## 1 Introduction  
At present, heavy oil reserves account for more than 70% of the remaining geological reserves of petroleum in the world, which are widely distributed in the United States, Venezuela, Canada, Russia and China [1, 2]. The development of heavy oil is an effective measure to meet the increasing energy demand. At present, the CSS of horizontal wells has become one of the most widely used technologies to enhance oil recovery in heavy oil reservoirs. The development effect of the CSS of horizontal wells has had a significant impact on heavy oil production. However, after a long period of development, the CSS of horizontal wells is affected by factors such as high crude oil viscosity, high flow resistance in the horizontal section, and reducing energy formation. Most of the horizontal wells have problems, such as a poor utilization effect in the middle and back sections and in the low permeability sections, low oil production in the CSS cycle, rapid decline in oil production, the short effective production time in the cycle and low economic efficiency. Non-condensate gas-assisted CSS is a common technical method, which adopts the same injection method as non-condensate gas and steam, such as N\({}_{2}\). Due to the increase in formation pressure and the heat insulation effect of nitrogen, it can effectively increase spread effect and alleviate production decline [3, 4]. In addition to the single gas auxiliary, multi-thermal fluid-assisted CSS is also an effective mining method to improve the steam stimulation effect. The multi-thermal fluid formed by various fluid components, such as steam, CO\({}_{2}\) and N\({}_{2}\), is effective in reducing viscosity and increasing energy, reducing steam consumption and increasing the oil-steam ratio [5, 6]. However, those measures are limited to improving recovery and new technologies to improve the CSS effect need to be explored. In the past, the electric heating technology of heavy oil wells was usually used only for well heating, which has been applied in major heavy oil fields in China. Its main characteristics are low-power and low-temperature heat tracing. The power is usually 100-300 W/m and the heating temperature is about 60-90 \({}^{\circ}\)C. It can effectively improve the fluidity of high-viscosity oil in the wellbore and improve lifting efficiency, but it cannot improve the reservoir temperature near the wellbore area and reduce the flow resistance to the wellbore [7; 8; 9]. There have been some previous studies on the effects of E-CSS. Some studies indicate that electric heating reduces the viscosity near the wellbore area, increases the bottom hole pressure, and avoids the excessive release of gas near the wellbore area [10; 11]. For high-temperature and high-power electric heating technology in heavy oil wells, high power electric heating rapidly heats up the reservoir, produces micro fractures, and greatly improves porous flow capacity and oil production [12; 13]. Moreover, distributed electric heating can increase the average oil recovery rate by 30-50% and prolong the production cycle obviously [14]. Electric heating is feasible technologically and economically [15]. However, the previous research has mainly focused on downhole resistance heating to improve the uniform preheating effects of SAGD in the start-up phase, as well as the degree of usage of the horizontal section of SAGD and the scale of steam chamber development in the production phase [16; 17; 18; 19; 20]. Relevant research has not yet been carried out on the usage of E-CSS for the horizontal well. This paper suggests installing a high-energy, long-lasting and high-power resistance electrical heater into the horizontal section of the horizontal wells (the power is greater than 1000 W/m, the heating surface temperature reaches 300 \({}^{\circ}\)C, and the continuous heating time is more than 5 years), which allows for an improvement in steam enthalpy, reducing the flow resistance to wells.