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International audience; By conducting both a bottle test and isolate drop−drop experiments, we determine the coalescence rates of water droplets within water-in-oil emulsions stabilized by a large amount of Span 80 in the presence of Tween 20, a surfactant that acts as a demulsifier. Using a microscopic model based on a theory of hole nucleation, we establish an analytical formula that quantitatively predicts the coalescence frequency per unit area of droplets whose interfaces are fully covered by surfactant molecules. Despite its simplicity and the strong assumptions made for its derivation, this formula captures our experimental findings on Span 80stabilized emulsions as well as other results, found in the literature, remarkably well on a wide range of water-in-crude oil systems.

National audience; Les connaissances acquises sur l’exhumation de la chaine Pyrénéenne et l’évolution desbassins d’avant-pays adjacents permettent à présent d’appréhender ce systèmeorogénique complexe dans une démarche intégrative dans l’espace et le temps.Cette approche, dite « source-to-sink » s’attache à comprendre l’évolution du routagesédimentaire depuis la Source (relief orogénique, craton, recyclage de bassin) enpassant par la zone de transfert (périphériques ou internes au bassin) jusqu’au réservoirfinal (bassin flexural, bassin turbiditique profond). Nous proposons, dans le cadre decette nouvelle cartographie, de compiler les données disponibles et nouvellementacquises dans le projet, sur l’ensemble du domaine péri-pyrénéen du Golfe du Lion àl’Est jusqu’au Golfe de Gascogne à l’Ouest en incluant le Massif Armoricain au Nordjusqu’au bassin de Madrid au Sud.La réalisation de ces cartes s’appuie sur l’utilisation de nombreuses méthodes et outils,tels que les reconstructions cinématiques du système Ibérie-Europe-Méditerranée, lescoupes restaurées, l’histoire d’exhumation par thermochronologie, le traçage dessources, la caractérisation des surfaces d’altération et d’érosion, la synthèse de l’activitédes accidents structuraux majeurs, les reconstructions paléogéographiques, l’analyse desgéométries sédimentaires et des directions de transport ainsi que la quantification desvolumes préservés dans les bassins.Les pas de temps choisis pour ces cartes permettent de rendre compte de différentsstades d’évolution tectono-sédimentaire du système péri-pyrénéen au stade dequiescence de l’orogenèse (1) à 65 Ma, Danien, et aux stades précoces de l’orogenèse(2) Thanétien terminal (56Ma) et (3) Yprésien (52 Ma). Les compilations effectuéesmettent en regard domaines exhumés et zone de sédimentation en termes de flux et devolumes, et permettent de cartographier les systèmes de routage et leur évolution aucours d’un cycle de construction d’un orogène.Travaux de recherche financés et réalisés dans le cadre du programme BRGM-TOTALSource-to-Sink

International audience; This brief review focuses on the use of optical remote sensing for oil prospecting and monitoring in vegetated regions. Major advances have been achieved in this field during the last decade. Recent studies demonstrated that oil can be detected and quantified by exploiting vegetation reflectance from airborne-and satellite-embedded sensors. Various methods coupling vegetation indices or radiative transfer models with classification or regression algorithms have been proposed for this purpose. High spatial and spectral resolutions greatly increase the accuracy of oil detection and quantification. However, important limits remain in regions with sparse or highly diversified vegetation. Oil spills become also more difficult to map when other environmental stressors occur. Hence, an important effort remains to move toward operational applications, especially on upcoming drone-and satellite-embedded hyperspectral sensors.

National audience; L’objective est de présenter des résultats préliminaires des tests de cristallisation d’hydrate de gaz dans la boucle Archimède, après l’installation des capteurs d’émission acoustique et de permissivité. Les résultats montrent qu’il est possible de suivre les particules d’hydrate et d’identifier les dépôts sur les parois et/ou les accumulations d’hydrate spécifiques le long du pipeline, identifier la phase continue et détecter l'inversion de phase dans certaines conditions. Avec ces résultats, nous attendons à pouvoir caractériser le modèle d'écoulement avant et après la formation d'hydrate et à classer la sévérité de la formation d'hydrate en fonction des géométries d'écoulement observés. - La formation d'hydrates de gaz peux poser un problème de production dans certaines conduites pétrolières. Les inhibiteurs thermodynamiques d'hydrate (THIs) et les inhibiteur d'hydrates à faible dosage (LDHIs) qui comprennent les inhibiteurs cinétiques (KHIs) et anti-agglomérants (AAs) sont les additifs habituellement utilisés par l'industrie pour éviter la formation de bouchons d'hydrate. Les THIs et les LDHIs ont des avantages et des inconvénients. Les additifs LDHI-AA sont censés réduire la taille des particules d'hydrate et empêcher ou limiter leur agglomération. De nombreux travaux dans la littérature ont montré que les LDHI-AAs réduisent le blocage pour les systèmes à faible fraction d’eau, mais qu'ils ne sont apparemment pas très efficaces dans les scénarios à fortes fractions d'eau.Le présent travail a pour but de mieux comprendre la formation d’hydrates dans les pipelines par le biais d’une étude expérimentale sur la formation d’hydrates de gaz dans un circuit en boucle se concentrant sur les systèmes à fort pourcentage d’eau avec et sans AA. Les tests sont réalisés dans la boucle Archimède à l’école des Mines de Saint-Etienne ([1] et [2]) avec gaz naturel, eau et l’huile Kerdane. La boucle est composé par un pipeline de 50 mètres, avec des sections horizontales, ascendantes et descendantes. Il est équipé d'un système de refroidissement, de sondes de perte de charge et de température. Il est possible de travailler avec une pression absolue allant jusqu'à 75 bars. Le système comporte également une mesure de réflectance du faisceau focalisé (FBRM) et un mesurage vidéo de particules (PVM). Les améliorations récentes de l'instrumentation comprennent l'installation de sondes à émission acoustique pour suivre la formation d'hydrates, l'agglomération et les dépôts.Les résultats préliminaires montrent qu’avec l’émission acoustique, la distribution de la longueur des cordes et la mesure de la perte de charge, il est possible de suivre les particules d’hydrate et d’identifier les dépôts sur les parois et/ou les accumulations d’hydrate spécifiques le long du pipeline. Une autre amélioration du pilote expérimental a été l'installation d'une sonde de permittivité, qui aide à identifier la phase continue et à détecter l'inversion de phase dans certaines conditions après le début de la cristallisation. Avec les sondes d'émission acoustique et de permittivité, nous nous attendons à pouvoir caractériser le modèle d'écoulement avant et après la formation d'hydrate et à classer la sévérité de la formation d'hydrate en fonction des modèles d'écoulement observés.[1] Melchuna, A., Cameirao, A., Herri, J-M., Glenat, P. Topological modelling of methane hydrate crystallization from low to high water cut emulsion systems. Fluid Phase Equilibria, Vol. 413, pp. 158 – 169 (2016).[2] Pham, T.K. Experimental study and modelling on methane hydrates crystallization under flow from a water-oil dispersion at high water cut. PhD Thesis, 334 p., Mines Saint Etienne, France (2018).

International audience; Mixed Clathrate hydrates are an important issue in many fields, like flow assurance in the oil industry, as well as gas capture and storage, air conditioning, etc…Usually, studies of gas hydrates from hydrocarbon gas mixtures do not mention the volume of hydrate, nor the hydrate composition, and ternary or quaternary mixtures are not considered. Also, data involving propane and butane are limited.Therefore, we suggest both an experimental and modeling study of mixed clathrate hydrates from N2-CO2-CH4-C2H6-C3H8-C4H10 gas mixtures, in temperature range of [0.8-19°C] and pressure range of [1.4 – 66bars]. The experimental work provides 78 equilibrium points. Two procedures were used to perform crystallizations. The main procedure (71 equilibrium data) corresponds to a method at high crystallization rate (high supersaturation, or high ΔP). The first objective is to study the gas hydrates formation in usual dynamic conditions (start-up or reboot of an oil exploitation). The second method, 7 data, corresponds to a low rate of crystallization. This second objective is to investigate the impact of the speed of crystallization on the final equilibrium. For both procedures, P-T data are given, as well as the compositions of each phase at equilibrium.At last, thermodynamic modeling is used to compare the experimental results of both procedures. Kihara parameters of N2, CO2 and CH4 are taken from the literature, while parameters for C2H6 are regressed and given in this work.Results show a better agreement of the thermodynamic modeling with experimental study for pure gas hydrate and mixed gas hydrates at low crystallization rate. This observation suggests that mixed gas hydrates might form at thermodynamic equilibrium only at low crystallization rate.

