Eor in Western Europe : Status and Outlook

More than sixty EOR projects implemented on the onshore oil fields of Western European countries have been taken into consideration. They cover most of the EOR processes, except the CO2 miscible drive, and several of them have been technically and economically successful. The full list of these projects is given, together with a brief description of six of the most significant among them. The conclusions which can be drawn from the publications on this Western Europe EOR experience are that steam injection remains the most efficient process for very viscous oils. The area of its applicability is the same as that found in other countries of the world, plus a successful extension to heterogeneous fissured reservoirs. Polymer injection in moderately viscous oils is confirmed to be very efficient, provided that improvements in stability of the viscous solution can be obtained. These two processes are the most promising ones on a relatively short term in Western Europe onshore. Considering horizontal drilling as an improved oil recovery technique, some experiences have been gained recently in this method. Since 1980, thirteen horizontal wells have been drilled in Western European oil fields, without taking into account the North Sea area. The first results are quite encouraging, mainly thanks to remarkable improvements in drilling performances. An investigation of the oil potential for EOR shows that 40 to 170 Mm3 of additional oil could be recovered from the currently producing onshore fields in Europe by polymer flooding and up to 75 Mm3 by steam drive, given a favorable oil price assumption. Injection of various gases, under miscible or immiscible conditions, has a theoretical potential that could reach the same magnitude as thermal and polymer processes. However the availability of gas required at cheap conditions makes the development of these reserves improbable. Orientations for research coming from this investigation are in favor of an improvement of the polymer characteristics to ensure and extend their stability over a wider chemical and physical environment. For thermal and gas injection processes, it seems justified to continue efforts to develop foaming agents to reduce instabilities. For longer-term processes such as surfactants, besides some continued efforts still going on to reduce retention of current products, hopes should be placed in possible future development of new, more efficient and cheaper chemicals. Likewise, synergy between horizontal well technique and EOR processes may be expected to raise improved oil recovery to a higher level in the future

Déphosphatation biologique des eaux résiduaires dans une station à boues activées à très faible charge

The operation of the sewage treatment plant for the village of Bavilliers (population 15,000) was modified by the inclusion of an anaerobic zone at the inlet to the aeration tank permit the process of biological phosphorus removal to be studied. The sewage entering the treatment plant was very dilute (BOD5 approximately 150 mg per litre) on account of the high proportion of laundry effluent from a psychiatric hospital in the vicinity, and the treatment plant was operated under conditions of very low organic loading rates (0.04 kg BOD per kg sludge solids.d.). The plant layout also enabled both nitrification and denitrification reactions to occur to an appreciable reactions to occur to an appreciable extent on account of the low sludge loading and the presence of an anoxic zone for denitrification. / L'objet du travail présenté consiste à évaluer et à analyser l'aptitude d'une station à boues activées en sous-charge organique (Cm=0,04 kg DBO5/kg MVS BA.j) recevant des eaux brutes diluées (DBO5 < 155 mg/l) à réaliser une surélimination biologique du phosphore. Le rendement moyen d'extraction du phosphore obtenu est de 40%, les concentrations résiduelles de PT fluctuant entre 2 et 6 mg/l pour des temps de passage dans la zone anaérobie supérieurs à 3 heures (Potentiel rédox <- 50 mV/EHN). Des temps de passage plus longs n'améliorent pas le rendement de déphosphatation mais n'ont pas de conséquences négatives sur l'indice de boues

Intérêt d'une prise de vue cyclopéenne dans un système de transmission d'images de télévision stéréoscopiques

Un système de transmission d'images de télévision stéréoscopiques basé sur une prise de vue à trois caméras: gauche, cyclopéenne et droite est présenté. La caméra cyclopéenne permet d'obtenir directement l'image compatible avec le système standard 2D et une symétrie de qualité entre les images gauche et droite reconstruites pour la visualisation en relief. L'image compatible est transmise avec des données d'assistance, ces données sont constituées de cartes de disparité et d'erreurs d'estimation et permettent de reconstruire les vues gauche et droite à la réception. Le schéma général et le codage des données sont détaillés. Une comparaison avec un système classique comprenant seulement deux caméras est effectuée

Stereochemical aspects of intramolecular palladium catalysed [3+2] cycloadditions of methylenecyclopropanes

The preparation and intramolecular palladium catalysed [3+2] cycloaddition reactions of a range of substrates containing either stereochemically defined 2,3-disubstituted methylenecyclopropanes 3 or acrylate accepters 12-15 are described. Evidence is presented which supports the hypothesis that these cycloaddition reactions proceed via palladium-trimethylenemethane type intermediates and that the two carbon-carbon bonds are formed in a highly asynchronous manner.</p