Thermal Optimization of a Logging Tool Used in High Temperature Downhole Environment

The logging tools suffer from thermal failure due to the high temperature downhole environment and self-generating heat of the circuits, and hence thermal management systems are usually applied to protect the inner electronics. During the system design stage, a large amount of design margin is generally reserved to ensure that the circuits do not exceed its tolerance temperature. However, the margin can be too much and leads the system overlong and overweight, which makes the operation more difficult in the downhole environment. In this paper, a logging tool with a passive thermal management system is optimized based on SOLIDWORKS/COMSOL/MATLAB co-simulation. Different optimization algorithms are utilized to get the shortest length, and thermal management performance of the system before and after optimization is compared. The results show that the coordinate search algorithm has the best effect, which can shorten the total length by 21.5% and lighten the system by 22.1%. Meanwhile, the temperature distribution is more uniform after optimization, and the average heat storage density of the phase change material is improved by 28.3%. The thermal design of the logging tool can be effectively improved through the combination of optimization algorithms and thermal simulation.