National audience; The formation of gas hydrates in oil and gas pipelines has developed into a hazardous problem, since it may cause the plugging of the pipeline. Recent studies have shown that coupling multiphase flow and gas hydrate formation is necessary in order to predict plugging tendencies (Ding et al., 2017; Joshi et al., 2013; Melchuna et al., 2016; Pham, 2018). The flow pattern before hydrate formation affects the hydrate formation rate, since the hydrate formation requires the contact between water and gas. The droplets sizes present on the flow will directly interfere on the initial size of the particles. The flow pattern after hydrate formation plays a decisive role on whether the plugging will be observed or not. Three important phenomena in solid-liquid flow are agglomeration, deposition and sedimentation of particles. Agglomeration occurs when two particles collide and adhere each other due to the attractive forces and growth near the contact between them. It directly affects the size of the dispersed particles. The larger are the particles flowing in the pipeline, the higher is the risk of plugging. Deposition occurs due to the collision of the particles to the wall and other phenomena. Sedimentation of particles at the bottom or at the top of the pipeline takes place when the flow velocity is not enough to carry the particles. When deposition or sedimentation occur, the cross sectional area is reduced, affecting the flow rate and the pressure drop, which increases the risk of plugging. The biggest challenge is to understand how these three phenomena will occur over time and space. The objective of this work is to analyze the mechanisms observed in agglomeration, deposition and sedimentation of particles, investigate how they behave according to the flow initial conditions, and see if it is possible to stablish a relationship between the observed flow patterns and the plugging risk. An experimental work will be conducted to simulate hydrate formation using a flow loop (Melchuna et al., 2016), applying high pressure and low temperature similar to the ones found in deep sea. A range of water cut with different flow rates will be tested. A commercial anti-agglomerant and salt will be tested as well to evaluate if they reduce the risk of plugging.; La formation d'hydrates de gaz dans les oléoducs et les gazoducs est devenue un problème dangereux, car elle peut provoquer le bouchage des pipelines. L'objectif de ce travail est d'analyser les mécanismes d'agglomération, de dépôt et de sédimentation des particules, en fonction des conditions initiales d'écoulement. Un travail expérimental sera mené pour former les hydrates en utilisant une boucle d'écoulement à haute pression et basse température. Une gamme de fractions d'eau avec des différents débits sera testée. Un additif antiagglomérant et du sel seront également testés pour évaluer s'ils réduisent le risque de bouchage.

International audience; Experimental studies on flow loop allow estimating the amount of formed hydrate and their transport during time. The amount of hydrates formed spatially during flow is unknown together with the location of the beginning of sedimentation and plug. This experimental study was carried on to verify the use of acoustic emission (AE) to spatially follow the formation of hydrates but also sedimentation and agglomeration. The AE energy variations allowed to follow the emulsification, to identify the beginning of the crystallization and to follow the crystallization, agglomeration and plug/sedimentation in the flow loop.

International audience; The syndioselective copolymerization of styrene with ethylene (in bulk or in aliphatic hydrocarbon solutions, (nBu)2Mg as scavenger, Tpolym = 60-140 °C) was achieved in the presence of a series of ansa-lanthanidocenes of the type {R2C(C5H4)(R′R′Flu)}Ln(1,3-C3H3(SiMe3)2)(THF)x (1-Nd-K-allyl, 2-7-Nd, and 2-Sc,La,Sm,Pr). While precursors based on small ionic radius metals (2-Sc) or bearing bulky substituents in 3,6-positions of the fluorenyl moieties (3-Nd and 5-Nd) were poorly or not active under standard polymerization conditions (60 °C), 2-La,Pr,Nd,Sm which bear 2,7-tBu2 substituents on the Flu ligand produced efficiently sPSE materials (productivity 300-400+ kg mol(Ln)-1 h-1, [r]5 = 71%; controlled amount of ethylene inserted in the range 1-15 mol %). Under harsher conditions (Tpolym = 100-140 °C, [St]0/[Nd]0 = 40 000-147 000 equiv), 2-Nd produced similar sPSE materials with a productivity increased by 1 order of magnitude (up to 5430 kg mol(Nd)-1 h-1). Theoretical DFT investigations including the solvent model, performed on the first three insertion steps for the benchmark catalysts {(Me2C(C5H4)(Flu)}Nd(C3H5)(THF) (I), the putative 1-Nd, and the most effective 2-Nd, allowed to corroborate the nature of the obtained copolymers, with ethylene units randomly distributed within long sPS sequences. These studies established also that the presence of bulky substituents on the fluorenyl ligands is crucial in the activity, but the nature of the substituents on the allyl group has no effect on the chemistry and the nature of the resulting styrene-ethylene copolymer but only influences the initiation step in which the first ethylene insertion will be more or less favored with respect to the styrene insertion.

International audience; We hypothesize that traces of thematic activities present in the scientific productions of a company (the case of TotalEnergies) are useful for the social development of a company in full mutation. We present a new approach allowing us to identify these traces by using a cartography that shows the organization of the company, and by conducting interviews with the researchers and the communicators. This will then allow us to build a first ontology skeleton as recommended by the SAMOD methodology. Finally, we will detect and analyze traces in the scientific documentary corpus.; Nous faisons l'hypothèse que des traces d'activités thématiques présentes dans les productions scientifiques d'une entreprise (le cas de TotalEnergies) sont utiles à des fins de développement social d'une entreprise en pleine mutation. Nous présentons une nouvelle approche permettant d'identifier ces traces par l'exploitation d'une cartographie qui fait état de l'organisation de l'entreprise, la mise en oeuvre d'entretiens avec les chercheurs et les communicants. Cela nous permettra ensuite de construire un premier squelette d'ontologie comme le préconise la méthodologie SAMOD. Enfin, nous détecterons et analyserons des traces dans les corpus documentaires scientifiques.

GasHyDyn : Logiciel de simulation de la composition et de la stabilité des hydrates de gaz; National audience; Offshore systems mainly containing crude oil, natural gas and water operate at low temperature and high pressure which favour conditions for gas hydrate formation and agglomeration. Gas hydrate is a serious issue in flow assurance; it may cause many troubles, especially, plugging in oil and gas pipeline. This work is to intend to develop a kinetic model to predict gas hydrate formation, agglomeration and plugging in flowlines based on the experimental data obtained from Archimede Flowloop from the work of Mendes-Melchuna (2015). In this model, the mean droplet size of emulsion will be calculated from flow parameters to evaluate the surface area of droplets which are very critical parameters for kinetic model of gas hydrate formation in emulsion. It is important to note that anti-agglomerants (AAs) may modify the water-oil interfacial tension leading to smaller mean droplet size. A preliminary study of the emulsion formation and behaviour will contribute to a better understanding of the hydrates formation and agglomeration.

Mechanisms driving cyclicity in the marine realm during hothouse climate periods in response to Earth’s orbit variations remains debated. Orbital cycles fingerprint in the oceanographic records results from the effect of terrestrial (eg. weathering-derived nutrient supply, freshwater discharge) and oceanic (eg. productivity, oxygenation) processes, whose respective contribution remains to be defined. Here we investigate the effect of extreme orbital configurations on oxygenation state of the ocean using ocean biogeochemistry simulations with the IPSL-CM5A2 Earth System Model under (CT) Cenomanian-Turonian boundary conditions. We also use an additional inert artificial tracer allowing to compute the age of water masses, corresponding to the time spent since the last contact with the surface. Our simulations show that small ocean ventilation changes triggered by orbitally-induced variations in high latitude deep water formation have strong impact on the oceanic oxygen spatial distribution. It is particularly true for the proto-Atlantic basin which is the less oxygenated basin during the CT (Laugie et al., 2021). The eight sets of orbital parameters tested here imply changes in the Atlantic anoxic seafloor area going from 20 to 80%. All three parameters describing the Earth’s orbit (eccentricity, precession and obliquity) show a substantial control on these fluctuations. We also note that orbital fluctuations result in important changes in continental runoff but the impact remains highly localized to coastal environments – the open ocean mainly responding to the ocean ventilation. Last but not least, changes in productivity induced by the orbital parameters remain spatially heterogeneous and could be responsible for more local signal within a single basin. Laugié, M., Donnadieu, Y., Ladant, J. B., Bopp, L., Ethé, C., & Raisson, F. (2021). Exploring the impact of Cenomanian paleogeography and marine gateways on oceanic oxygen. Paleoceanography and Paleoclimatology, 36(7):e2020PA004202.

