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Статті в журналах з теми "Karstic networks":
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Jaquet, O., P. Siegel, G. Klubertanz, and H. Benabderrhamane. "Stochastic discrete model of karstic networks." Advances in Water Resources 27, no. 7 (July 2004): 751–60. http://dx.doi.org/10.1016/j.advwatres.2004.03.007.
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Somaratne, Nara. "Karst Conduit Networks, Connectivity and Recharge Dynamics of a Sinkhole." Environment and Natural Resources Research 7, no. 3 (September 21, 2017): 70. http://dx.doi.org/10.5539/enrr.v7n3p70.
Анотація:
Management of karst aquifers is often limited by a lack of understanding of recharge and flow dynamics. This article presents the identification of conduit networks and the connectivity, dynamic nature of recharge and inherent uncertainties in recharge assessment in karstic settings. The study was carried out at two large sinkholes located in the Poocher Swamp fresh water lens, south east of South Australia. Point recharge to the sinkholes was calculated using stream flow data at gauging stations and water balance of the swamp. Conduit system and their interconnectivity in the vicinity of sinkholes were characterized by the use of transient electromagnetic survey (TEM) to identify high potential porosity zones of the aquifer. Resistivity data were used to estimate aquifer porosities using Archie’s law. Recharge response to the karstic aquifer was monitored using four monitoring wells located at various distances from sinkholes. Measurements were taken during recharge and recession phases. Four dynamic stages of water level rise and fall were observed in response to filling of conduit zones, transmission and possible effects of entrapped air pressure within conduits. Electrical conductivity (EC) profiles were obtained at two stages. These confirmed interconnectivity of conduits, and re-adjustment to ambient groundwater quality following the recharge event. The lower EC water was found in the monitoring well furthest from the sinkholes indicating the complexity of conduit connection and the nature of mixing with ambient groundwater.
3
Cunha, Lúcio. "O Quaternário, a Morfologia Cársica e o Património Ambiental. Exemplos no sector Setentrional do Maciço de Sicó." Estudos do Quaternário / Quaternary Studies, no. 3 (December 21, 2000): 111–18. http://dx.doi.org/10.30893/eq.v0i3.40.
Анотація:
In the main Portuguese calcareous massifs, the karstic process, which led to the formation of unique landforms and landscapes, nowadays considered of high heritage value, was a long and complex process in which the Quaternary represents only a very small part of the time involved.
Considering only the calcareous massifs of the Westem Portuguese Mesocenozoic Border, if we except the calcareous tufas (and especially the largest outcrop, the Tufas of Condeixa) which were formed well into lhe Quaternary, the karstic forms (Karren, dolines, small caves) that developed there therefore being very recent, in the remaining calcareous rocks the karstic process began in the Jurassic period, and was marked by phases of different intensity at the mercy of tectonic changes, and especially of the successive bioclimatic environments registered in the region. 80th in the Calcareous Massif of Extremedura and in the Sicó Massif the Quaternary seems to have been essentially the setting for the exhumation of paleoforms, some pre-cretaceous, others perhaps tertiary, a1 the same time as a karstic retouching of the calcareous surfaces thus uncovered was taking place.
In spite of this, the most spectacular Landforms, those which have an incontestable heritage value and often correspond to the best known image or these massifs, have the indelible mark of the fluvio-karstic and karstic processes that developed in the Qunternary.
Following the raising of the massifs, and depending on the sandstone coverings progressively mobilized since cretaceous times, which at the beginning of the Quaternary still had, if not a continuous nature, at least larger and thicker extension than the ice remains that can be seen today, conditions were created for the development of the networks of rivers responsible for spectacular canyons, such as, in the case of Sicó, the canyons of Poios, Vale das Buracas and Vale da Grota. Other small canyons, perhaps more worthy of the name, given the almost absolute verticality of their sides, as is the case of the canyon of Rio dos Mouros which was only one of the reasons for the establishment of the Roman city of Conimbriga, despite being perhaps more recent,were born for the same reasons.
An important part of the geological interest of these fluvio-karstic canyons arises from the shape of their sides, and especially from the «buracas», shapes of surface karst which seem to be linked to processes of frost shattering and dissolution under the action of cold climates. Short, almost vertical sectors (the «penas»), openings under rock (the «buracas») and debris of various origins are, without a shadow of doubt, quaternary marks on the sides of the fluvio-karstic canyons and other scarped slopes which contribute a great deal to the valorization of the landscape.
