## 1 Introduction
It is a new multi-component thermal fluid generation method with supercritical water oxidation technology as the core and heavy oil production liquid as the material and energy source. The design and development of a supercritical multi-component thermal fluid generating device is important in supercritical multi-component thermal fluid technology. By using supercritical water oxidation (SCWO) technology, organic matter and O\({}_{2}\) will generate homogeneous reactions in supercritical water (T > 374.15 \({}^{\circ}\)C, P > 22.14 MPa), and C, H, and N in organic matter will be converted into harmless CO\({}_{2}\), H\({}_{2}\)O, and N\({}_{2}\). Heterocyclic atoms Cl, S, and P are converted into corresponding acids or salts, and a large amount of heat is released, which is mainly used in wastewater and sludge treatment. The main production methods of supercritical multi-source, multi-component thermal fluids are as follows: First, in the gasification reaction, organic waste liquid (such as diesel, gasoline, and sewage) is vaporized in the supercritical water environment to obtain gasification products such as hydrogen and supercritical CO\({}_{2}\); then, thermal fluids (supercritical water, N\({}_{2}\), and CO\({}_{2}\)) with higher temperature, pressure, and dryness are obtained by the combustion reaction of air and gasification products [21; 22; 23]. On the one hand, this preparation method effectively removes the high dependence of traditional multi-component thermal fluid on diesel oil and realizes the local use of fuel (crude oil, natural gas, etc.) for offshore heavy oil thermal recovery. On the other hand, the cost of water treatment for steam boilers and the cost of discharge treatment for oily sewage can be saved by using oily wastewater from offshore platforms [24; 25]. The heat released by the oxidation reaction in the reactor can keep the reaction temperature above the critical temperature and can greatly reduce the sewage treatment block area. The advantages of supercritical technology are shown in Table 1.  
The research on the mechanism of supercritical fluids have made some achievements in China and abroad. [PERSON] et al. [26], through laboratory core flooding experiments, found that supercritical water is more conducive to creating greater pressure differences compared to traditional steam flooding and improves the oil displacement efficiency and oil recovery speed in the initial stage of heavy oil thermal recovery. [PERSON] et al. [27] learned through experiments that the supercritical multi-component thermal fluid has both supercritical water miscible flooding and gas-assisted enhancement effects, and that the recovery rate is as high as 95%; compared with supercritical water, the thermal efficiency of the supercritical multi-component thermal fluid is increased by 16%, the produced oil viscosity of the supercritical multi-component thermal fluid is decreased by 32%, and the produced oil quality improved significantly in situ. [PERSON] et al. [28] found that supercritical N\({}_{2}\) can maintain its formation pressure and reduce heat loss by forming a gas cap, and that supercritical CO\({}_{2}\) can improve the upgrading effect of heavy oil and improve the flow capacity of heavy oil through dissolution and extraction. [PERSON] et al. [29] found through experiments that the increase in reaction temperature, pressure, and injection amount is conducive to the modification of heavy oil by supercritical gas. However, it should be noted that current research on the mechanism of supercritical technology is primarily based on laboratory evaluation experiments, with no assessment yet conducted regarding its potential application at field scale. In this paper, the Bohai heavy oil field in China was taken as the research object. Firstly, the effect of supercritical multi-source, multi-component thermal fluid flooding was evaluated through an indoor one-dimensional displacement physical simulation experiment, and the contribution mechanism of supercritical components to oil production was revealed.