Detection of Zn(II) in oil-polluted seawater via square-wave anodic stripping voltammetry (SW-ASV) utilizing thin gold electrodes sputtered onto nanoporous poly(acrylic acid)-grafted-poly(vinylidene difluoride) (PAA-g-PVDF) membrane is herein reported. Prior to SW-ASV, PAA grafted nanopores demonstrated to efficiently trap Zn(II) ions at open circuit. This passive adsorption followed a Langmuir law. An affinity constant of 1.41 L $$\upmu $$ μ mol$$^{-1}$$ - 1 and a maximum Zn(II) adsorbed mass q$$_{max}$$ max of 1.21 $$\upmu $$ μ mol g$$^{-1}$$ - 1 were found. Applied SW-ASV protocol implied an accumulation step (− 1.2 V for 120 s) followed by a stripping step (− 1.2 to 1 V; 25 Hz; step: 4 mV; amplitude: 25 mV; acetate buffer (pH 5.5)). It revealed a Zn redox potential at − 0.8 V (Ag/AgCl pseudo-reference). Multiple measurements in synthetic waters close to the composition of production waters exhibited a decreasing precision with the number of readings R (1.65$$\%$$ % (R = 2) and 6.56$$\%$$ % (R = 3)). These membrane-electrodes should be used as disposable. The intra-batch mean precision was 14$$\%$$ % (n = 3) while inter-batches precision was 20$$\%$$ % (n = 15). Linear and linear-log calibrations allow exploitation of Zn(II) concentrations ranging from 10 to 500 $$\upmu $$ μ g L$$^{-1}$$ - 1 and 100 to 1000 $$\upmu $$ μ g L$$^{-1}$$ - 1 respectively. The LOD was 4.2 $$\upmu $$ μ g L$$^{-1}$$ - 1 (3S/N). Thanks to obtained calibration, a detected Zn(II) content of 1 ppm in a raw production water from North Sea oil platform was determined.

International audience; This work is a contribution to the global understanding of the coupling between kinetic and thermodynamic to explain the clathrate hydrates composition during their crystallization from a water liquid phase and a hydrocarbon gas phase. We faced new experimental facts that opened questioning after comparing the classical modeling of clathrate hydrates following the approach of van der Waals and Platteeuw with our experimental data following a new procedure allowing determining the hydrate composition during crystallization and at equilibrium. In our kinetic model (Herri et al, 2012), the enclathratation is described by means of a Langmuir absorption where the composition if fixed from kinetic consideration based on the balance between the absorption rate and desorption rate. These rates turn out to become dependent on the gas diffusion around the hydrate crystals, and so, the geometry of the system needs to be taken into account, especially the mass transfer at the Gas/liquid interface. The procedure results in the definition of nonequilibrium hydrate compositions with a new analytical expression for this composition. In this work, our contribution is to extract self-coherent experimental results from literature,, and to reevaluate properly the Kihara parameters. This step implies to compile and implement all the literature data in a data base of a modeling program (called GasHyDyn in our study). Then, we can optimize Kihara parameters from a procedure that can be trivial in some cases where literature data are rich enough to optimize directly the parameters. Then, from the comparison of experimental results (Bouillot et al., 2014, ICGH8) to the model (this work), we conclude that the experimental protocol can affect the composition of the hydrates, especially if the crystallization is operated near, or far from thermodynamic equilibrium.

International audience; Future thinking (FT) is the cognitive ability that enables humans to mentally imagine and pre-experience future events. Despite a sharp increase in basic research on future thinking in the last decade, we note the lack of transfer to Human Factors and Ergonomics (HF&E), although the field is increasingly concerned by future artefacts and although theory building on future-oriented HF&E has begun (e.g. prospective ergonomics). This article gives an overview of key findings regarding future thinking, namely i) underlying cognitive mechanisms, ii) functions and obstacles, iii) common descriptors of future thinking, iv) recommendations as to the possible improvement of future thinking during user research and, v) methods for the assessment of future thinking abilities. This synthesis can support HF&E practitioners in fine-tuning their future-oriented methods.

International audience; The elongated island of Palawan, bounded by two marginal basins, the South China Sea to the North and the SuluSea to the South is composed of remnants of an inverted basin (Proto-South China Sea) thrusted onto the marginof a continental terrane which rifted away from the Chinese-Vietnamese margin. Based on field observationscoupled with seismic and drill-holes data, our study focuses on the structural architecture of the island in order todecipher the geodynamic evolution of the southern margin of the South China Sea.Structurally, the Palawan Island consists of: (i) the Palawan wedge, which extends towards the South China Sea iscomposed of deformed slope to deep ocean deposits of Cretaceous (north Palawan) to Tertiary (central and southPalawan) ages. This accretionnary wedge is characterized by small wavelength folds of mainly NE-SW trend.Offshore, the unconformable Middle-Late Miocene Tabon limestones unit postdates the last stages of the Palawanwedge growth/setting; (ii) On top of this wedge lie thrust slices of ophiolite bodies comprising ribbon cherts ofAlbian age as indicated by radiolarians.; these bodies are likely to be relicts of the now-subducted Proto SouthChina Sea; (iii) The central and southern parts of the Palawan island are characterized by a large wavelengthantiform of NE-SW trend. This structure is sealed by the slightly tilted Early Pliocene marls unit; (iv) The islandalso presents necking zones bordered by N-S trending transform faults.This area witnessed the geodynamic evolution of the South East Asia which consists of a succession of opening/closure of oceanic basins and block accretions. The Palawan Island therefore results of the closing of theProto-South China Sea which once formed both the Palawan accretionary wedge and the overlying ophiolitetectonic slices. During a later compressive event, the rifted continental margin which composes the basement ofthe Island was inverted, inducing the uplift and the large scale folding of the Palawan Island. In a final stage, thestrain relaxing results in the formation of the necking zones, probably reactivating the inherited transform faultsof the Proto-South China Sea.

Conductive-probe atomic force microscopy (CP-AFM) measurements reveal the existence of a conductive channel at the interface between p-type hydrogenated amorphous silicon (a-Si:H) and n-type crystalline silicon (c-Si) as well as at the interface between n-type a-Si:H and p-type c-Si. This is in good agreement with planar conductance measurements that show a large interface conductance. It is demonstrated that these features are related to the existence of a strong inversion layer of holes at the c-Si surface of (p) a-Si:H/(n) c-Si structures, and to a strong inversion layer of electrons at the c-Si surface of (n) a-Si:H/(p) c-Si heterojunctions. These are intimately related to the band offsets, which allows us to determine these parameters with good precision.

Our understanding of the temporal variation of past stress in the crust is usually pictured in relation to tectonic contexts, where it helps decipher the evolution of deformation of rocks at different scales. The paucity of paleostress reconstructions in passive margins makes the knowledge of the origin of stress and of its evolution very incomplete, especially in poorly accessible offshore parts. Moreover, in salt-rich passive margins like the offshore Congo margin, one may question whether the state of stress in supra-salt formations is mainly controlled by salt tectonics, since the salt usually acts as a decoupling level that prevents the transmission and record of far-field crustal stresses. This study focuses on the analysis of an offshore wellbore core of the Albian, post-rift carbonates of the Sendji Fm that directly overlies the salt of the Aptian Loeme Fm in the Lower Congo Basin. Paleopiezometry based on stylolite roughness and mechanical twins in calcite was combined with fracture analysis, laser U-Pb dating of calcite cement, and burial modeling to unravel the tectonic and burial evolution of the Sendji Fm over time. The results of bedding-parallel stylolite roughness inversion constrain the range of depth over which the Sendji Fm strata deformed under a vertical principal stress s1 to 650-2800 m (median ~1100m). Projection of this depth range onto the Sendji burial model derived from TemisFlow™ basin modelling indicates that pressure solution was active from 105 to 12 Ma. Inversion of calcite mechanical twins measured within the early diagenetic cement (U-Pb age = 100 +/- 1Ma) yields two main states of stress: (1) an extensional stress regime with a horizontal σ3 trending ~E-W associated with sub-perpendicular N-S compression, and (2) a strike-slip stress regime with a horizontal σ1 trending ~E-W (changing from pure E-W compression to N-S extension through stress permutations). We interpret the former state of stress as local and related to the complex geometric interactions between moving halokinetic normal faults, while the latter presumably reflects the push effect of the Atlantic ridge, which prevailed from 12 Ma until present-day. Our results highlight that the stress history of the studied part of the offshore Lower Congo Basin passive margin has first been mainly dominated by burial and local normal faulting related to late Cretaceous to Miocene post-rift salt tectonics, then by a regional stress presumably originated from the far-field ridge push from ~12Ma onwards, which would indicate some mechanical re-coupling between the crust and the sedimentary cover during the Miocene.Keywords: stress, paleopiezometry, calcite twins, stylolites, passive margin, salt.

