid injection system, one-dimensional supercritical multi-source, multi-component thermal fluid sand pack model, measurement and control system, and production and separation system, as shown in Figure 1. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Numbers** & **Injection Fluids** & **Injection** & **Injection** & **Water** & **N2** & **CO2** \\  & **Pressures** & **Temperatures** & **Injection Rate** & **Injection Rate** & **Injection Rate** \\ \hline
1 & steam & 10 MPa & 315 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 0 mL/min \\ \hline
2 & steam & 12 MPa & 330 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 0 mL/min \\ \hline
3 & steam & 14 MPa & 340 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 0 mL/min \\ \hline
4 & supercritical water & 23 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 0 mL/min \\ \hline
5 & supercritical water & 23 MPa & 374 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 0 mL/min \\ \hline
6 & supercritical water & 24 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 0 mL/min \\ \hline
7 & supercritical water + N2 & 23 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 2 mL/min & 0 mL/min \\ \hline
8 & supercritical water + N2 & 23 MPa & 374 \({}^{\circ}\)C & 10 mL/min & 2 mL/min & 0 mL/min \\ \hline
9 & supercritical water + N2 & 24 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 2 mL/min & 0 mL/min \\ \hline
10 & supercritical water + CO2 & 23 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 2 mL/min \\ \hline
11 & supercritical water + CO2 & 23 MPa & 374 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 2 mL/min \\ \hline
12 & supercritical water + CO2 & 24 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 0 mL/min & 2 mL/min \\ \hline
13 &
\begin{tabular}{c} Supercritical multi-source \\ multi-component thermal fluid \\ \end{tabular} & 23 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 1 mL/min & 1 mL/min \\ \hline
14 &
\begin{tabular}{c} Supercritical multi-source \\ multi-component thermal fluid \\ \end{tabular} & 23 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 2 mL/min & 2 mL/min \\ \hline
15 &
\begin{tabular}{c} Supercritical multi-source \\ multi-component thermal fluid \\ \end{tabular} & 23 MPa & 420 \({}^{\circ}\)C & 10 mL/min & 1 mL/min & 1 mL/min \\ \hline
16 &
\begin{tabular}{c} Supercritical multi-source \\ multi-component thermal fluid \\ \end{tabular} & 25 MPa & 400 \({}^{\circ}\)C & 10 mL/min & 1 mL/min & 1 mL/min \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Supercritical multi-source, multi-component thermal fluid experiment scheme. The fluid injection system includes a supercritical water generator (maximum pressure 35.0 Mpa, maximum temperature 450 \({}^{\circ}\)C), a high-pressure plunger pump, and a high-pressure intermediate vessel loaded with heavy oil, formation water, and supercritical CO\({}_{2}\) and supercritical N\({}_{2}\). Specific parameters of the experimental instruments are shown in Table 3. The supercritical water generator uses a 30 m long Hastelloy coil for heating. The first stage involves heating cold water to approximately 200 \({}^{\circ}\)C to produce wet steam, while the second stage is to heat the wet steam to about 350 \({}^{\circ}\)C dry steam, and the third stage is to further heat the dry steam to around 450 \({}^{\circ}\)C to produce superheated steam. In addition, a heat tracing device is added on to the connecting pipeline between the outlet of the supercritical water generator and the interface of the injection model to prevent loss of steam heat through the output pipeline. The sand-filled tube model is made of Hastelloy C276, the inner diameter is 3.9 cm, the length is 48 cm, and the maximum working pressure is 50 Mpa and 450 \({}^{\circ}\)C. There are six belt heaters (1500 W) on the surface of the model.