Cette recherche s'applique uniquement aux ressources en bibliothèque.
32 résultats
Trier par:
Ajouter à la liste:
Étendre à toutes les références (sans texte intégral)
    • Livre
    Sélectionner

    Probability aggregation methods and multiple-point statistics for 3D modeling of aquifer heterogeneity from 2D training images

    Comunian, Alessandro
    Neuchâtel : Université de Neuchâtel, Faculté des sciences
    2011
    Recherche de la disponibilité
    Prêt entre bibliothèques Plus…
    Titre: Probability aggregation methods and multiple-point statistics for 3D modeling of aquifer heterogeneity from 2D training images / Alessandro Comunian
    Auteur: Comunian, Alessandro
    Editeur: Neuchâtel : Université de Neuchâtel, Faculté des sciences
    Date: 2011
    Collation: 228 p. : ill. ; 30 cm
    Note: Thèse Université de Neuchâtel, 2011 - Existe aussi en version électronique
    No RERO: R005928655
    Existe sous différentes formes: Probability aggregation methods and multiple-point statistics for 3D modeling of aquifer heterogeneity from 2D training images
    Permalien:
    http://data.rero.ch/01-R005928655/html

    • Article
    Sélectionner

    Introducing wwhypda a world-wide collaborative hydrogeological parameters database = Introduction à wwhypda

    Comunian, Alessandro
    Renard, Philippe
    Hydrogeology Journal. - 2009/17/2/481-489
    Disponible
    Plus…
    Aucune localisation rattachée
    Titre: Introducing wwhypda a world-wide collaborative hydrogeological parameters database = Introduction à wwhypda
    Auteur: Comunian, Alessandro
    Contributeur: Renard, Philippe
    Sujet: Heterogeneity - Hydraulic properties - Statistical modeling - Tracer tests
    Description: Since the seminal publication of Henry Darcy's work in the 1880s, a very large number of rock property values (such as hydraulic conductivity, permeability, compressibility, porosity, etc.) has been measured and published. These data are, however, dispersed and difficult to access. To overcome this problem and to facilitate site characterization (especially stochastic), a worldwide hydrogeological parameter database (wwhypda) is proposed. It is an open and collaborative catalog allowing users to store and retrieve measurements. The catalog is accessible through a web interface ( http://wwhypda.org ). Presently, it provides individual values and probability density functions of the properties as a function of lithology, scale of observation, location, and geological environment
    Publication en relation: Hydrogeology Journal. - 2009/17/2/481-489
    Document hôte: Hydrogeology Journal
    Identifiant: 10.1007/s10040-008-0387-x (DOI)

    • Article
    Sélectionner

    Introducing wwhypda : a world-wide collaborative hydrogeological parameters database