International audience; To construct accurate geological models of reservoirs and better predict their properties, it is critical to have a good understanding of the burial and stress history of the host sedimentary basin over time. Stress and strain are important factors influencing the preservation or reduction of reservoir porosity and permeability. One way to access the orientations and magnitudes of paleostresses is to use paleopiezometers. This study aims at reconstructing the stress and burial history of the syn-rift Barremian (130-125 Ma) Toca Fm in the Lower Congo basin (West African passive margin) using stress inversion of calcite mechanical twins and sedimentary and tectonic, bedding-parallel stylolite. This combined approach was applied to two oriented borehole cores drilled in a poorly deformed oil field, offshore Congo, and provided constraints on both paleostress orientations and magnitudes. The timing of the different paleostress regimes documented was derived from a burial-time model reconstructed by use of TemisFlowTM.The inversion of calcite twins was performed on a widespread early diagenetic cement (dated 127.4 ± 4.9 to 123.1 ± 7.7 Ma by U-Pb LA-ICPMS) and revealed two types of stress regimes. (1) An extensional stress regime with σ1 vertical and σ3 oriented either N50°±20° or N120°±20°, and mean differential stresses of 45 MPa for (σ1-σ3) and 20 MPa for (σ2-σ3). The NE-SW (N50°±20) extensional direction, which restores to N100° after moving back Africa to its position at Barremian times, marks the syn-rift extension that led to the opening of the South Atlantic. The 120° direction (~N-S after restoration) possibly reflects local perturbation and/or σ2-σ3 permutations during rifting in response to tectonic inheritance. (2) A compressional or strike-slip stress regime with horizontal σ1oriented ~E-W (and associated N-S extension) and mean differential stresses of 40 MPa for (σ1-σ3) and 15 MPa for (σ2-σ3). This suggests that the basin underwent a post-rift compressional history during the continuous burial of the Toca formation possibly related to the Atlantic ridge push effects. For the first time, we also reconstructed paleostress orientations from "tectonic" bedding-parallel stylolites, that developed during a tectonic extensional phase. The results point to a NE-SW extension consistent with the direction of the syn-rift extension revealed by calcite twinning. In order to constrain the sequence of stress evolution, we used the results of sedimentary stylolite roughness inversion paleopiezometry, which documents that the burial-related pressure solution in the Toca Fm occurred in the 400-1700m depth range (dissolution along 90% of stylolites halting between 700 and 1000m). Projection of this depth range onto the TemisFlowTM reconstructed burial-time curve of the Toca Fm indicates that vertical pressure solution was active between 122 and 95 Ma, and therefore that σ1 switched from vertical to horizontal around 95 Ma. Our study reveals that the Toca Fm has undergone a complex polyphase stress history during burial, with stress regimes evolving from extensional to compressional/strike-slip. It also illustrates the great usefulness of combining stress inversion of calcite twins and stylolite roughness with a burial-time model to constrain the stress history of a deeply buried reservoir.

A nano-gravimetric detector (NGD) for gas chromatography is based on a nanoelectromechanical array of adsorbent-coated resonating double clamped beams. NGD is a concentration-sensitive detector and its sensitivity is analyte-dependent based on the affinity of the analyte with the porous layer coated on the NEMS surface. This affinity is also strongly related to the NGD temperature (NGD working temperature can be dynamically set up from 40 to 220 °C), so the sensitivity can be tuned through temperature detector control. An adsorption-desorption model was set up to characterize the NGD response on a large set of n-alkanes from C10 to C22 at different NGD temperatures. For fast identification of petroleum mixture based on chromatogram fingerprint, a general strategy for NGD temperature program design was developed leading to a constant relative response factor between 0.96 and 1.03 for all the alkanes, and then chromatograms are very similar to those obtained with a flame ionization detector (FID). The analysis of a real petroleum fluid was also performed and compared to FID results: quantitative results obtained for all the analytes were satisfactory according to precision (

International audience; A boiling liquid expanding vapour explosion (BLEVE) is a physical explosion caused by a sudden rupture of a vessel containing superheated liquid. A BLEVE can occur with many types of fluids and is not an exclusive phenomenon for flammable liquefied gases such as propane or butane. Other superheated liquids suffering a fast depressurization at high temperature may entail a BLEVE, such as water in steam generation systems. Several pieces in literature suggest that superheated water may produce a BLEVE, but little experimental data can be found on that topic.The aim of this work was to perform water BLEVE tests with a 14 L pressure vessel designed on purpose to produce high superheated liquid water (290 °C; 75 bar) and to trigger a BLEVE through calibrated rupture disks. Pressure sensors were set in the vessel to measure the internal phase change pressure dynamics and other aerial overpressure sensors were put around the relief rupture disk to capture the blast wave. Temperature of water was also recorded, and a fast camera (Phantom V2512) was used to see the phenomenon.Data show clearly the pressure recovery due to rapid boiling in the vessel. Explosive boiling did not add additional internal pressure force on the containment. Two main blast waves were observed, they were strongly related with outlet orifice area but little dependant on filling ratio. The two phase jet reached a 20 m range.

International audience; Slope failure and landslides are widespread on the submarine slopes of carbonate platforms. They represent a key component of their stratigraphic evolution and a major geohazard. Several Quaternary slope failures and mass transport complexes were identified on the western slope and margin of the Great Bahama Bank (GBB) platform. This study evaluates several hypotheses for the preconditions associated to these events, in relation with the stratigraphic and environmental history of the platform. The forward stratigraphic simulator Dionisos Flow™ allows the slope stratigraphic evolution to be reconstructed on a 2D platform-to-basin section at high temporal resolution according to the eustatic and environmental history of the last 1.7 Myr. The hydromechanical simulator A2 is applied on this high-resolution stratigraphic grid for computing the mechanical stratigraphy of the section, that is the spatiotemporal pore pressure and stress state distribution. The simulated precondition of the platform margin during glacial lowstands results from the combination of two factors: transient overpressure generation by lateral fluid flow from the emerged platform and the steepening stratigraphic trend of the platform. No significant pore fluid overpressure is generated under high sedimentation rates or as a result of shift in hydrostatic gradient during sea-level falls. Precondition in the lower slope is not achieved in this 2D simulation, with the horizontal stress distribution counteracting the effect of overpressure build-up. It is found that cemented levels in the lower slope succession do not represent a significant preconditioning factor.

International audience; The Lez aquifer in southern France comprises low-porosity karstified limestones and provides drinking water for ~400,000 inhabitants. Population growth and climate change have increased the stress on the water resources. In order to provide long-term protection and to optimize the water supply, the hydrogeology of the Lez aquifer must be better characterized. This study focused particularly on the St-Clément major fault zone (12 km long with a 500-m normal throw) which was structurally characterized using accurate geological mapping of the area, outcrops analysis and geophysics tools. The research highlights and explains the close relationship between the fault and the karstic occurrences. Moreover, tracer tests and piezometric head variations in boreholes have shown (1) strong interconnection between the observed karstic formations and (2) the major role of St-Clément fault on mass and pressure transfers in the aquifer. At the reservoir scale, the other major faults of the Lez aquifer, such as Corconne-Matelles or Gourg Noir faults, have shown some common morphologic and dynamic characteristics, and suggest a similar hydrogeological functioning. This study then extends this model to a larger scale. It proposes that, in aquifers of low-porosity carbonates, fault zones control the development of the main karstic network which, in turn, controls the main groundwater flows. Thus, faults should be reconsidered in order to improve the vulnerability studies and the quality of karstic aquifer modelling. Therefore, this report can contribute to protecting the groundwater resource, improving yields and optimizing groundwater supply exploitation in this type of aquifer.

International audience; Widespread anoxic events affected the Tethys Ocean during the Mesozoic. The Ocean Anoxic Event 1a (Early Aptian), expressed as the Selli Level or Goguel Level (GL) in European basins. The GL was deposited in the French Vocontian Basin, a semi-enclosed basin connected to the Tethys Ocean. This study presents an integrated approach (Rock Eval, clay minerals, grain-size, inorganic geochemistry and molecular biomarkers), applied to four sections in the basin distributed along a proximal-distal transect. This study shows that the GL was perturbed by turbidites. In particular, the results demonstrate: (a) a homogeneous redox status of the basin that experienced oxic to suboxic conditions, according to trace element distributions and (b) low organic matter contents (total organic carbon ca 1 wt%) in the three sections where turbiditic deposits are observed. The distal, condensed section exhibits the highest organic matter contents (total organic carbon >3 wt%). In addition, the presence of gammacerane and isorenieratene derivatives in the distal sections suggests that the water-column was intermittently stratified, with hypoxia developing in the photic zone. This stratification did not result from strong surface productivity but more likely from: (a) limited renewal of deep water in the basin; (b) reputedly high surface-water palaeotemperatures during the Early Aptian; and (c) the influx of waters, possibly depleted in free oxygen and in some dissolved trace elements, into the basin. The turbiditic inputs, in addition to organic matter dilution in the sediments and a brief rupture of the water-column stratification in the proximal areas of the basin, ventilated the sea floor and more specifically re-oxidized the sediment-water interface as well as underlying sediments. Such episodes of benthic re-ox-ygenation could have altered the long-term palaeoredox record, even in the distal sections where reducing conditions prevailed during deposition. In the area deprived of turbiditic input, sedimentary condensation, coupled with low oxygen conditions, furthered organic matter preservation and concentration.

