Rapid technological advancements and growing environmental consciousness created a shifting dynamic of metal demand within the context of contemporary global challenges. The metals play a pivotal role in this transformation and remarkable surge in demand is expected. Mining districts such as the Kiruna area in northern Sweden, provide access to raw materials, assuring supply chain security, sustainability, and an environmentally friendly future. The district is part of the northern Norrbotten ore province, Sweden and is known for hosting the Kiruna-type iron oxide-apatite (IOA) deposits with associated magnetite-hematite-REE ores such as the Per Geijer deposits, and a range of other deposits, including the Viscaria Cu-(Fe-Zn), Pahtohavare Cu-Au and the Rakkurijärvi iron oxide-copper-gold (IOCG) deposits.  As the discoveries of significant near-surface deposits are declining, mining companies face a pivotal choice between pursuing resource extraction from lower-grade reserves or to focus on deeper exploration targets. The geological understanding of the subsurface decreases with increasing depth, and the reliance on geophysical techniques becomes more important in reducing the search space. Using geophysics to locate and understand elements of a mineral system requires a good understanding of the physical and chemical properties of the rocks that can be translated into geological implications. Mineral system knowledge and geological concepts can be translated into geological models that can be further used in geophysical inversions with the aim of improving targeting by iterative modeling. A geophysical inversion is in fact a realization of a physical property model, therefore the value added by the geophysical model is dependent of how well the relationship between the geology and its petrophysical signature is understood. The petrophysical characterization of geological environments offers the possibility to improve the understanding of geophysical responses, serving as a link in iterative geological-geophysical modeling.  The approach presented in the current study includes the building of three-dimensional lithological and structural framework models, and investigating the petrophysical footprint in connection with lithology, alteration, and rock fabric from the Kiruna mining district. Geological modeling and petrophysical characterization are important components within the comprehensive mineral system modeling framework and enhance geophysical investigations aimed at detecting and assessing iron oxide mineral systems. A rule-based hybrid implicit-explicit geological modeling technique proved to be useful in the integration of surface and subsurface data of the Kiruna mining district, and a structural framework and geological model was produced that provides insights into the relationship between lithological units and structures. Drill core observations indicate a competency contrast between lithological units confirming previous surface-based observations. Deposit scale structural analysis in connection with the geological models indicated the proximity of NW-SE to SW-NE trending brittle conjugate fault networks with iron-oxide apatite ore lenses, revealing juxtaposition of individual ore lenses. Complementing structural analysis and geological modeling, petrophysical characterization in connection with lithogeochemical, mineralogical, and textural investigations revealed that density and p-wave seismic velocity can be used as a general lithological indicator, while magnetic susceptibility is influenced by secondary processes. Heterogeneous strain accommodation by lithological units indicates a strong influence on density, seismic properties, and the ferromagnetic properties of the samples. Metasomatic processes alter the intrinsic properties of the samples by increasing or decreasing the physical properties of the rocks from the Kiruna area, by controlling the feldspar, mica, magnetite, and ferromagnesian mineral content. Nevertheless, an extensive sample population must be investigated to understand the large-scale effects. The present work serves as a foundation for quantitatively integrated exploration models that use geological models and petrophysical characterization as calibration tools to model mineral systems.

La compréhension d'un système pétrolier nécessite la caractérisation pétrographique de tous les éléments et les processus le composant. Dans ce travail, plusieurs exemples de roches mères, roches réservoirs et roches couvertures provenant de bassins pétroliers différents, ont été étudiés afin de décrire les méthodes pétrographique classiques et mettre en place des nouvelles. Ces dernières telles que : la création d'une cinétique de transformation d'un kérogène composé de deux types de matière organiques (programmation), analyse macérale et l'étude des microfractures par analyse d'images, la diffraction à rayon X ainsi que la tomographie ont permis la caractérisation de la roche mère. Quant aux roches réservoirs, les méthodes d'analyse d'image des propriétés pétrophysiques, la microscopie MSCL ainsi que les paramètres de mouillabilité permettent la description de la qualité de ces réservoirs et leurs préservations au cours du temps à cause des phénomènes de recristallisation, dissolution, circulation de fluide et de réaction TSR/BSR. Les roches couvertures étudiées dans ce travail sont celles des argilites callovo-oxfordienne, utilisant la diffraction à rayon X ainsi que l'analyse d'image et la tomographie. Ces méthodes ont facilité la compréhension de leurs comportements au cours du temps, leurs capacités de sorption/désorption et leurs fiabilités de stockage de déchets nucléaire. Enfin, la modélisation pétrolière avec Petromod permet de déterminer les fonctionnements des systèmes pétroliers. La modélisation par percolation est plus proche de la réalité des bassins pétroliers que celle de Darcy/Hybride / Understanding oil systems requires petrographic characterization of all elements and process that compose it. In this work, several examples of source rocks, reservoir rocks and seal from different petroleum basins have been studied in order to describe conventional petrographic methods and develop new ones. The new ones as: a program of transformation kinetic of kerogene composed of two types of organic matter, maceral analysis and microfractures study using images analysis, the diffraction X-ray and tomography allowed source rock description. As for, reservoir rocks, methods of petrophysical characterization by images analysis, MSCL Microscopy and wettability parameters permit reservoir quality description and their preservation over time due to recrystalization and dissolution phenomena, fluid flow and TSR/BSR reaction. The cap rocks studied in this thesis are those of Callovo-Ordovician argillites, using X-Ray diffraction as well as images analysis and tomography. Those methods facilitated the understanding of argillites behavior over time, their sorption/desorption ability and their reliability of nuclear waste storage. Finally, Modeling using Petromod helps to determine petroleum systems functioning. Modeling by percolation method gives results closer to oil basins reality, than by Darcy/Hybrid method