    Comunian, Alessandro
    Renard, Philippe
    Hydrogeology Journal. - 2009/17/2/481-489
    2009
    Disponible
    Plus…
    Aucune localisation rattachée
    Titre: Introducing wwhypda : a world-wide collaborative hydrogeological parameters database
    Auteur: Comunian, Alessandro
    Contributeur: Renard, Philippe
    Date: 2009
    Sujet: Heterogeneity - Hydraulic properties - Statistical modeling - Tracer tests
    Description: Depuis la publication des travaux originaux de Henry Darcy (datés 1880) de très nombreuses valeurs de propriétés physiques des roches (conductivité hydraulique, perméabilité, compressibilité, porosité, etc.) ont été obtenues expérimentalement et publiées. Ces données sont toutefois dispersées et donc difficiles d’accès. Pour palier à ce problème et pour ainsi faciliter la caractérisation des aquifères (en particulier par des méthodes stochastiques), cet article propose une base de donnée mondiale de paramètres hydrogéologiques. Il s’agit d’un catalogue librement accessible sur Internet (http://wwhypda.org) pour la consultation et la publication des données. Le catalogue contient actuellement des mesures individuelles et permet de calculer des histogrammes des propriétés en fonction de la lithologie, de l’échelle d’observation, de la localisation et de l’environnement géologique.
    Since the seminal publication of Henry Darcy’s work in the 1880s, a very large number of rock property values (such as hydraulic conductivity, permeability, compressibility, porosity, etc.) has been measured and published. These data are, however, dispersed and difficult to access. To overcome this problem and to facilitate site characterization (especially stochastic), a worldwide hydrogeological parameter database (wwhypda) is proposed. It is an open and collaborative catalog allowing users to store and retrieve measurements. The catalog is accessible through a web interface (http://wwhypda.org). Presently, it provides individual values and probability density functions of the properties as a function of lithology, scale of observation, location, and geological environment.
    Desde la publicación originaria del trabajo de Henry Darcy’s en los 1880, una gran cantidad de valores de propiedades de roca (tales como conductividad hidráulica, permeabilidad, compresibilidad, porosidad, etc.) ha sido medidos y publicados. Sin embargo, estos datos están dispersos y son de acceso dificultoso. Para solucionar este problema y facilitar la caracterización de un sitio (especialmente estocástico), se propone una base de datos mundial de parámetros hidrogeológicos (wwhypda). Es un catálogo abierto y colaborativo que permite a los usuarios almacenar y recuperar mediciones. El catálogo está accesible a través de una interfaz web (http://wwhypda.org). Actualmente, provee valores individuales y funciones de densidad de probabilidad de las propiedades en función de la litología, la escala de observación, ubicación y medio geológico.
    Fin dalla publicazione dei primi importanti lavori di Henry Darcy (datati 1880) sono stati misurati e pubblicati moltissimi valori delle diverse proprietà delle rocce (ad esempio conducibilità idrauliche, permeabilità, compressibilità, porosità e così via). Tuttavia questi risultati sono dispersi e di non facile accesso. Per sopperire a queste difficoltà e per fornire uno strumento utile nella caratterizzatione di siti, in particolare dal punto di vista stocastico, si propone una banca dati mondiale di parametri idrogeologici (world-wide hydrogeological parameter database: wwhypda). wwhypda é uno strumento di collaborazione che permette agli utilizzatori di contribuire con i propri dati e/o di consultare liberamente la banca dati, il tutto tramite una interfaccia web (http://wwhypda.org). Singole misure e distribuzioni di probabilità sono fornite e catalogate in funzione della litologia, della scala di osservatione, della localizzazione e dell’ambiente geologico relativi.
    Publication en relation: Hydrogeology Journal. - 2009/17/2/481-489
    Document hôte: Hydrogeology Journal
    Identifiant: 10.1007/s10040-008-0387-x (DOI)

    • Article
    Sélectionner

    Hybrid Inversion Method to Estimate Hydraulic Transmissivity by Combining Multiple-Point Statistics and a Direct Inversion Method

    Comunian, Alessandro, Giudici, Mauro
    Mathematical Geosciences, 2018, Vol.50(2), pp.147-167 [Revue évaluée par les pairs]
    Springer Science & Business Media B.V.
    Disponible
    Plus…
    Titre: Hybrid Inversion Method to Estimate Hydraulic Transmissivity by Combining Multiple-Point Statistics and a Direct Inversion Method
    Auteur: Comunian, Alessandro; Giudici, Mauro
    Sujet: Inverse problem ; Multiple-point statistics ; Direct method ; Heterogeneity ; Training image
    Description: Inversion methods that rely on measurements of the hydraulic head h cannot capture the fine-scale variability of the hydraulic properties of an aquifer. This is particularly true for direct inversion methods, which have the further limitation of providing only deterministic results. On the other hand, stochastic simulation methods can reproduce the fine-scale heterogeneity but cannot directly incorporate information about the hydraulic gradient. In this work, a hybrid approach is proposed to join a direct inversion method (the comparison model method, CMM) and multiple-point statistics (MPS), for determination of a hydraulic transmissivity field T from a map of a reference hydraulic head $$h^\mathrm {(ref)}$$ h ( ref ) and a prior model of the heterogeneity (a training image). The hybrid approach was tested and compared with pure MPS and pure CMM approaches in a synthetic case study. Also, sensitivity analysis was performed to test the importance of the acceptance threshold $$\delta $$ δ , a simulation parameter that allows one to tune the influence of $$h^\mathrm {(ref)}$$ h ( ref ) on the final results. The transmissivity fields T obtained using the hybrid approach take into account information coming from the hydraulic gradient while simultaneously reproducing some of the fine-scale features provided by the training image. Furthermore, many realizations of T can be obtained thanks to the stochasticity of MPS. Nevertheless, it is not straightforward to exploit the correlation between the T maps provided by the CMM and the prior model introduced by the training image, because the former depends on the boundary conditions and flow settings. Another drawback is the growing number of simulation parameters introduced when combining two diverse methods. At the same time, this growing complexity opens new possibilities that deserve further investigation.
    Fait partie de: Mathematical Geosciences, 2018, Vol.50(2), pp.147-167
    Identifiant: 1874-8961 (ISSN); 1874-8953 (E-ISSN); 10.1007/s11004-018-9727-0 (DOI)

