GENII, une plate-forme pour le développement d'applications d'interprétations d'image

- Le système d'interprétation présenté ici trouvera son utilité si l'on désire manipuler des informations structurelles et spatiales issues d'images 2D. En effet, ce type d'information se manipule plus facilement dans le domaine symbolique, sous la forme de relations entre noeuds, arcs et faces, que dans le domaine matriciel où il est difficile d'ajouter des information structurelles aux pixels

Experimental study of infrared-convective drying of hydrous ferrous sulphate

International audienc

Water tracers in oilfield applications: Guidelines

International audienceA key parameter in tracing tests is the selection of the molecules used as water tracers. Many previous tests have failed because of improper selection of these molecules. To address this issue, the first part of this paper provides guidelines, offering data and advice for choosing the best possible tracers for a tracing campaign. This part of the paper presents the different types of water tracers proposed and used in oilfield applications, from the first qualitative tracer study in the 1960s to tracer studies in the 2000s, with their respective advantages and drawbacks. The oil industry began to conduct interwell tracer tests with molecules already successfully used in hydrology. These compounds included radioactive species and stable isotopes, chemicals such as fluorescent dyes, and inorganic ions. Some of the early chemical tracers have been rejected because of issues with adsorption onto the rock. Radioactive species, with a low detection limit, a low reactivity, and a low presence in the environment, have been widely used. However, their use has become more restricted throughout the world in response to the radioactive hazards associated with their use. Therefore, new types of non-radioactive tracers were developed and tested in the 1990s. Currently, however, few chemical molecules possess characteristics matching the selection criteria of an effective water tracer (with regard to environmental and economic aspects, etc.). The most effective molecules currently used as water tracers are the fluorinated benzoic acids (FBA); these molecules can be detected with very low limits of detection (LOD) using analytical techniques such as gas chromatography or ultra-high-performance liquid chromatography coupled with mass spectrometers (GC/MS and UHPLC/MS-MS, respectively).The second part of the paper deals with the analytical aspect of a tracing test. An alternative technique to the fluorescence methods currently used for the naphthalene sulfonic acids (NSA) is proposed: UHPLC/MS-MS. With this original tool, FBA and NSA could be simultaneously detected in water samples in only one 5-min analysis. Other molecules, halogenated boronic acids, were also tested analytically for their potential application as tracers. However, these molecules were not retained because of their overly high LOD, requiring the injection of large quantities into oil reservoirs. © 2012 Elsevier B.V

The Heterogeneous Kinetics of the Reactions ClONO

The kinetics and mechanism of the title heterogeneous halogen exchange reactions of potential atmospheric importance have been studied under molecular flow conditions in a FEP Teflon-coated Knudsen flow reactor on HX (X = Cl, Br, I) - doped ice condensed from the vapor phase under conditions of several formal monolayers of HX coverage at approximately 200 K. In addition, the halogen exchange reactions involving the expected primary reaction products BrCl, ICl and IBr of the above mixed anhydrides with HX-doped ice have been studied at 200 K as well. The uptake coefficient γ for the heterogeneous reaction ClONO2 + HBr on ice is 0.56±0.11 and Cl2 and Br2 are formed in yields of 100% and 66 to 80%, respectively, in the range 180 to 200 K. The γ value for the reaction ClONO2 + HI on ice is 0.30±0.02 at 200 K with Cl2 being the main product appearing after an induction time. The primary product ICl is formed at the same time as Cl2 whereas HOCl appears at a later time under conditions of waning HI supply. The γ value for the reaction BrONO2 + HI on ice is 0.40±0.02 at 200 K with Br2 being the main product observed after a short delay. The primary product IBr is observed without delay, whereas HOBr is observed at a later time once HBr has reacted. The mechanism of the reactions of the interhalogens BrCl, ICl and IBr with HX on ice at 200 K involves the formation of trihalide ions at the ice interface which is consistent with the observed significant negative temperature dependence for the reaction ICl + HBr on ice in the range 180 to 205 K as well as for the reaction BrCl + HBr between 190 and 200 K. The uptake coefficient γ for each of the interhalogens increases from ice to HI-doped ice in the order of increasing molecular weight of HX with the exception of ICl, whose g attains a limiting value of γ = 0.32±0.05. A halogen exchange reaction on ice has been observed in cases where the most stable hydrohalic acid could be formed: HCl > HBr > HI. A propensity for the formation of the homonuclear halogen molecule in the reactions of halogen nitrates with HX-doped ice has been explained by the occurrence of fast secondary reactions of the primary interhalogen product at the HX/ice interface