International audience; The Demerara and Guinea plateaus are conjugate Transform Marginal Plateaus (TMPs) formed at the junction of the Jurassic Central Atlantic Ocean and the Cretaceous Equatorial Atlantic Ocean. We compare their structure and evolution through a combined industrial/academic seismic dataset tied by well data. We show that these TMPs record a complete evolution history from the Jurassic Central Atlantic to the Equatorial Atlantic breakup and seafloor spreading phases. Both plateaus first formed as volcanic margins displaying successive SDR wedges migrating towards the newly forming Central Atlantic domain. In this context, Demerara and Guinea, conjugates of the Bahamas, seem to have formed in relation to plume activity at the southern end of the Central Atlantic domain. Our dataset suggests that the Demerara and Guinea plateaus initially represented two distinct extrusive centres separated by a crustal basement high. Later, during the Cretaceous Equatorial opening phase, both plateaus separated in a transform mode following this discontinuity. Deformation is notably asymmetric during this phase: Aptian to Albian folding, strike-slip, transtensive deformation and complex vertical movements on the Demerara side and only minor deformation on the Guinean side, except on its divergent Sierra Leone termination. The deformation is sealed on both plateaus by a regional upper Albian erosion unconformity. Extensional reactivation occurs on the Guinea side (probably through a general collapse?). To conclude, this study provides new insights into the nature and origin of TMPs and the key tectono-sedimentary archives they may contain to understand the polyphase breakup conditions of Gondwana.

National audience; The continental rifted margins of Mozambique provide an excellent example ofcontinental passive margins with a significant structural variability associated tomagmatism and inheritance. Despite accumulated knowledge in this area, the tectonicstructure and nature of the crust from Mozambique margins, especially the Limpopotransform margin are still poorly known. Here, we use high-resolution seismicreflection dataset and wells from industry to propose a structural interpretation of thisarea.Our results indicate that the Limpopo transform fault zone limits a continental crustwestward, with deep Karoo grabens, from an oceanic crust domain eastward. TheLimpopo transform margin also shows a widespread magmatism, attested by thepresence of lava flows and highly magmatic oceanic crust, implying different thermalperturbations through time and space.We suggest that the expression of thermal perturbations started with the Karoo LargeIgneous province emplacement at about 180 Ma. This intense magmatism event isfavored by pre-existing and neo-formed faults, which may contribute significantly to thedistribution of magma generated. We propose an evolution model from the onset of therifted margin to the seafloor spreading along the Limpopo magma-rich transformmargin with (i) an E-W extension trend responsible for the formation of a large faultcontrolledbasin during the Permo-Trias (T1); (ii) the extension becoming NNW-SSE,oblique to the margin direction as attested by the presence of flower structures, allowsfor reactivation of previous structures inducing the deposition of a volcanosedimentarywedge, and the formation of several magmatic infilling during the Jurassic(T2); (iii) the onset of oceanic spreading after ca. M25 (i.e. 156 Ma) in the Limpopo areawhich triggered the uplift and erosion of the proximal parts of the margin as well as theformation of several other magmatic infilling (T3).

Aim Past pollen records reveal the changes in latitudinal distribution of plants in relation to climate, particularly their expansion in response to global warming. The maximum northward expansion of the mangrove genus Avicennia since the Early Eocene is known, but this information is missing for other mangrove taxa. Here, we evaluate the diversity of past mangroves with respect to latitude during three Cenozoic thermal maxima (PETM: 56 Ma; EECO: 54–49 Ma; MMCO: 17–14 Ma). Location North Atlantic, Mediterranean. Taxa Avicennia, other mangrove taxa (Rhizophoraceae, Nypa, Xylocarpus, Pelliciera, etc.). Method We collected well-dated marine sediments along a Northern Hemisphere latitudinal transect and we analysed their pollen content in order to compare the past distribution of mangrove taxa with the present. The analysis of 89 samples (PETM: 13; EECO: 31; MMCO: 45) was performed and interpreted using a robust botanical background for identification of pollen grains and their representativeness in marine sediments. Results During the Early Eocene, two palaeolatitudinal thresholds at 65–70°N and 35°N, respectively, delimited the Avicennia-only mangrove from a diversified but scrawny mangrove and finally from a diversified and well-developed mangrove. The Avicennia threshold was selective at 40°N during the Mid-Miocene. The Avicennia range limit was up to 10–15° poleward of the limit for other mangrove taxa during the Early Eocene and the Mid-Miocene compared with 9° at present. Main conclusions A buffer zone characterised by a diversified but scrawny mangrove co-occurring with a few megathermal plants occurred in the Early Eocene between 35°N and 65–70°N. This finding questions the relative influence of a more ‘equable’ climate and/or the ability of some taxa to expand towards areas with cooler conditions in the past. Mangrove provincialism, which was established progressively after the Early Eocene, was probably forced by plate tectonics. The taxonomic impoverishment of the Atlantic East Pacific province was probably caused by successive periods of global cooling. These results support the Tethyan origin of the mangroves.

National audience; Environ 70% du relief émergé terrestre est caractérisé par des surfaces érosivespossédant un faible gradient topographique, aussi appelées surfaces d’aplanissement.Certains géomorphologues défendent l’idée que ces surfaces sont des reliques d’ancienspaléoreliefs, partiellement préservés des phénomènes d’érosion durant des dizaines demillions d’années. Une telle préservation en ferait les témoins privilégiés de l’évolutiondes surfaces continentales, depuis la formation de ces surfaces jusqu’à nos jours.Certaines des plus hautes surfaces d’aplanissement d’Afrique, localisées à plus de 2000m d’altitude, sont considérées dans la littérature comme étant des reliques d’unesurface Mésozoïque, la Gondwana surface (King, 1962). En particulier, le plateau deNyika (ca 2200 a.s.l.), localisé au nord du Malawi, est l’une des plus importantesreliques potentielles de cette paléosurface. Toutefois, la possibilité de préserver desreliefs aussi anciens est un sujet débattu dans la littérature, particulièrement sous unclimat tropical.L’exploration de ce plateau a permis d’identifier un niveau de cuirasse détritique,aujourd’hui sur un haut-topographique. Cette cuirasse, composé de clastes d’unecuirasse primaire riche en hématite cimentés par une matrice goethitique, a été datégrâce à la méthodologie de datation (U-Th)/He des oxydes et hydroxydes de fer.L’analyse minéralogique et géochimique de grains en provenance des clasteshématiques révèle la complexité de ces zones, qui sont pour la plupart composées d’unmélange de générations d’oxydes de fer. La datation de cette cuirasse a toutefois permisde faire ressortir que sa matrice possède un âge Quaternaire. A contrario, certainsclastes préservés, peu impactés par les phénomènes de dissolution/recristallisation àl’origine des mélanges générationnels, possèdent des âges remontant au Dévonien.La topographie initiale du plateau n’a pas été préservée, des bancs de cuirassesdétritiques se retrouvant aujourd’hui sur des hauts topographiques. Toutefois, cesrésultats montrent que des cuirasses détritiques se sont développés sur cette surface, ousur une surface supérieure adjacente, au cours du Dévonien avant d’être érodées pourpermettre de former les cuirasses aujourd’hui en surface. Par ailleurs, cette étude tendà supporter l’idée que le cuirassement des plateaux en contexte tropical joue un rôle clédans leur préservation.

International audience; Le bassin d’Aquitaine est marqué par un changement majeur au cours du Cénozoïque, il devient le retro bassin d’avant-pays du système pyrénéen. De nombreuses études se sont focalisées sur l’évolution du remplissage sédimentaire durant la phase paroxysmale de l’orogénèse pyrénéenne. Cependant peu d’études se sont intéressées au remplissage molassique durant la phase finie-orogénique à post-orogénique.Afin de mieux contraindre le calendrier tectono-sédimentaire de la transition entre ces deux stades d’évolution, notre étude se base sur un nouveau modèle d’âge obtenu à partir de nouvelles données biostratigraphiques et raffiné grâce à l’orbitostratigraphie. Ce modèle d’âge met pour la première fois en corrélation les dépôts molassiques proximaux (Lannemezan) et leur équivalents marins (Golfe de Gascogne). Les nombreuses données disponibles (40 000 km de sismique réflexion, 1600 puits) ont été interprétées grâce aux méthodes de - « stacking pattern » - et de stratigraphie sismique - « shoreline trajectory ». La synthèse de ces données est présentée sous forme de coupes et de cartes (isohypses, isopaques, paléogéographiques) qui renseignent précisément sur l’évolution de ces deux bassins. Les principaux résultats sont :(1) La période finie orogénique est marquée par la migration à la fois vers l’Ouest mais également vers le Nord des dépotcentres(2) La transition de syn- à post-orogénique se fait entre 27.1 Ma et 25.2 Ma, elle est matérialisée par la présence de trois discontinuités (érosion/by-pass) majeures recouvertes par une sédimentation tabulaire qui scellent les structures compressives(3) Le début de la période post-orogénique (entre 25.2 et 16.4 Ma) est remarquable par l’absence de sédiments préservés dans la partie proximale du bassin qui marque la mise en place du rebond isostatique(4) La suite de la période post-orogénique est marquée par un soulèvement majeur entre 16.4 Ma et 10.6 Ma du bassin d’Aquitaine sans doute contrôlé par la dynamique mantellique ouest européenneCe travail a été financé par le BRGM-TOTAL dans le cadre du projet Source-to-Sink.