The same is true of formations of two other types, authentic signatures of karstic shaping: the karren, responsible for the «stony desert»)with which classic karst is identified, and the caves which are valuable in themselves because of the beauty they enclose, the challenges they lay down and also, particularly, because of their importance in the process of water circulation and storage. In this case, it was also in the
Quaternary that the responsible processes evolved, for the integral sculpture of many karren formations as for the finishing touches seen in them, this was the time that permitted the final restructuring of the network of galleries wl1ich lay out lhe hydrological functioning of the karst of today.
This article discusses the importance of the processes that took place during the Quaternary in the
construction of the karstic landscape, with particular influence on the formations which, for their genetic specificity, spectacular nature and singularity represent more in terms of environmental heritage.
4
Escobar, Renato Gutierrez, Deane Roehl, Franco Borges Quadros, and Caroline L. Cazarin. "Stochastic modelling of karstic networks of Potiguar Basin, Brazil." Advances in Water Resources 156 (October 2021): 104026. http://dx.doi.org/10.1016/j.advwatres.2021.104026.
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Borghi, Andrea, Philippe Renard, and Sandra Jenni. "A pseudo-genetic stochastic model to generate karstic networks." Journal of Hydrology 414-415 (January 2012): 516–29. http://dx.doi.org/10.1016/j.jhydrol.2011.11.032.
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PETROVIĆ, Aleksandar S., Jelena ĆALIĆ, and Vojkan GAJOVIĆ. "Paleodrainage network reconstruction on Miroč Mt. (Eastern Serbia)." Revista de Geomorfologie 18, no. 1 (November 14, 2016): 69–76. http://dx.doi.org/10.21094/rg.2016.119.
Анотація:
The paper represents a geomorphological study related to the transitional forms between fluvial and karstic process. Karst areas of eastern Serbia are distributed in a large number of relatively isolated segments, and therefore abound in contact karst features. In many cases, central parts of karst areas, away from the contacts, host a variety of relict and dry valleys. Morphological analysis of these valleys may reveal the remnants of paleodrainage networks and help to reconstruct the morphological evolution of the area. This is a case study of the karst of Miroč Mt. in north-eastern Serbia, where geomorphological analysis and relief visualization using the Geomorphological Information System enabled the detection of paleodrainage directions and patterns in the vicinity of the Danube Gorge. Three paleo-river systems were detected, the largest of which is that of the Suva Reka (51 km2).
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Sartégou, Amandine, Didier L. Bourlès, Pierre-Henri Blard, Régis Braucher, Bouchaib Tibari, Laurent Zimmermann, Laëtitia Leanni, Georges Aumaître, and Karim Keddadouche. "Deciphering landscape evolution with karstic networks: A Pyrenean case study." Quaternary Geochronology 43 (February 2018): 12–29. http://dx.doi.org/10.1016/j.quageo.2017.09.005.
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de Rooij, Rob, and Wendy Graham. "Generation of complex karstic conduit networks with a hydrochemical model." Water Resources Research 53, no. 8 (August 2017): 6993–7011. http://dx.doi.org/10.1002/2017wr020768.
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Tamburini, Andrea, and Marco Menichetti. "Groundwater Circulation in Fractured and Karstic Aquifers of the Umbria-Marche Apennine." Water 12, no. 4 (April 7, 2020): 1039. http://dx.doi.org/10.3390/w12041039.
Анотація:
The Umbria-Marche Apennine has a large number of springs that drain water stored in carbonate formations. Spring groundwater constitutes a crucial freshwater resource for many countries, regions, and cities around the world. This study aimed to understand the hydrological mechanisms behind groundwater circulation and their relationship to the structural and stratigraphic settings of specific aquifers. Recession analysis and time series analysis were applied to the daily discharge of six springs monitored over eight years. Both analyses indicated the presence of two types of aquifers: aquifer with unimodal behavior and aquifer with bimodal behavior. The first are characterized by two hydrodynamic sub-regimes, in which fracture networks control the baseflow and conduit networks control the quickflow. In contrast, other springs present only one hydrodynamic sub-regime related to fracture network drainage. Time series analysis confirms the results of recession analysis, showing a large memory effect and a large response time, implying the dominance of the baseflow sub-regime. These results indicate that the Maiolica Formation is characterized by a high degree of fracturation and slight karstification, which control infiltration and percolation, whereas the Calcare Massiccio Formation regulates groundwater circulation in the deeper zones of the aquifer, characterized by a high degree of karstification through moderately developed conduit networks.
