A study on PDC drill bits quality

The quality of innovating PDC (Polycrystalline Diamond Compact) bits materials needs to be determined with accuracy by measuring cutting efficiency and wear rate, both related to the overall mechanical properties. An original approach is developed to encompass cutting efficiency and wear contribution to the overall sample quality. Therefore, a lathe-type test device was used to abrade specific samples from various manufacturers. Post-experiment analyzes are based on models establishing coupled relationships between cutting and friction stresses related to the drag bits excavation mechanism. These models are implemented in order to evaluate cutting efficiency and to estimate wear of the diamond insert. Phase analysis by XRD and finite element simulations were performed to explain the role of physicochemical parameters on the calculated quality factor values. Four main properties of PDC material were studied to explain quality results obtained in this study: cobalt content in samples that characterizes hardness/fracture toughness compromise, undesired phase as tungsten carbide weakening diamond structure, diamond grains sizes and residual stresses distribution affecting abrasion resistance

Functionally graded cemented carbides elaboration by imbibition process—Better understanding of liquid migration and homogenization mechanisms for an improved process

International audienceCemented carbides are used in rock drilling, for mining tools and other wear-resistant parts. These composite materials possess an excellent compromise between hardness and toughness. Currently, the concept of graded structure (FGM) is widely studied to improve these two properties simultaneously, and thus to increase the service life of drilling tools. This paper focuses on the imbibition process. The imbibition process gradually enriches the core of dense cemented carbide with binder phase and is based on the principle of liquid-phase migration in a solid/liquid body. FGM generated by such techniques shows interesting mechanical properties gradient, such as 400 HV on 20 mm hardness gradient. Hardness gradient development is achieved through a better understanding of kinetics and other phenomena occurring during imbibition. The goal is to select suitable process parameter for each grade of carbide

Solution de valorisation des résultats, de l’expertise et du partenariat du projet de recherche GEOTREF: vers un réseau pluridisciplinaire ouvert, coordonné et supervisé d’entreprises et de laboratoires hautement spécialisés en géosciences

International audienceUnder the pressure of climate change and the transition to low-carbon energy, geothermal energy is experiencing an unprecedented worldwide craze. Investors are mobilizing, oil companies are interested in it and many companies are being created to propose solutions likely to facilitate or improve its exploitation. However, the risks associated with the resource (underground uncertainties) remain a major obstacle to its development, whatever the mode of exploitation and use (electricity, heat). The risks are all the more complex to assess as they can be short-term (absence of an economically exploitable resource after drilling) or longterm (depletion of the resource that has become economically unprofitable). The observation is unanimous: to remove the risks and better exploit the resources, it is necessary to implement fully multidisciplinary, collaborative approaches with a high level of expertise in geoscience. This expertise exists and continues to grow, but in a dispersed manner and with little or no synergy, in research laboratories and in highly specialized companies. They are rightly absent in companies that develop geothermal energy and whose primary vocation is to exploit well identified resources in the long term, not to understand and conceptualize the operation in all its complexity with the associated uncertainties. The GEOTREF R&D project, financed by Investissements d'Avenir and ADEME, has been designed to cover all the fields of expertise required in geoscience and modelling in order to better address the risks associated with the geothermal resource by integrating the issue of fractured reservoirs. This project involves highly specialized universities and companies. It has helped to acquire new knowledge in geothermal energy, to develop innovative methods and approaches, to develop a software platform dedicated to geothermal energy and to create real synergies between the partners. The paper will present the solution being prepared by GEOTREF to provide all the services necessary for the identification, reliable assessment and sustainable exploitation of geothermal resources: data acquisition, processing and interpretation, collaborative multidisciplinary expertise in geoscience, formalization and parameterization of uncertainties, production of static and dynamic models integrating data, assumptions and interpretations, production of decision support elements useful at all stages of a project. The solution is based on an open network of companies and laboratories, coordinated and supervised by a start-up company in preparation. The target market is international.Sous la pression du changement climatique et de la transition vers une énergie décarbonée, la géothermie connaît un engouement mondial sans précédent. Des investisseurs se mobilisent, des pétroliers s’y intéressent et de nombreuses sociétés se créent pour proposer des solutions susceptibles d’en faciliter ou d’en améliorer l’exploitation. Les risques liés à la ressource (incertitudes souterraines) restent cependant un frein majeur à son développement quel qu’en soit le mode d’exploitation et l’usage (électricité, chaleur). Les risques sont d’autant plus complexes à évaluer qu’ils peuvent être à court terme (absence d’une ressource économiquement exploitable après forage) ou à long terme (épuisement de la ressource devenue non rentable économiquement). Le constat est unanime : pour lever les risques et mieux exploiter les ressources il faut mettre en oeuvre des approches pleinement pluridisciplinaires, collaboratives et d’un haut niveau d’expertise en géosciences. Ces expertises existent et continuent de s’enrichir mais de façon dispersée et sans synergie ou très peu, dans des laboratoires de recherche et dans des entreprises hautement spécialisées. Elles sont absentes à juste titre dans les entreprises qui développent la géothermie et dont la vocation première est d’exploiter durablement des ressources bien identifiées, pas d’en comprendre et d’en conceptualiser le fonctionnement dans toute sa complexité avec les incertitudes associées. Le projet R&D GEOTREF financé par les Investissements d’Avenir et l’ADEME a été conçu justement pour couvrir tous les domaines d’expertise nécessaires en géosciences et en modélisation pour lever au mieux les risques liés à la ressource géothermique en y intégrant la problématique des réservoirs fracturés. Ce projet implique des universités et des entreprises hautement spécialisées. Il a permis d’acquérir des connaissances nouvelles dans la géothermie, de développer des méthodes et approches innovantes, de développer une plateforme logicielle dédiée à la géothermie et de créer de véritables synergies entre les partenaires. La communication présentera la solution en cours de préparation issue de GEOTREF pour apporter tous les services nécessaires à l’identification, l’évaluation fiable et l’exploitation durable de ressources géothermiques : acquisition, traitement et interprétation des données, expertise pluridisciplinaire collaborative en géosciences, formalisation et paramétrisation des incertitudes, production de modèles statiques et dynamiques intégrant données, hypothèses et interprétations, production d’éléments d’aide à la décision utiles à tous les stades d’un projet. La solution repose sur un réseau qui se veut ouvert d’entreprises et de laboratoires, le tout coordonné et supervisé par une start-up en préparation. Le marché visé est à l’international