1,720,957 research outputs found
Approccio integrato per l'analisi della subsidenza indotta dalla coltivazione dei giacimenti di idrocarburi
No full textLa variazione della quota altimetrica del piano campagna è imputabile a cause sia naturali sia antropiche. Queste ultime dipendono principalmente dall'emungimento degli acquiferi e dalla coltivazione dei giacimenti di idrocarburi. La verifica che la subsidenza potenzialmente indotta dall'estrazione di fluidi dal sottosuolo non abbia impatto sugli edifici e sulle infrastrutture esistenti nell'area di interesse deve essere condotta valutando sia l'estensione areale del cono di subsidenza sia gli spostamenti massimi. Nel presente articolo viene proposto un approccio numerico 3D per l'analisi dei fenomeni accoppiati fluidodinamici e tenso-deformativi che governano l'evoluzione della subsidenza. Tale approccio si basa sull'integrazione di tre modelli di riferimento: il modello geologico, quello fluido-dinamico e quello geomeccanico. L'approccio di analisi descritto è stato efficacemente adottato per valutare le variazioni altimetriche indotte sul piano campagna dalle attività di uno stoccaggio sotterraneo di gas naturale. L'abbondanza e la qualità delle informazioni disponibili ne facevano un caso studio ideale. L'analisi totalmente integrata ha consentito di ottenere un modello affidabile, come dimostrato dal fatto che il modello è in grado di riprodurre l'evoluzione delle variazioni altimetriche del piano campagna storicamente indotte dalle operazioni di stoccaggio, registrate nel tempo mediante acquisizioni satellitari (misure InSAR)
MONITORING OF CHANNEL RESERVOIRS THROUGH INSAR MEASUREMENTS
No full textChannel sandstones have a particularly important place among sandstone reservoirs. Their exploitation is especially challenging because of the impact of reservoir heterogeneities, channel connectivity and well position. Understanding which channels are drained or swept during water flooding would greatly improve the possibility to increase oil recovery. Although ground movements induced by pressure sinks generated in the reservoir by production are generally very limited, surface deformation is known to reflect the pressure distribution in the reservoir. Thus, deformation monitoring of onshore reservoirs can provide useful information about which portions of the reservoir are actually being produced or where pressure is supported by water encroachment, or by water injection in the case of oil reservoirs. Standard ground surface monitoring techniques (such as: levelling campaigns, tiltmeters or GPS) are usually time-consuming in providing accurate measures for a limited set of benchmarks. However, the
Interferometric Synthetic Aperture Radar (InSAR) has proven to be a cost-effective tool to measure
surface displacement with millimetric precision over wide areas. The possibility to measure surface effects due to reservoir exploitation depends chiefly on the depth and extension of the reservoir, magnitude of pressure depletion within the reservoir, formation heterogeneity and geomechanical properties. This paper presents the results of a study aimed at assessing the effects of these parameters on the surface deformation pattern and magnitude for fluvial reservoirs. Since meandering and braided rivers often generate poorly connected reservoir sand bodies of different size and sinuosity, the approach taken was to build a number of geological models representing fluvial depositional environments at different depths. Then production and water flooding in alternating channels was simulated. Eventually, three-dimensional geomechanical models were developed for each reservoir so as to calculate the vertical and horizontal (longitudinal and transversal) components of the displacements. In order to assess whether these displacements could be detected via InSAR, the three different components of displacement were combined to calculate the Line Of Sight (LOS), to simulate the corresponding satellite displacement measurement; the latter was then compared with the sensitivity of the InSAR technique. Results show that, depending on reservoir depth, extension and pressure decline, a correspondence between the distribution of sand bodies within the reservoir and the surface displacement pattern can be established. Conversely, for the typology of reservoir under analysis, geomechanical properties turn out to play a minor role in the clear detection of surface deformations
Mechanical characterization of gas bearing turbidite sands by CIU/CID triaxial tests in Hoek cell for subsidence effects evaluation
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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