International audience; This study investigated the impact of seasonal variations on the productivity of Nannochloropsis oculata culture, cultivated in an outdoor pilot scale open pond raceway over 16 months. The 2.5 m3 pilot (i.e. water depth of 20 cm) was operated under phototrophic conditions in a simulated marine environment at 50 g.L−1 of salinity. Results revealed that culture growth rates, doubling times and productivity were highly impacted by weather conditions with a good reproducibility of seasonal features. During summer, growth rate (i.e. 0.15 d−1) was higher than in winter (i.e. +300%) and in spring-autumn (i.e. +40%). Average areal productivities were higher during summertime (i.e. 13.2 t.ha−1.y−1 or 3.61 g.m−2.d−1) compared to those of winter (i.e. +264%) and autumn-spring conditions (i.e. +90%). Monthly correlation analysis revealed also a significant correlation between productivity and weather conditions (i.e. higher than 0.85), especially during culture periods not affected by microbial contamination, while daily correlation analysis showed that microalgae have a relative long-time spread response (i.e. about 10 days) to change in weather conditions. Therefore, the monthly approach appeared more suitable for considering weather effects over microalgae culture

Industrial digital transformation is bringing a need for new tools and concepts. However, designing such complex tools and concept requires methods to be correctly implemented. These methods are studied as part of system engineering to satisfy various identified goals, and more specifically human-system integration, which is the topic of this paper. This article introduces the method used to define key elements of human perception of reality called reality anchors to design scenarios to be tested in a digital twin prototype. This method goes from regulation study to user cognitive function analysis on the specific case of digital twin designing in oil-and-gas industry. This method highlighted the differences between theoretical process and the followed process as well as tools and competencies used to identify reality anchors. This knowledge will then be used to implement a new process to be implemented with a digital twin and scenarios to test the prototype using realistic simulation.

International audience; Treatment of hydrogen sulfide (H2S) is important in many industrial processes including oil refineries, natural and biogas processing, and coal gasification. The most mature technology for the selective capture of H2S is based on its absorption by chemical or physical solvents. However, only several compounds are currently used as physical (co)solvents in industry, and the search for new ones is an important task. The experimental screening of physical (co)solvents requires much time and many resources, while solubility modeling might enable one to reduce the number of solvents for the experimental evaluation. In this study, a workflow for the in silico discovery of new physical solvents for H2S absorption was suggested and experimentally validated. A data set composed of 99 H2S physical solvents was collected and predictive quantitative structure–property relationships for H2S solubility were built using a random forest algorithm and two types of molecular descriptors: ISIDA fragments and quantum-chemical descriptors. Virtual screening of industrially produced chemicals and their structural analogues enabled identification of the ones with predicted high solubility values. They can be suggested as starting points for further exploration of the H2S physical solvents chemical space. The predicted solubility value for one of the compounds found in virtual screening, 1,3-dimethyl-2-imidazolidinone, was confirmed experimentally.

After more than a century of research, the chronology of the deformation of the external part of the western Alpine belt (France) is still controversial for the Miocene epoch. In particular, the poor dating of the foreland basin sedimentary succession hampers a comprehensive understanding of the deformation kinematics. Here we focus on the Miocene molasse deposits of the northern subalpine massifs, southern Jura, Royans, Bas-Dauphiné, Crest, and La Bresse sedimentary basins through a multidisciplinary approach to build a basin-wide tectono-stratigraphic framework. Based on sequence stratigraphy constrained by biostratigraphical, chemostratigraphical (Sr isotopes), and magnetostratigraphical data between the late Aquitanian (∼ 21 Ma) and the Tortonian (∼ 8.2 Ma), the Miocene molasse chronostratigraphy is revised with a precision of ∼ 0.5 Ma. The Miocene molasse sediments encompass four different paleogeographical domains: (i) the oriental domain outlined by depositional sequences S1a to S3 (∼ 21 to ∼ 15 Ma), (ii) the median domain characterized by sequences S2 to S5 (∼ 17.8 to ∼ 12 Ma), (iii) the occidental domain in which sequences S2a to S8 (∼ 17.8 to ∼ 8.2 Ma) were deposited, and (iv) the Bressan domain where sedimentation is restricted to sequences S6 to S8 (∼ 12 to ∼ 8.2 Ma). A structural and tectono-sedimentary study is conducted based on new field observations and the reappraisal of regional seismic profiles, thereby allowing the identification of five major faults zones (FZs). The oriental, median, and occidental paleogeographical domains are clearly separated by FZ1, FZ2, and FZ3, suggesting strong interactions between tectonics and sedimentation during the Miocene. The evolution in time and space of the paleogeographical domains within a well-constrained structural framework reveals syntectonic deposits and a westward migration of the depocenters, allowing for proposing the succession of three deformation phases at the western Alpine front. (i) The first is a compressive phase (P1) corresponding to thrusting above the Chartreuse oriental thrust (FZ1), which was likely initiated during the Oligocene and rooted east of Belledonne. This tectonic phase generated reliefs that limited the Miocene transgression to the east. (ii) The second is a ∼ WNW–ESE-directed compressive phase (P2) lasting between 18.05 ± 0.25 Ma and ∼ 12 Ma, with thrusts rooted in the Belledonne basal thrust. Thrusts were activated from east to west: the Salève (SAL) and Gros Foug (GF) thrusts and then successively FZ2, FZ3, FZ4, and FZ5. Along two WNW–ESE balanced cross sections the amount of horizontal shortening is of ∼ 6.3 to 6.7 km, corresponding to average shortening rates of ∼ 1.2 km Myr−1 and migration of the deformation toward the west at a rate of ∼ 2.9 km Myr−1. During ∼ 6 Myr, the Miocene Sea was forced to regress rapidly westwards in response to westward migration of the active thrusts and exhumation of piggyback basins atop the fault zones. Phase P2 thus deeply shaped the Miocene paleogeographical evolution of the area and appears as a prominent compressive phase at the scale of the western Alps from the Swiss molasse basin to the Rhodano–Provencal one. (iii) The third is a ∼ 300 m phase of uplift in the Bas-Dauphiné (P3) of probable Tortonian age (∼ 10 Ma), which would have induced southward sea retreat and been coeval with the folding of the Jura in the north and possibly with back-thrusting east of the Chartreuse massif.

International audience; Black shales, though laminated, are not systematically synonymous with quiet conditions of deposition. A number of papers report about black shales yielding sedimentary structures echoing relatively high hydrodynamic conditions. Here we examine two sedimentary sequences pertaining to the Late Jurassic Argiles de Châtillon Formation of the Boulonnais area (Northernmost France), each of them including a meter-thick black-shale horizon. The two laminated black shales contain sulfurized (i.e., organic S-rich) organic matter, reaching a maximum of 9%. However, some differences set the two black shales apart. The lower one was deposited under calm, suboxic to anoxic, bottom-water conditions (the « classic » way); the upper black shale was deposited under oxic, agitated bottom-water conditions, not compatible with stable sulfidic conditions required for organic-matter sulfurization. The upper black shale experienced hydrodynamically-induced concentration of sulfurized, recalcitrant organic matter of marine origin. The sulfurized organic matter could be preserved and quantitatively accumulated owing to its non-putrescible nature, leading to the formation of a potential hydrocarbon source rock. The association of pyrite inclusions with sulfurized organic matter probably modified the hydrodynamic behavior of organic particles. The storm-induced remobilization and concentration of sulfurized organic matter implies that the “sulfurization factory” operated in proximal, shallow environments such as estuaries, mud flats or mangrove environments. Such a model is in agreement with findings from modern coastal/shelf environments (notably mangroves) and fully transposable to many other sedimentary situations of any geological time period.

In industry, many heterogeneous solid/gas reactions are exothermic. Consequently, the radial heat transfer properties can be an important key for the process optimization. In this context, thermal tests were conducted in an innovative laboratory pilot. Radial temperature profiles are measured between a central hot-wire and the cooling jacket of the tube. Two models were presented in order to estimate the heat transfer coefficients from the experimental data. The results are discussed and compared with the main literature correlations. The influence of the particle shapes on heat transfers and the pressure drop is investigated.

International audience; The relationships between the margin sedimentary regime and the platform progradation are studied using forward stratigraphic numerical simulations on the Leeward (Western) prograding margin of the Great Bahama Bank (GBB) during the Quaternary (1.7–0 Ma). The corresponding sedimentary regime in the slope and the platform is well known from the ODP leg 166 and Bahamas Drilling Project wells located along the “Western line” seismic transect. However the sedimentary regime on the margin is not well established: the coral reefal margin observed before between 1.7 and 0.8 Ma in the well Clino is not active anymore at present-day, and the Holocene sedimentary regime is geometrically unable to account alone for the progradation. This study is based on three 2D high-resolution forward stratigraphic numerical modeling experiments with the software DionisosFlow that include the platform, margin and slope domains on the “Western Line Section” in the same sedimentary models. The results are compared to the six sedimentary cores and to the present day bathymetry in order to identify the more realistic scenario. The three experiments test different models of carbonate sediment production and transport. Experiment 1 shows that the highstand shedding of the fine-grained uncemented platform production is unable to reproduce the progradation and the present-day profile. Experiments 2 and 3 incorporate cemented facies in the margin, with the best results obtained with the cemented marginal wedges produced in Experiment 2 during platform emersion. From these results a high-resolution interpretation of the margin seismic section is proposed. This study shows that the platform progradation can be decoupled from the highstand shedding of the fine-grained platform production. It is dependent on the accumulation in front of the steep margin of coarse or cemented material. Before 0.8 Ma this corresponds to the coral reef identified in Clino. The transition after 0.45 Ma to 100-kyr large eustatic cycles with total platform flooding created two distinct marginal regimes: (1) during platform flooding aggrading accumulation of non-skeletal sands, and (2) during platform emersion prograding cemented marginal wedges produced in-situ.

