Multiphase Production. Representation of Thermodynamic Properties of Methanol by Different Equations of State

For oil and gas offshore production, any extension of the Multiphase Production Concept to more complex effluents under more difficult transport conditions, requests a better understanding and control of :(a) the thermodynamic behaviour of water-hydrocarbon mixtures,(b) the efficiency of various additives (or mixtures of additives), necessary for a safe, reliable and economical operation of the production and transport facilities. One of the main additives used for hydrate control being methanol, this paper deals specifically with its thermodynamic properties and includes:(a) first, an exhaustive bibliography of experimental-data with the method used for the selection of a coherent and reliable data base,(b) then, a comparison of the results obtained, after adjustement on the data base :- with various cubic and not-cubic equations of state : Peng-Robinson, Cubic-Chain-Of-Rotators (CCOR), Chain-Of-Rotators (COR),- as well as with equations of state including methanol association phenomena (Anderko model, Wenzel and Krop model),(c) and finally, an empirical Bipolynomial equation of state which represents the methanol thermodynamic properties with a good accuracy

Assessing petroleum oils biodegradation by chemometric analysis of spectroscopic data

International audienceThis study was conducted to classify petroleum oils in terms of their biodegradation stage by using spectroscopic analysis associated to chemometric treatments. Principal Component Analysis (PCA) has been applied on infrared and UV fluorescence spectra of Brazilian and Pyrenean oils. For Brazil samples, the method allowed to distinguish the biodegraded oils from the non-affected ones. Pyrenean sampling including oils at different levels of biodegradation has been chosen to follow their alteration rate. PCA loadings have shown spectral regions which have differentiated oils after biodegradation whereas Simple-to-use Interactive Self-Modelling Mixture Analysis (SIMPLISMA) has permitted to obtain a repartition in terms of components families (saturated, aromatic and polar ones) characterizing chemical composition of oils at different biodegradation degrees. Results are in good agreement with conclusions of usual hydrocarbon biomarker analysis

Equilibres de phases dans les systèmes fluides petroliers-eau Phase Equilibria in Oil-Water Systems

Nous présentons quelques résultats obtenus à partir du logiciel FHYD qui permet le traitement des mélanges eau-fluides pétroliers, avec la détermination de la nature des phases (huile-gaz-eau-hydrate) thermodynamiquement stables dans des conditions données de température et de pression, ainsi que de la quantité, de la composition de ces différentes phases et de leurs propriétés. Ce logiciel permet le tracé automatique des diagrammes de phases et nous présentons des exemples, depuis les systèmes binaires (eau-éthane), ternaires (eau-méthane-propane) jusqu'aux fluides les plus complexes. La présence de sels (chlorure de sodium) dissous est envisagée, ainsi que le calcul des conditions de dépôt du sel solide. Des exemples de problèmes pétroliers sont cités (gaz de séparateur saturé en eau, huile saturée en eau dans les conditions de gisement, huile en présence d'eau salée). Les estimations sur les quantités d'hydrate formées et leurs compositions sont comparées à des données expérimentales et aux résultats obtenus par d'autres logiciels. Le programme FHYD pourrait permettre une représentation plus réaliste de l'évolution des fluides pétroliers et des propriétés de transport de leurs différentes phases dans les modèles de simulation des conduites polyphasiques. <br> This article presents a selection of results obtained with the FHYD program. This software allows simulation of mixtures composed of petroleum fluids and water, with determination of the nature of thermodynamically stable phases (oil-gas-water-hydrate) under given conditions of temperature and pressure, along with the quantity, composition and properties of these different phases. Additionally, the program can automatically produce phase diagrams. Several examples of these have been included here, ranging from binary systems (water-ethane) and ternary systems (water-methane-propane) to the most complex petroleum fluids. The presence of dissolved salts (sodium chloride) has also been taken into consideration, as well as the calculation of conditions for the deposition of solid salt. A number of petroleum problems are highlighted: water-saturated separator gas, water-saturated oil in reservoir conditions, and oil in the presence of salt water. Estimates for the quantities and the composition of hydrates formed are compared with experimental data and with results obtained using other software. The FHYD program can serve to give a more realistic representation of petroleum fluid behaviour with more accurate determination of the transportation properties of their different phases, which is essential for the new generation of simulation models for multiphase pipeline design and operation

Comparative Local Case Study of Coniferous Forest Litter of the "Pinus halepensis Mill" in Arid and Semi-arid Areas of Western Algeria

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Comparison of PLS1-DA, PLS2-DA and SIMCA for classification by origin of crude petroleum oils by MIR and virgin olive oils by NIR for different spectral regions

International audienceThis study compares results obtained with several chemometric methods: SIMCA, PLS2-DA, PLS2-DA with SIMCA, and PLS1-DA in two infrared spectroscopic applications. The results were optimized by selecting spectral ranges containing discriminant information. In the first application, mid-infrared spectra of crude petroleum oils were classified according to their geographical origins. In the second application, near-infrared spectra of French virgin olive oils were classified in five registered designations of origins (RDOs). The PLS-DA discrimination was better than SIMCA in classification performance for both applications. In both cases, the PLS1-DA classifications give 100% good results. The encountered difficulties with SIMCA analyses were explained by the criteria of spectral variance. As a matter of fact, when the ratio between inter-spectral variance and intra-spectral variance was close to the F c (Fisher criterion) threshold, SIMCA analysis gave poor results. The discrimination power of the variable range selection procedure was estimated from the number of correctly classified samples

Does land use legacy matter for current soil functioning? A bibliometric study (2001–2020)

International audienceThis article applies the tools of bibliometric analyses to explore the evolution and strategic orientation of research focusing on the temporal dynamics of land use, which can be considered as an important proxy to assess soil vulnerability. With 1416 papers published in 417 different journals, the investigation showed a growing interest in the subject during the period ranging from 2001 to 2020. The main countries working on that topic are the USA, China, and certain countries of the European Union with a worldwide collaboration regarding coauthors. A cluster analysis of the keywords generated 6 main themes of research, each focusing on different issues and approaches, that is, greenhouse gas emissions, soil nutrients, climate change, erosion risk, human disturbances as well as resilience of soil functioning. Finally, it appears that the effect of land use legacy is poorly considered in the context of climate change, which could represent a future line of research