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Matislav Majstrović and Hrvoje Olujić. "THE NEUTRAL CONDUCTOR VOLTAGE IN A MEDIUMVOLTAGE NETWORK DURING A GROUND FAULT." Journal of Energy - Energija 57, no. 3 (October 11, 2022): 328–49. http://dx.doi.org/10.37798/2008573327.
Анотація:
Of all the ground faults that can occur in medium-voltage networks from the standpoint of human and equipment safety, the most problematic is a ground fault in a medium-voltage/low-voltage substation. The grounding system of a lowvoltage network is directly connected to the grounding electrode of the substation. Therefore, each increase in the potential of the grounding electrode of the substation is transmitted directly via the neutral conductor into the customer’s installation. For these reasons, in this article a detailed investigation is presented of the problem of determining the neutral conductor voltage in a low-voltage network during a ground fault at the medium-voltage level in a supply substation that is an element of a medium-voltage network with an isolated neutral point (star point). A computer model is presented for the analysis of the neutral conductor voltage in actual distribution networks. Two characteristic distribution networks located on karstic terrain are analyzed. The results obtained are compared to the results of measurements.
Дисертації з теми "Karstic networks":
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Kurtuluş, Bedri. "Modeling of groundwater flow and quality in karstic system using "soft computing" methods (neural networks, fuzzy logic)." Poitiers, 2008. http://www.theses.fr/2008POIT2304.
Анотація:
Karstic aquifers present a great extension throughout the world (12 % of the emerged grounds) and in particular in countries around the Mediterranean sea (from 20 to 90 % of the surface of the Mediterranean countries). These aquifers represent important groundwater potentialities. In both countries (France and Turkey), these karstic aquifers are exploited for drinking water supply and other economic activities (agriculture, pisciculture,. . . ) and constitute the single water resource in certain areas of these countries. The role of these karstic hydrosystems in the social and economical context of some areas is extremely crucial. These aquifers are very vulnerable to contaminations and are overexploited, taking into account the increase in water requirements. Karstic aquifers are very complex and show very particular characteristics (strong heterogeneity, anisotropy, discontinuity of the medium, hierarchization of the flows), which make difficult any classical approach of identification of these systems and management of their water resources. The difficulty of modeling comes owing to the fact that these karstic systems are highly non-linear and are little adapted to the classical methods of identification (flow and transport modeling based on Darcy law). Soft computing methods (Artificial neural networks and fuzzy logic) are playing a key role in the modelling of complex and nonlinear problems. The uncertainty associated with the data, the immense size of the data to deal with, the diversity of the data type and the associated scales are important factors to rely on unconventional mathematical tools such as soft computing. In this thesis, the three pilot experimental sites are: the karst of La Rochefoucauld in France which is used in particular for the supply of the regional capital Angouleme; Orbe karstic spring which supplies the rural city of Arette (Southwestern France) and the karst of Safranbolu in Turkey which supplies the town of Safranbolu. The principal objective of this work is to test the ability of soft computing methods for modeling of complex karstic systems and predicting the discharge rates and quality of water at the outlets of these systems. The results show the ability of Soft computing method to model these highly non linear systems. All the modelling work was carried out using the Matlab programming environmentLes aquifères karstiques présentent une grande extension à travers le monde (12 % des terres émergées) et notamment dans les pays du pourtour méditerranéen (de 20 à 90 % de la surface des pays méditerranéens). Ces aquifères représentent d’importantes potentialités en eau souterraine. Dans les deux pays concernés (France et Turquie), ces aquifères karstiques sont exploités pour l’alimentation en eau potable et pour d’autres activités économiques (agriculture, pisciculture, …) et constituent parfois l’unique ressource en eau dans certaines régions de ces pays. Le rôle des hydrosystèmes karstiques dans le développement social et économique de telles régions est de ce fait extrêmement crucial. Ces aquifères sont cependant très vulnérables aux contaminations et font l’objet de surexploitation, compte tenu de l’accroissement des besoins en eau. Les aquifères karstiques sont très complexes et présentent des caractéristiques très