International audience; Piggyback basins often display asymmetric sedimentary successions influenced by both regional and local syn-depositional tectonic structures. There are few examples where a complete exhumed piggyback basin fill can be analyzed, from proximal, close to source areas, to the distal deep-water sinks. The study of these basins is a key to extract the stratigraphic signal of intrabasinal tectonics, which often competes and can even overprint other controlling factors such as eustasy, climate, or autogenic processes. The purpose of this paper is to propose a more detailed model of the evolution of piggyback basin fills, which recognizes the influence of intrabasinal tectonic activity, specific to the piggyback context and the resulting stratigraphic architecture. We investigate the Tremp-Graus-Ainsa piggyback basin, located in the southern Pyrenees, during early Eocene, which was influenced by the development of the Montsec frontal thrust. Twenty four stratigraphic sections, totaling 14 km of logged thickness, are analyzed, covering 60 km of the basin. The stratigraphic surfaces have been correlated in order to define large-scale stratigraphic units and a new sequence stratigraphic framework. The influence of local tectonics in the basin record is identified by abrupt lateral sediment thickness variations, abrupt changes of depositional environments, local erosion surfaces, and changes in dominant sedimentary process regimes and paleocurrent directions through space and time. As a result, we propose a new tectono-stratigraphic model for the development of the Tremp-Graus-Ainsa Basin. Specifically, we identify (1) an underfilled stage with initial high flexural subsidence and a frontal subaqueous blind anticline thrust propagation that controls a dominantly carbonate environment, followed by a progressive increase in siliciclastic sediment supply, and (2) an overfilled stage with an increase in frontal thrust propagation causing new emergent sediment sources. This second stage evolves from an active emerged blind anticline thrust to a migrating thrust that moved along lateral ramps, and which caused the decoupling of the Tremp-Graus uplifted wedge-top sub-basin from the Ainsa subsiding foredeep domain. Finally, we provide a new model intrinsic to the piggyback basin development with four main stages, controlled by changes in intrabasinal tectonic activity, flexural subsidence and orogeny axial zone evolution, which ultimately modulate sediment supply and creation and distribution of accommodation space.

International audience; Cryogenic cameras are an innovative alternative in the design of miniaturized infrared cameras using cryogenic detectors. In this presentation, we will apply this technology to design a snapshot multispectral camera for gas leak detection. A UAV compatible demonstrator in a commercial Detector Dewar Cooler Assembly (DDCA), called SIMAGAZ, has been made and tested in the TOTAL Anomaly Detection Initiatives (TADI) platform and the Esperse site of ONERA. The TADI infrastructure manages monitored gas leaks at flowrates from 0.1 g/s to 300 g/s and hosts remote sensors to test them in three scenarios: crisis-management, safety monitoring, and environmental monitoring. In Esperse site, first UAV flights with SIMAGAZ were performed. We demonstrate the ability to detect and quantify in real time the origin of methane gas leak, the flowrate and the volume of the plume with SIMAGAZ on ground or from a UAV. The core camera weights around 1kg, for around 1L footprint and a power consumption of 10W at the cooling steady state. Results from TADI and Esperse campaigns will be presented.

The North Natal Valley (NNV) and the Mozambique Coastal Plain (MCP) are key areas for the understanding of the SW Indian Ocean history since the Gondwana break‐up. Nevertheless, the deep structures and the nature of the NNV and MCP remain discussed in the absence of deep geophysical data. In 2016, the NNV, MCP and Limpopo margin (LM) have been investigated along 7 wide‐angle and MCS profiles. The combined wide‐angle and reflection seismic interpretation along the N‐S MZ7 profile reveals an upper sedimentary sequence characterized by low velocities generally not exceeding 3 km/s, with thicknesses varying from 0.150 km in the central part to ∼2.8 km in the south. The underlying sequence is formed of a 2.5‐3.0 km thick volcano‐sedimentary sequence which presents important lateral and with depth changes and presence of high velocity lenses, indicating inter‐bedded volcanic sills and recurrent magmatic episodes. The south of the NNV including the Naude Ridge (NR) presents a disturbed sedimentary cover with structural highs and southward‐dipping reflectors and sub‐basins. The crust, reaching 35‐40 km onshore below the MCP, gently thins below the continental shelf to a regular thickness of ∼29 km below the NNV. Crustal velocities reveal low velocity gradients, with atypical high velocities. South the ND, the crust thins to 15 km. We interpret the velocity architecture combined with the evidences of volcanism at shallower depths as indicating an intensively intruded continental crust. Contrary to what is proposed in most geodynamic models, the Mozambique Coastal plain and the Natal Valley are both of continental nature, with an abrupt necking zone located south of NR. The Antarctica plate was therefore situated at the eastern limit of these two domains before the Gondwana breakup. Plain Language Summary About 200Ma ago, the mega‐continent Pangaea broke up. The dispersion of the pieces of this mega‐continent, linked to the closure and disappearance of the Thetys paleo‐ocean, gave the birth of the Atlantic and Indian Oceans. In detail, the initial position of each piece of this jigsaw is of great importance as it has an impact on the palaeotopography and palaeogeography, and our understanding of the genesis of the continental passive margins, the role of tectonic inheritance, the pre‐rift and post‐rift evolution of the topography dynamic (vertical movement) and of the geodynamic of the plates (horizontal movement). Nevertheless, in the Western Indian Ocean, the initial pre‐beak‐up position of Antarctica plate respect to Africa plate is still under debate, mainly due to the lack of deep geophysical data. In 2016, an academic‐industrial collaboration succeeded in acquiring deep information along 7 seismic profiles crossing the North Natal Valley off the coast of Mozambique. The results falsify the presence of an oceanic crust in that area and thus most of the plate reconstruction models. They also argue in favour a new paradigm for the genesis of continental passive margin.

International audience; We document the role of sedimentary burial and salt tectonics in controlling the deformation style of continental crust during hyperextension. The Iberian-European boundary records a complex history of Cretaceous continental extension, which has led to the development of so-called smooth-slope type basins. Based on the review of the available geological constraints (crustal-balanced cross sections, sedimentary profile evolution, RSCM thermometer, low-temperature thermochronology) and geophysical data (Bouguer anomaly, Moho depth, seismic reflection profiles, and Vp/Vs velocity models) on the Tartas, Arzacq, Cameros, Parentis, Columbrets, Mauléon, Basque-Cantabrian and Internal Metamorphic Zone basins, we shed light on the main characteristics of this type of basin. This synthesis indicates that crustal thinning was influenced by two decoupling horizons: the middle crust and Triassic pre-rift salt, initially located between the basement and pre-rift sedimentary cover. These two horizons remained active throughout basin formation and were responsible for depth-dependent thinning of the crust and syn-rift salt tectonics. We therefore identify several successive deformation phases involving (1) pure shear dominated thinning, (2) simple shear dominated thinning and (3) continental breakup. In the first phase, distributed deformation resulted in the development of a symmetric basin. Field observations indicate that the middle and lower crust were under dominantly ductile conditions at this stage. In the second phase, deformation was localized along a crustal detachment rooted between the crust and the mantle and connecting upwards with Triassic pre-rift salt. During continental breakup, basin shoulders recorded the occurrence of brittle deformation while the hyperextended domain remained under predominantly ductile thinning. The formation of smooth-slope type extensional basins was intrinsically linked to the combined deposition of thick syn-rift and breakup sequences, and regional salt tectonics. They induced significant burial and allowed the continental crust and the pre-rift sequence to deform under high temperature conditions from the rifting to continental breakup stages.

International audience; In real-life machine learning applications, a common problem is that raw data (e.g. remote sensing data) is sometimes inaccessible due to confidentiality and privacy constrains of corporations, making classification methods arduous to work in the supervised context. Moreover, even though raw data is accessible, limited labeled samples can also seriously affect supervised methods. Recently, supervised and unsupervised classification (clustering) results related to specific applications are published by more and more organizations. Therefore, combination of supervised classification and clustering results has gained increasing attention to improve the accuracy of supervised predictions. Incorporating clustering results with supervised classifications at the output level can help to lessen the recline on information at the raw data level, so that is pertinent to improve the accuracy for the applications when raw data is inaccessible or training samples are limited. We focus on the combination of multiple supervised classification and clustering results at the output level based on belief functions for three purposes: (1) to improve the accuracy of classification when raw data is inaccessible or training samples are highly limited; (2) to reduce uncertain and imprecise information in the supervised results; and (3) to study how supervised classification and clustering results affect the combination at the output level. Our contributions consist of a transformation method to transfer heterogeneous information into the same frame, and an iterative fusion strategy to retain most of the trustful information in multiple supervised classification and clustering results.