    • Plusieurs versions

    High resolution multi-facies realizations of sedimentary reservoir and aquifer analogs

    Bayer, Peter, Comunian, Alessandro, Höyng, Dominik, Mariethoz, Gregoire
    Scientific Data, Jul 2015, Vol.2, p.150033 [Revue évaluée par les pairs]

    • Plusieurs versions

    Locality-based 3-D multiple-point statistics reconstruction using 2-D geological cross sections

    Chen, Qiyu, Liu, Gang, Comunian, Alessandro, Ma, Xiaogang
    Hydrology and Earth System Sciences, 2018, Vol.22(12), pp.6547-6566 [Revue évaluée par les pairs]

    • Article
    Sélectionner

    Three-dimensional high resolution fluvio-glacial aquifer analog - Part 2: Geostatistical modeling

    Comunian, Alessandro
    Straubhaar, Julien, Renard, Philippe, Bayer, P
    Journal of Hydrology. - 2011/405/1/10
    2011
    Disponible
    Plus…
    Aucune localisation rattachée
    Titre: Three-dimensional high resolution fluvio-glacial aquifer analog - Part 2: Geostatistical modeling
    Auteur: Comunian, Alessandro
    Contributeur: Straubhaar, Julien; Renard, Philippe; Bayer, P
    Date: 2011
    Sujet: Multiple-point statistics - Heterogeneity - Hierarchical framework - Aquifer analog - Hydrofacies - Fluvio-glacial
    Description: The heterogeneity of sedimentary structures at the decimeter scale is crucial to the understanding of groundwater flow and transport. In a series of two papers, we provide a detailed analysis of a fluvio-glacial aquifer analog: the Herten site. The geological data along a series of 2D sections in a quarry, the corresponding GPR measurements, and their sedimentological interpretation are described in the companion paper. In this paper, we focus on the three-dimensional reconstruction of the heterogeneity. The resulting numerical model is provided as an electronic supplementary material for further studies. Furthermore, the geostatistical parameters derived from this analysis and the methodology described in the paper could be used in the future for the simulation of similar deposits where less data would be available. To build the 3D model, we propose a hierarchical simulation method which integrates various geostatistical techniques. First, we model the subdivision of the domain into regions corresponding to main sedimentological structures (e.g. a sedimentation event). Within these volumes, we use multiple-point statistics to describe the internal heterogeneity. What is unusual here is that we do not try to use a complex training image for the multiple-point algorithm accounting for all the non-stationarity and complexity, but instead use a simple conceptual model of heterogeneity (ellipsoidal shapes as a training image) and constrain the multiple point simulations within the regions by a detailed interpolation of orientation data derived from the 2D sections. This method produces realistic geological structures. The analysis of the flow and transport properties (hydraulic conductivity and tracer breakthrough curves) of the resulting model shows that it is closer to the properties estimated directly from the 2D geological observations rather than those estimated from a model of heterogeneity based on probability of transitions and not including the modeling of the large-scale structures.
    Publication en relation: Journal of Hydrology. - 2011/405/1/10
    Document hôte: Journal of Hydrology
    Identifiant: 10.1016/j.jhydrol.2011.03.037 (DOI)

    • Article
    Sélectionner

    Analog-based meandering channel simulation

    Mariethoz, Gregoire
    Comunian, Alessandro, Irarrazaval, Inigo, Renard, Philippe
    Water Resources Research. - 2014/50/2/836–854
    Disponible
    Plus…
    Aucune localisation rattachée
    Titre: Analog-based meandering channel simulation
    Auteur: Mariethoz, Gregoire
    Contributeur: Comunian, Alessandro; Irarrazaval, Inigo; Renard, Philippe
    Description: Characterizing the complex geometries and the heterogeneity of the deposits in meandering river systems is a long-standing issue for the 3-D modeling of alluvial formations. Such deposits are important sources of accessible groundwater in alluvial aquifers throughout the world and also play a major role as hydrocarbons reservoirs. In this paper, we present a method to generate meandering river centerlines that are stochastic, geologically realistic, connected, and conditioned to local observations or global geomorphological characteristics. The method is based on fast 1-D multiple-point statistics in a transformed curvilinear domain: the succession in directions observed in a real-world meandering river (the analog) is considered as statistical model for multiple-point statistics simulation. The integration of local data is accomplished by an inverse procedure ensuring that the channels pass through a given set of locations while conserving the high-order spatial characteristics of an analog. The methodology is applied on seven real-world case studies. This work demonstrates the flexibility and the applicability of multiplepoint statistics outside the standard paradigm that considers the simulation of a 2-D or 3-D variable with spatial coordinates.
    Publication en relation: Water Resources Research. - 2014/50/2/836–854
    Document hôte: Water Resources Research
    Identifiant: 10.1002/2013WR013730 (DOI)