particulières (forte hétérogénéité, anisotropie, discontinuité du milieu, hiérarchisation des écoulements) qui rendent difficile toute approche classique d’identification de ces milieux et de gestion de leurs ressources en eau. La difficulté de modélisation provient du fait que ces systèmes karstiques sont hautement non-linéaires et sont peu adaptés aux méthodes d’identification classiques (modélisation des flux d’eau et de matière basée sur la loi de Darcy). L’objectif principal de cette thèse est la modélisation de ces systèmes à l’aide d’approches nouvelles (méthodes de ‘soft computing’) dans le but de prédire les flux et la qualité des eaux dans ces systèmes. Les systèmes retenus sont : le karst de La Rochefoucauld en France qui est utilisé notamment pour l’alimentation de la capitale régionale Angoulême ; Le karst de l’Orbe qui est utilisé pour la ville d’Arrete et le karst de Safranbolu en Turquie qui alimente la ville de Safranbolu. Dans cette thèse, les points suivants sont étudiés :Installation, calibrage des systèmes d'enregistrement des données (data logger) et contrôle des sondes, Recherche sur les différents types de systèmes karstiques (La Rochefoucauld et Orbe en France et Safranbolu en Turquie, Détermination de la pluie efficace sur le karst de Safranbolu en utilisant des données hydrométéorologiques (y compris la neige). Interprétation des données des enregistreurs automatiques et des analyses chimiques effectuées en laboratoire pour mieux comprendre le fonctionnement du karst, Développement des modèles ‘soft computing’ (réseaux de neurone et neuro-floue) concernant les 3 systèmes karstiques étudiés. Discussion sur les méthodes (réseaux de neurone et neuro–flou) et les calibrages des modèles. Comparaison des modèles avec entrée simple et entrées multiples. Détermination des propriétés faibles et fortes de ces modèles. Les conclusions obtenues sont les suivantes :Les corrélations entre débits simulés et débits observés sont élevées pour le karst de La Rochefoucauld. Le coefficient de détermination pour la phase d’apprentissage est élevé (R2=0. 90). Les hydrogrammes permettent de se rendre compte que l’apprentissage et la validation des modèles sont tout à fait opérationnels, puisqu’on remarque que les parties montantes des hydrogrammes simulés correspondent bien à de fortes pluies. De plus la forme des hydrogrammes simulés (montée rapide, suivie d’une décrue assez lente) est semblable à celle des hydrogrammes réels de sources d’aquifères karstiques (Voir Figure 4. 8). Les données de pluie utilisées concernent la pluie brute, sans transformation en pluie efficace, ce qui permet de s’affranchir de certaines hypothèses simplificatrices non vérifiables pour l’aquifère de La Rochefoucauld. Par contre nous avons retenu la pluie efficace comme entrée des modèles du karst de Safranbolu. L’effet de la fonte de neige et une correction de certaines données par rapport à l’altitude ont été intégrées dans l’évaluation de la pluie efficace. Les modèles ‘soft computing’ pluie - qualité de l’eau (Turbidité, Conductivité électrique) ont été développés. Pour les modèles neuro-flous la phase d’apprentissage est beaucoup plus lente et nécessite un moyen de calcul puissant. Les modèles hybrides (neuro-flous) sont plus efficaces que les modèles de réseaux de neurones. Les modèles neuro-flous ont un coefficient de détermination plus élevé que les modèles de réseaux de neurones (Voir Table 4. 5). Les variables d’entrée ont une très grande importance dans le développement des méthodes ‘soft computing’. En augmentant les données d’entrée, les modèles peuvent calculer de meilleurs résultats. Ainsi, les modèles avec deux variables d’entrées sont caractérisés par un coefficient de détermination plus élevé que les modèles à une variable d’entrée. En outre, pour la prédiction des valeurs extrêmes, les modèles avec entrées multiples sont plus efficaces que les modèles à entrée simple (Voir Table 4. 9). Pour les aquifères karstiques d’Orbe et de Safranbolu, la prédiction des paramètres hydrochimiques (conductivité électrique et turbidité) à été egalement modelisée à l’aide des méthodes ‘soft computing’. Les résultats montrent que la forme des chemogrammes simulés est semblable à celle des chemogrammes réels (Voir Figures 5. 19, 5. 22, 5. 25, 5. 27, 5. 28, 5. 29, 5. 30). Par contre, on constate aussi que pour obtenir des prédictions plus longues, le modèle aura besoin de séries de données plus longues. Ainsi, les résultats obtenus sont très encourageants et permettent d’envisager des perspectives intéressantes et nouvelles de modélisation des aquifères karstiques, qui sont des systèmes hautement non-linéaires
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Sartégou, Amandine. "Évolution morphogénique des Pyrénées orientales : apports des datations de systèmes karstiques étagés par les nucléides cosmogéniques et la RPE." Thesis, Perpignan, 2017. http://www.theses.fr/2017PERP0044/document.
