Wireless Sensor Networks (WSNs) has become increasingly important in the Oil and Gas industry. Despite the various advantages WSN has compared to the wired counter parts, it also faces some critical challenges in the oil fields; one of them is the power supply. The periodic replacement of batteries for the WSN in the downhole environments has been economically inconvenient and the enormous cost induced by the maintenance has turned people's attention to the energy harvesting technology, hoping for a more sustainable solution. Power supply is only half of the problem. To retrieve the data recorded by the various sensors in the downhole environments, a reliable way of wireless communication is required. A new approach utilizing acoustic communication was proposed. This thesis presents an Archimedean Screw Turbine (AST) based energy harvester that takes advantage of the abundant flow energy in the upper stream section of the oil production cycle, especially in the water injection wells and oil extraction wells, with the goal of providing power supply to Wireless Sensor Networks (WSNs) and underwater acoustic modems deployed in the various locations in the downhole environments. Parametric study on the number of blades, screw length, screw pitch, and rotational speed was conducted through CFD analysis using Ansys Fluent in order to determine the optimal geometry and operating conditions. The relationship between power generation and AST geometries, such as AST length and AST pitch, were discovered and the optimal rotational speed was revealed to be solely dependent on the screw pitch. Experiments were conducted in the lab environment with various flow rates and various external resistive loads to verify and determine the maximum power generation of the designed harvester. FEA analysis was conducted using the Acoustic and Structural Interaction Module of COMSOL MULTIPHYSICS to determine the attenuation characteristics of acoustic waves propagating in the water-filled pipes buried in soil. Experiments with and without the harvester integrated in the pipe system were conducted in lab environment using a pair of under water acoustic modems to determine the acoustic communication capability. The impact of the integrated harvester on the acoustic communication was tested. Combining energy harvesting technology and underwater acoustic communication together, this system can potentially achieve real-time monitoring and communication in the oil downhole environment. / Master of Science / Oil and Gas industry has been the primary energy source provider for our society for hundreds of years. As this industry evolves with new technologies, it also faces new challenges. One of the main challenges is the power supply problem in the oil field because of the limited lifespan of traditional batteries used in the oil production process. This study present a novel energy harvesting device that can replace the traditional batteries. By taking advantage of the constant fluid flow in various wells at oil field, the device can provide power for electronic devices, including but not limited to wireless sensors, communication modules, at the oil extraction sites, without needing additional power supply. This novel energy harvesting device can also be integrated with communication modules that uses acoustic wave to achieve wireless acoustic communication between underground and the surface. In this study, the harvester design, optimization, tests, and integration with acoustic modems were presented. With the help of such energy harvesting device, Oil and Gas industry will be one step closer to achieving true wireless, and real-time monitoring and communication. This will not only reduce maintenance cost but also greatly improve the production efficiency.

Le potentiel de production d'hydroélectricité à l'aide de micro centrales hydroélectriques est sous-exploité en Europe. L'exploitation de petites chutes d'eau, à l'aide des vis d'Archimède, est un moyen de production d'énergie renouvelable récent et en voie de développement. Cette thèse étudie les performances hydrauliques de ce type de turbine. Une première partie du travail a porté sur la mise en place d'un dispositif expérimental, à échelle réduite, permettant de tester pour des conditions hydrauliques et des paramètres géométriques variés les performances hydrauliques d'une vis d'Archimède. Un modèle théorique semi-analytique permettant de déterminer les performances de la vis a été développé puis validé à l'aide des résultats expérimentaux. Les écoulements complexes au sein de cette turbine sont étudiés par le biais d'une modélisation numérique 3D instationnaire, validée expérimentalement. La compréhension de la structure de l'écoulement a alors permis de développer un nouveau modèle théorique permettant de déterminer avec plus de précision le débit de fuite qui est à l'origine d'une perte significative de rendement. Ces résultats permettent d'envisager l'implémentation d'un modèle de dimensionnement industriel. / The potential for hydropower generation using micro-hydro plants is still under exploited in Europe. The Archimede Screw Generators are a growing technology convenient for low-head hydraulic sites. This thesis studies the hydraulic performance of this turbine. The first part of thiswork presents an experimental device using a laboratory screw scale. This device allows to test screw performance for various hydraulic conditions and geometrical parameters. A theoretical model predicting the screw performance has then been developed and validated with experimental results.The complex flows occurring within the screw are studied thanks to 3D and unsteady numerical simulations. The numerical results are validated experimentally. The insights provided on the flow structure permit to develop a new leakage model. These leakages are a major source of efficiency loss. Eventually, all these results will allow the implementation of an industrial dimensioning model.

La R.D. Congo possède l’un de taux de desserte en électricité le plus faible au monde (moins de 1 % en zones rurales) malgré son important potentiel hydroélectrique estimé à 100.000 MW. Pour accroitre le taux de desserte en électricité en construisant des microcentrales hydroélectrique, il est impérieux d’utiliser une technologie simple, fiable, robuste et peu coûteuse. La turbine à vis d’Archimède apparait comme une solution appropriée à ces exigences. Nous avons ainsi conçu et fabriqué localement (à Lubumbashi) un banc d’essai d’une turbine à vis d’Archimède possédant seulement deux hélices et des pas larges (β = 30° et β = 45°). L’objectif étant de simplifier la fabrication et réduire la quantité d’acier utilisé pour la vis par rapport aux vis utilisées en Europe et aux U.S.A. Le banc d’essais nous a permis d’obtenir six configurations combinant la pente de la vis (α = 22,5°, 30° et 37,5°) et les pas. La combinaison la plus optimale est la configuration de la vis inclinée de α = 22,5° par rapport à l’horizontale et dont l’hélice est orientée de β = 45° sur le moyeu (p45H22).<p>En second lieu, vient la configuration de la vis inclinée de α = 30° et dont l’hélice est orientée de β = 45° sur le moyeu (p45H30). Ces deux configurations ont respectivement un rendement à débit nominal de 89 et 86 %./D.R. Congo has an electricity service rate that ranks as the lowest in the world (less than 1% in rural areas) despite its large hydroelectric potential estimated at 100,000 MW. To increase the rate of access to electricity by constructing small hydropower plant, it is imperative to use simple technology, reliable, robust and inexpensive. The Archimedean screw turbine appears to be an appropriate solution to these requirements. We have designed and manufactured locally (in Lubumbashi) a test bench for Archimedean’s screw turbines having two blades only and a large pitch p function of β ( β = 30 ° and β = 45 °, β being the orientation angle of the blade on the screw cylinder). The goal is to simplify manufacturing and reduce the amount of steel used for the screw relative to the screws used in Europe or in USA. The test bench has allowed the experiments with six configurations combining the slope of the screw (α = 22.5 °, 30 ° and 37.5 °) and the pitch p (with varying rotation speed). The optimal combination appeared to be the configuration of the screw inclined at α = 22.5 ° relative to the horizon and with an helix β = 45 ° on the cylinder of the screw. The second best configuration has an inclined screw α = 30 ° and the helix which is oriented β = 45 °. These two configurations each have a global efficiency of 89% and 86%, respectively. <p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished