A transient thermal model for forecasting the real-time temperature of downhole electronics.

Logging tools are essential for high-temperature downhole oil exploration. Passive thermal management has been widely used to ensure the normal operation of downhole electronics. A key requirement for passive thermal management is the quick on-site prediction of real-time logging tool temperature. This is challenging due to variable downhole environments, initial temperature distributions, and power dissipations of heat sources. To address this issue, a transient thermal model for predicting the real-time temperature of logging tools is proposed. This model is based on a thermal network model with a discrete thermal equilibrium equation and considers heat transfer processes inside and outside the logging tool. The proposed model considers both the accuracy and the efficiency of prediction and can be applied under different working conditions. The average relative error between the proposed model and the experiment is only 6.5 %. In addition, the computing time and resources of the proposed model are significantly reduced compared with traditional numerical simulations. The proposed prediction model shows promise for wide use in real-time logging tool operations. • A real-time temperature prediction model for downhole electronics was proposed. • The accuracy of the proposed model was verified by the experiment. • The proposed model possessed high computational efficiency. [ABSTRACT FROM AUTHOR]