Анотація:
Les Pyrénées ne sont pas considérées comme une chaîne active malgré certaines évidences néotectoniques et la microsismicité. Toutefois, des travaux récents ont montré que la chaine n’avait probablement jamais atteint un état stationnaire. Or, le soulèvement tectonique des chaînes de montagnes actives contrôle a priori les rythmes et les taux d’incision des vallées fluviales, lesquels sont à leur tour modulés par les changements climatiques répétés du Quaternaire. Une option pour contraindre les mouvements verticaux à long terme est de quantifier les taux d’incision par le biais de marqueurs géométriques passifs du soulèvement tels que les terrasses alluviales. Mais, selon les contextes, il n’est pas toujours possible de contraindre le soulèvement à partir de tels marqueurs. Les réseaux karstiques constituent une alternative du fait de la possibilité de déterminer la durée d’enfouissement d’alluvions fluviatiles provenant de la partie amont des bassins versants et piégés lors de leur traversée des chaînons calcaires périphériques à partir de la concentration en nucléides cosmogéniques produits in situ dans leur fraction quartzeuse. En effet, au fur et à mesure de l’encaissement de la vallée, différentes générations de conduits épinoyés horizontaux se mettent en place, les réseaux plus récents se formant en-dessous des générations précédentes. Ces galeries étagées enregistrent les paléo-altitudes des paléo-niveaux de base locaux. Ainsi, dès lors qu’elles piègent des alluvions fluviatiles, les galeries épinoyées sont assimilables à des niveaux de terrasses alluviales.Nous avons déterminé les durées d’enfouissement de sédiments détritiques dans 61 cavités des vallées de la Têt, de l’Ariège, de l’Aude et de l’Agly, via les méthodes 26Al/10Be et 10Be/21Ne, en sus d’observations morphologiques (développement des réseaux, analyse des étagements). Ces vallées offrent des étagements conséquents et les fleuves qui les parcourent sont connectés à des niveaux de base distincts (façades Atlantique et Méditerranéenne). Les résultats sur ces vallées nous permettent de documenter des incisions du Miocène ancien (~16-13 Ma) jusqu’à l’actuel avec des influences de forçages externes et de l’eustatisme que nous analyserons. L’extrapolation des taux d’incision permet également d’estimer des âges Oligo-Miocène pour les surfaces perchées incisées par ces systèmes fluviatiles.Cependant, la densité de paléo-drains sub-horizontaux sur une tranche altimétrique (relativement à la précision des techniques de datations), le contexte géodynamique, voire paléoclimatique, les réorganisations des réseaux de drainage, peuvent engendrer des histoires de remplissages des réseaux plus complexes qu’escomptées. De ce fait, contraindre justement et précisément l’âge d’un dépôt, même via des croisements inter-méthodes (26Al/10Be, 10Be/21Ne, RPE, OSL) peut s’avérer infructueuxThe rates and chronologies of valley incision are closely modulated by the tectonic uplift of active mountain ranges and were controlled by repeated climate changes during the Quaternary. The continental collision between the Iberian and Eurasian plates induced a double vergence orogen, the Pyrenees, which has been considered as a mature mountain range in spite of significant seismicity and evidence of neotectonics. Nevertheless, recent studies indicate that the range may have never reached a steady state. One option for resolving this controversy is to quantify the incision rates since the Miocene by reconstructing the vertical movement of geometric markers such as fluvial terraces. However, the few available ages from the Pyrenean terrace systems do not exceed the middle Pleistocene. Thus, to enlarge the time span of this dataset, we studied alluvium-filled horizontal epiphreatic passages in limestone karstic networks. Such landforms are used as substitutes of fluvial terraces because they represent former valley floors. They record the transient position of former local base levels during the process of valley deepening. In addition to morphological observations, the burial durations of detrital sediments in 61 cavities of the Têt, Ariège, Aude and Agly valleys were determined using