    • Article
    Sélectionner

    Three-dimensional high resolution fluvio-glacial aquifer analog - Part 1: Field study

    Bayer, P
    Huggenberger, P, Renard, Philippe, Comunian, Alessandro
    Journal of Hydrology. - 2011/405/1/1
    2011
    Disponible
    Plus…
    Aucune localisation rattachée
    Titre: Three-dimensional high resolution fluvio-glacial aquifer analog - Part 1: Field study
    Auteur: Bayer, P
    Contributeur: Huggenberger, P; Renard, Philippe; Comunian, Alessandro
    Date: 2011
    Sujet: Aquifer analog - Unconsolidated sediment - Digital mapping - Ground penetrating radar (GPR) - Hydrofacies - Heterogeneity
    Description: Describing the complex structures that exist in many sedimentary aquifers is crucial for reliable groundwater flow and transport simulation. However, hardly any aquifer can be inspected in such detail that all decimeter to meter heterogeneity is resolved. Aquifer analogs serve as surrogates to construct models of equivalent heterogeneity, and thus imitate those features relevant for flow or transport processes. Gravel pits found in excavation show excellent sections of the sedimentary sequence and thus offer direct insight into the structural and textural composition of the subsoil. This paper describes an approach to also inspect the third dimension: by mapping during the ongoing excavation it is possible to obtain a three-dimensional representation of the subsurface within a short period of time. A detailed description of a case study is presented and the findings from sedimentological, hydrogeological and geophysical analyses are compared. The gravel pit is located near the town of Herten in southwest Germany, where relatively young unconsolidated fluvio-glacial and fluvial sediments in the Rhine basin are mined. The excavated gravel body is built up by architectural elements typical for braided river deposits. The study generated a high-resolution data set of lithofacies, hydrofacies and ground penetrating radar (GPR) profiles. It represents the basis for a full three-dimensional geostatistical reconstruction presented in the second part.
    Publication en relation: Journal of Hydrology. - 2011/405/1/1
    Document hôte: Journal of Hydrology
    Identifiant: 10.1016/j.jhydrol.2011.03.038 (DOI)

    • Article
    Sélectionner

    Analog-based meandering channel simulation

    Mariethoz, Gregoire
    Comunian, Alessandro, Irarrazaval, Inigo, Renard, Philippe
    Water Resources Research. - 2014/50/2/836–854
    Disponible
    Plus…
    Aucune localisation rattachée
    Titre: Analog-based meandering channel simulation
    Auteur: Mariethoz, Gregoire
    Contributeur: Comunian, Alessandro; Irarrazaval, Inigo; Renard, Philippe
    Description: Characterizing the complex geometries and the heterogeneity of the deposits in meandering river systems is a long-standing issue for the 3-D modeling of alluvial formations. Such deposits are important sources of accessible groundwater in alluvial aquifers throughout the world and also play a major role as hydrocarbons reservoirs. In this paper, we present a method to generate meandering river centerlines that are stochastic, geologically realistic, connected, and conditioned to local observations or global geomorphological characteristics. The method is based on fast 1-D multiple-point statistics in a transformed curvilinear domain: the succession in directions observed in a real-world meandering river (the analog) is considered as statistical model for multiple-point statistics simulation. The integration of local data is accomplished by an inverse procedure ensuring that the channels pass through a given set of locations while conserving the high-order spatial characteristics of an analog. The methodology is applied on seven real-world case studies. This work demonstrates the flexibility and the applicability of multiplepoint statistics outside the standard paradigm that considers the simulation of a 2-D or 3-D variable with spatial coordinates.
    Publication en relation: Water Resources Research. - 2014/50/2/836–854
    Document hôte: Water Resources Research
    Identifiant: 10.1002/2013WR013730 (DOI)