Traitement de vases de l'estuaire de la Seine

Les sédiments récents et actuels annuellement dragués dans les ports et les estuaires représentent des volumes considérables. Ces boues et ces vases font aujourd'hui l'objet d'un rejet en mer, mais cette procédure est condamnée à court terme. Il est donc nécessaire de réfléchir rapidement à leur nouveau devenir. L'utilisation d'un polymère actif ou d'un ciment CPJ permet de rendre ces boues et ces vases draguées plus cohérentes, en modifiant de manière irréversible leur structure ainsi que leurs propriétés physiques et mécaniques. Le nouvel état physique de ces matériaux apporte un gain immédiat quant aux procédures de transport et de stockage, préalablement à un traitement ou à une utilisation éventuelle

Comparison of 2D simultaneous multi-slice and 3D GRASE readout schemes for pseudo-continuous arterial spin labeling of cerebral perfusion at 3 T

In this perfusion magnetic resonance imaging study, the performances of different pseudo-continuous arterial spin labeling (PCASL) sequences were compared: two-dimensional (2D) single-shot readout with simultaneous multislice (SMS), 2D single-shot echo-planar imaging (EPI) and multishot three-dimensional (3D) gradient and spin echo (GRASE) sequences combined with a background-suppression (BS) module. Whole-brain PCASL images were acquired from seven healthy volunteers. The performance of each protocol was evaluated by extracting regional cerebral blood flow (rCBF) measures using an inline morphometric segmentation prototype. Image data postprocessing and subsequent statistical analyses enabled comparisons at the regional and sub-regional levels. The main findings were as follows: (i) Mean global CBF obtained across methods was were highly correlated, and these correlations were significantly higher among the same readout sequences. (ii) Temporal signal-to-noise ratio and gray-matter-to-white-matter CBF ratio were found to be equivalent for all 2D variants but lower than those of 3D-GRASE. Our study demonstrates that the accelerated SMS readout can provide increased acquisition efficiency and/or a higher temporal resolution than conventional 2D and 3D readout sequences. Among all of the methods, 3D-GRASE showed the lowest variability in CBF measurements and thus highest robustness against noise

Specific features of petrophysical properties of complex carbonate reservoir by complex geophysical data

Актуальность исследования определена необходимостью прогнозирования латеральной изменчивости литологических типов пород, что оказывает влияние на разработку и экономическую оценку месторождения. Очень часто нефтяные компании имеют ограниченный набор геолого-геофизической информации, в связи с чем возникают трудности для прогнозирования перспективных областей, что способствует увеличению неопределенностей при изучении территории месторождения. Цель: выделение и статистическое обоснование фациального строения по данным геолого-геофизической информации на примере одного из месторождений Томской области, приуроченного к палеозойскому фундаменту Западной Сибири. Объектом исследования являются отложения палеозойского фундамента юго-восточной части Западно-Сибирской плиты - коллекторы сложнопостроенных карбонатных толщ, окно исследования, которое охватывает объем горной породы, равный 40 м, выбрано исходя из условий построения сейсмофациальной карты. Методы исследования основаны на использовании комплексного анализа данных - статистическое сопоставление геофизических исследований и кернового материала. Такой анализ способствует уменьшению неопределенностей в процессе оценки и прогноза геологической среды. В работе отмечено, что использование широкого спектра информации влияет на оценку и прогноз распределения геологических тел в пространстве. Предложена методика сравнения акустических свойств, полученных из первоначального источника - сейсмические данные, с расчетными акустическими свойствами по керновым данным. Выявлены взаимосвязи между сейсмической, геофизической информацией и лабораторными исследованиями керна. Обоснование полученной сейсмофациальной карты на основе комплексирования данных позволяет эффективно прогнозировать геологическое распределение фаций в пространстве и времени, но также уменьшать неопределенности при построении геологической модели.The relevance of the research is determined by the need to predict the lateral variability of lithological rock types, which affects the development and economic evaluation of the field. Very often, oil companies have a limited set of geological and geophysical information, in this relation the difficulties arise in predicting promising areas, which contributes to increase in uncertainties in the study of the field. The main aim of the research is isolation and statistical justification of the facies structure according to the geological and geophysical information on the example of one of the deposits of the Tomsk region, confined to the Paleozoic basement of Western Siberia. The object of the study is deposits of the Paleozoic basement of the southeastern part of the West Siberian Plate - complex carbonate reservoir, the study window that covers a rock volume of 40 m is selected based on the conditions for constructing a seismic facies map. Methods of the research are based on the use of integrated data analysis - a statistical comparison of geophysical surveys and core material. This analysis helps to reduce uncertainties in the process of assessing and forecasting the geological environment. The paper notes that the use of a wide range of information affects the assessment and forecast of the distribution of geological bodies in space. A technique is proposed for comparing acoustic properties obtained from the original source - seismic data, with the calculated acoustic properties from core data. The authors have revealed the interconnections between seismic, geophysical information and core research. The justification of the obtained seismic facies map based on the data integration allows us to effectively predict the geological distribution of facies in space and time, but also to reduce uncertainties in the construction of the geological model

Clinical Whole-Brain R2* and Quantitative Susceptibility Maps at 3T -Reproducibility and Parameter Optimization Towards Millimetric 5min Scan

International audienceAdvanced reconstruction techniques allow to jointly estimate R2* and QSM in the brain from multi gradient-recalled echo sequences. This work aims at comparing several protocols in terms of coil setup and acceleration factors using available product sequences and modern hardware. In addition, an automatic and standardized post-processing pipeline is proposed for clinical studies. We show that quantitative values do not differ in terms of head coil, repetition time and acceleration factor used, thus allowing for a millimetric whole-brain coverage within 5 minutes scan time

Clinical Whole-Brain R2* and Quantitative Susceptibility Maps at 3T -Reproducibility and Parameter Optimization Towards Millimetric 5min Scan

International audienceAdvanced reconstruction techniques allow to jointly estimate R2* and QSM in the brain from multi gradient-recalled echo sequences. This work aims at comparing several protocols in terms of coil setup and acceleration factors using available product sequences and modern hardware. In addition, an automatic and standardized post-processing pipeline is proposed for clinical studies. We show that quantitative values do not differ in terms of head coil, repetition time and acceleration factor used, thus allowing for a millimetric whole-brain coverage within 5 minutes scan time