Investigation of Downhole Electric Heating Efficiency in Horizontal Wells for Offshore Heavy Oil Reservoirs: A Wellbore-Reservoir Thermal Coupling Approach

High Resolution Image Download MS PowerPoint Slide Quantifying reservoir heating efficiency is crucial for evaluating downhole electrical heating technology in heavy-oil horizontal wells. To clarify heating dynamics, this study conducted physical simulations based on distributed temperature sensing (DTS) data, analyzing temperature distribution characteristics under varying heating conditions and thereby revealing corresponding patterns and systematically validating the technology’s effectiveness. Through the innovative systemic coupling of wellbore pipe flow with reservoir seepage, resolving mass–energy–heat interactions, we established a novel reservoir heating efficiency evaluation model. The model’s accuracy was verified by matching field-measured DTS data from wellbores. Sensitivity analysis further uncovered the influence of mechanisms of permeability, crude oil viscosity, liquid production rate, water cut, and heating duration on heating efficiency. Key findings include the following: (1) Reservoir temperature exhibits logarithmic decay with increasing distance from the wellbore, while effective heating radius expands significantly with higher power; (2) high liquid production rates and water cuts reduce heating efficiency through convective heat losses; (3) extended heating duration enhances electrical heating performance. Field tests confirmed that downhole electrical heating effectively mitigates near-wellbore and wellbore blockages, increasing oil production from 12 m 3 /d (cold production) to a sustained average of 45 m 3 /d. This research fills critical knowledge gaps in reservoir heating mechanisms for downhole electrical heating technology, providing vital guidance for green offshore heavy-oil development.