Numerical simulation of thermal fluid-assisted electric heating for enhanced reservoir temperature

ABSTRACT In-situ conversion processing (ICP) holds significant promise for unconventional resource development. While electric heating (EH) and steam injection are relatively mature heating technologies, challenges remain regarding low heating efficiency and high wellbore temperatures. To address these limitations, this study proposes a thermal fluid-assisted electric heating (TFAEH) method to enhance reservoir heating rate and production performance. A non-isothermal heat transfer mathematical model, coupled with the velocity and temperature fields, was developed to simulate the heat transfer process. The model was validated using temperature data from the physical experiments. An intermittent fluid injection heating strategy was then adopted to optimize fluid flow. Finally, the characteristics of EH and TFAEH were comprehensively compared based on reservoir temperature distribution, oil production, and energy conversion. Results demonstrate that TFAEH significantly outperforms EH in terms of heating efficiency, production performance, and energy consumption. Specifically, after 500 days of heating, the heated area increased by 22.13%, and the thermal sweep volume above 350°C increased from 1.65% to 4.07%. The maximum daily production was achieved 117 days earlier, with a 134.53% increase in peak daily oil production and a 44.55% increase in total oil production. Furthermore, the energy utilization rate improved by 44.29%. The proposed intermittent fluid injection heating strategy effectively mitigates the issue of high wellbore temperatures.