Thermal management of downhole measuring tools using thermoelectric cooling : a numerical and experimental investigation

Abstract

Vertical seismic profiling (VSP) is a common geophysical technology used in oil and gas investigation in deep wells. VSP provides high resolution and dependable results but is subjected to high temperatures and harsh well environments. As these wells become deeper and hotter, the need for effective thermal management in the instrumentation becomes paramount in keeping the electronics of the measuring tool within allowable working temperatures. A highly effective and a novel technique used to cool the circuitry inside equipment is thermoelectric (Peltier) cooling. A Peltier device in a deep well measuring tool works as a heat pump. As the well is a closed environment, the understanding of the thermal behaviour inside is important in designing the tools. Thermal modelling is used for this study, but accurate modelling of the Peltier device is crucial in predicting the thermal behaviour and subsequent thermal management of the tool. Present paper is based on numerical simulations using computation fluid dynamics and experimental analysis of the thermal behaviour inside an industry standard deep well measuring tool. Present modelling results are based on two mathematical models to predict the thermal behaviour of the Peltier device. An advanced second order approximation that has been based on experimental data used to model the Peltier device is capable of producing accurate thermal predictions. Experimental validation of the model is based on measurements and is presented here. Predictions agree closely with the measurements and the model can be used as a computational tool reducing cost and time in measurements.