International audience; This study focuses on the development of a hybrid biological reactor for the treatment of synthetic oilfield produced water. To face increasingly strict regulations concerning produced water discharge, a fixed bed hybrid biological reactor (FBHBR) containing a combination of free activated sludge and a fixed biofilm support was compared to a conventional activated sludge reactor (CAS). After gradual microbial acclimation, a 133-day experiment showed that both bioreactors were able to efficiently remove phenol, toluene, xylenes, and polycyclic aromatic hydrocarbons (PAHs) from a synthetic wastewater with a chemical oxygen demand (COD) removal rate above 95%, at hydraulic retention times (HRT) of 24 h and 18 h, and that only the FBHBR was able to maintain high removal efficiency at an HRT of 12 h. Ecotoxicity tests showed that outlet waters from both bioreactors were non-toxic. Assessment of the bacterial population revealed notable differences between the CAS reactor and FBHBR. In particular, wider diversity was observed in the FBHBR. The marked similarity between the bacterial composition of the free sludge and that of the biofilm in the FBHBR suggests that biofilm detachment played an important part role in bacterial development in the free sludge.

International audience; We report on the contact line dynamics of a triple-phase system silica/oil/water. When oil advances onto silica within a water film squeezed between oil and silica, a rim forms in water and recedes at constant velocity. We evidence a sharp (three orders of magnitude) decrease of the contact line velocity upon the addition of cationic surfactants above a threshold concentration, which is slightly smaller than the critical micellar concentration. We show that, with or without surfactant, and within the range of small capillary numbers investigated, the contact line dynamics can be described by a friction term that does not reduce to pure hydrodynamical effects. In addition, we derive a model that successfully accounts for the selected contact line velocity of the rim. We further demonstrate the strong increase of the friction coefficient with surfactant bulk concentration results from the strongly nonlinear adsorption isotherm of surfactants on silica. From the variations of the friction coefficient and spreading parameter with surface concentration, we suggest a picture in which the part of the adsorbed surfactants that are strongly bound to the silica interface is trapped under the oil droplet and is responsible for the large increase in line friction.

National audience; La réinterprétation des données de sub-surface dans le bassin d’Aquitaine et les travaux menéssur les Corbières où affleurent le piémont pyrénéen permettent de reconstituer la déformationde ce retroforeland et l’évolution du système source to sink au cours de la période synorogénique,Eocène.Après une phase de quiescence paléocène, l’activité tectonique est marquée dans le bassin par(1) une reprise de subsidence à la fin du Thanétien, (2) la mise en place d’un bassin flexural(Yprésien- Lutétien), contemporain de l’augmentation de la taille de la chaine, et (3) lasegmentation de ce bassin par la réactivation d’accidents hérités à partir du Bartonien, quicorrespond à la collision sensu stricto. A ces trois phases, correspondent des systèmes source tosink différents, et permettent de préciser la compréhension des stades classiques (underfilled,filled, overfilled).1- Le Paléocène (quiescence) enregistre une sédimentation carbonatée qui évolue depuisdes systèmes récifaux vers des systèmes de rampes carbonatées. Durant le Thanétiensupérieur (début de la période syn-orogénique), se mettent en place des systèmesturbiditiques mixte terrigène-carbonaté, alimentés par le Massif Central etvraisemblablement par les premiers reliefs pyrénéens orientaux.2- L’Yprésien (orogenèse précoce) correspond à la croissance progressive des reliefspyrénéens, et une augmentation des apports pyrénéens. Un remplissage rapide duretroforeland par des dépôts deltaïques a lieu. Les influences respectives desévènements climatiques du début de l’Yprésien et de la déformation de l’avant-pays surles volumes érodés et les architectures sédimentaires seront discuses. Le comblementprogressif du bassin génère une large zone de transfert à partir du Lutétien.3- Le Bartonien (collision) correspond à une exhumation importante de la chaine. Dans lebassin d’Aquitaine, l’inversion des structures héritées génère la mise en place demultiples dépôt-centres plus ou moins déconnectés. Il en résulte une modificationmajeure du système source to sink, dans lequel l’augmentation des apportssédimentaires se traduit par un très faible export vers le bassin profond et uneaggradation importante des piémonts.

Fault damage zones strongly influence fluid flow and seismogenic behavior of faults and are thought to scale linearly with fault displacement until reaching a threshold thickness. Using analog modeling with different frictional layer thicknesses, we investigate damage zone dynamic evolution during normal fault growth. We show that experimental damage zone growth with displacement is not linear but progressively tends toward a threshold thickness, being larger in the thicker models. This threshold thickness increases significantly at fault segment relay zones. As the thickness threshold is approached, the failure mode progressively transitions from dilational shear to isochoric shear. This process affects the whole layer thickness and develops as a consequence of fault segment linkage as inferred in nature when the fault matures. These findings suggest that fault damage zone widths are limited both by different scales of mechanical unit thickness and the evolution of failure modes, ultimately controlled in nature by lithology and deformation conditions.

We present a local-scale atmospheric inversion framework to estimate the location and rate of methane (CH4) and carbon dioxide (CO2) releases from point sources. It relies on mobile near-ground atmospheric CH4 and CO2 mole fraction measurements across the corresponding atmospheric plumes downwind of these sources, on high-frequency meteorological measurements, and on a Gaussian plume dispersion model. The framework exploits the scatter of the positions of the individual plume cross sections, the integrals of the gas mole fractions above the background within these plume cross sections, and the variations of these integrals from one cross section to the other to infer the position and rate of the releases. It has been developed and applied to provide estimates of brief controlled CH4 and CO2 point source releases during a 1-week campaign in October 2018 at the TOTAL experimental platform TADI in Lacq, France. These releases typically lasted 4 to 8 min and covered a wide range of rates (0.3 to 200 g CH4/s and 0.2 to 150 g CO2/s) to test the capability of atmospheric monitoring systems to react fast to emergency situations in industrial facilities. It also allowed testing of their capability to provide precise emission estimates for the application of climate change mitigation strategies. However, the low and highly varying wind conditions during the releases added difficulties to the challenge of characterizing the atmospheric transport over the very short duration of the releases. We present our series of CH4 and CO2 mole fraction measurements using instruments on board a car that drove along roads ∼50 to 150 m downwind of the 40 m × 60 m area for controlled releases along with the estimates of the release locations and rates. The comparisons of these results to the actual position and rate of the controlled releases indicate ∼10 %–40 % average errors (depending on the inversion configuration or on the series of tests) in the estimates of the release rates and ∼30–40 m errors in the estimates of the release locations. These results are shown to be promising, especially since better results could be expected for longer releases and under meteorological conditions more favorable to local-scale dispersion modeling. However, the analysis also highlights the need for methodological improvements to increase the skill for estimating the source locations.

International audience

International audience; CO2 Capture and Storage (CCS) is gradually gaining global recognition as a vital technology to complement the climate change mitigation portfolio. Since CCS entered the public arena with the publication of the IPCC Special Report in 2005, most of the international prospective scenarios compatible with keeping the temperature rise below 2°C rely on CCS (e.g. IPCC, IEA). International initiatives gathering many volunteer countries are playing a key role for enabling the development and deployment of CCS, such as IEAGHG since 1991, CSLF since 2003, ISO/TC 265 since 2011, Mission Innovation Challenge 3 since 2015, SET Plan Action 9 since 2016. Quite recently the use (U) of CO2 has entered the value chain to encourage the economic use of part of the captured CO2 as a raw material for the manufacture of new products before permanently storing the rest in the deep subsurface, this is why the technology is now often referred to as CCUS, or CCS and CCU. France has played a key role in the development of global climate policies (e.g. the Paris agreement in 2015), and is involved in the various international initiatives devoted to CCUS mentioned above. It is therefore interesting to take stock of how France is preparing to develop this technology and deploy it on its territory. Are we heading towards the deployment of the CCUS technology in France?

International audience

International audience; We report on the thinning mechanisms of supported films of surfactant (nTAB) solutions above the critical micellar concentration. The films are formed by pressing an oil drop immersed in an aqueous surfactant solution on a silica surface. Depending on the length of the carbon chain of the surfactant and its concentration, two modes of destabilisation of the stratified films are observed. The first one proceeds by heterogeneous nucleation, characterised by the lateral expansion of the domain of lower thickness, as evidenced long ago in suspended micellar films. In addition, the simultaneous stepwise thinning of several domains, called spinodal stratification, is observed here for the first time in supported films. We measure the time evolution of the thickness of the films and we discuss the selection mechanism of each destabilisation mode.

International audience