cosmogenic 26Al/10Be and 10Be/21Ne ratios. The results obtained allow us to document incision processes since the early Miocene (~ 16-13 Ma) and to study influences of external forcing and eustatism. In comparison with other studies, it appears that incision rates are probably higher in the central Pyrenees, suggesting an increased role for glaciers in the incision process. Moreover, a gradient would also be observable from north to south, the Spanish slope probably having been incised faster. However, the density of sub-horizontal levels on an elevation range, the geodynamical and paleo-climatic contexts, the reorganization of the drainage networks may lead to networks filling stories more complex than expected. The obtained results applying various suitable geochronological methods (26Al/10Be, 10Be/21Ne, ESR and OSL on quartz) sometimes evidence that these radiometric approaches may be limited when source and/or emplaced deposits are reworked. The validity of dosimetric methods in a mountainous context, and the possibility that not all of the quartz grains are bleached at the time of deposition will also be discussed
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Frantz, Yves. "Simulation stochastique des réseaux karstiques." Electronic Thesis or Diss., Université de Lorraine, 2021. http://www.theses.fr/2021LORR0215.
Анотація:
Difficiles d'accès, les réseaux karstiques ne sont généralement que partiellement décrits. Les techniques d'exploration classiques produisent par ailleurs des données éparses et sujettes à des incertitudes concernant la position des conduits et leurs dimensions, paramètres essentiels aux simulations d'écoulement. Les simulations stochastiques permettent de mieux gérer et évaluer ces incertitudes en proposant plusieurs représentations équiprobables de systèmes karstiques. Le simulateur idéal devrait permettre de construire des réseaux de drains karstiques tridimensionnels, honorant les observations de terrain (indices de karstification), les connaissances apportées par les essais de traçage, les informations recueillies sur des parties accessibles du réseau et celles apportées par l'étude d'autres réseaux. C'est dans ce contexte que s'inscrit cette thèse qui propose 3 principales contributions. La première contribution est l'analyse statistique d'une base de données de 49 réseaux karstiques. Elle se focalise sur l'étude de la géométrie des conduits, à travers l'analyse de deux métriques : le rayon équivalent et le ratio largeur-hauteur. Aucune loi statistique générique qui décrirait la géométrie des conduits n'a pu être mise en évidence. Néanmoins, la variabilité spatiale des propriétés géométriques à différentes échelles a été caractérisée, notamment grâce au développement de variogrammes 1D-curvilinéaires. L'hypothèse répandue d'une organisation hiérarchique des géométries de conduits a également été analysée et rejetée. La deuxième contribution est le développement de deux méthodes de simulation stochastique de propriétés le long de réseaux karstiques s'appuyant sur les résultats de l'analyse statistique. La première méthode se focalise sur la reproduction de la variabilité des propriétés à l'échelle du réseau, tandis que la deuxième se concentre sur la reproduction de la variabilité au sein et entre les branches du réseau.Elles sont toutes deux basées sur les méthodes de Simulations Gaussiennes Séquentielles (SGS), ici adaptées à des objets 1D-curvilinéaires. La troisième contribution est le prototype d'une méthode ayant pour but de simuler stochastiquement des réseaux karstiques discrets sous forme de graphes (qualifiés de squelettes des réseaux). Il est espéré qu'une fois entièrement développée, elle permette de simuler différents types de réseaux et de prendre directement en compte les données de terrain ainsi que les informations géologiques. Elle consiste en trois grandes étapes : i) la génération d'un nuage de points, ii) le calcul de leur connectivité et iii) leur connexion pour former le squelette du réseau karstique. Ces contributions ouvrent de nouvelles perspectives quant à la simulation de réseaux de drains karstiques utilisables pour la simulation d'écoulement (e.g., SWMM, Epanet, Modflow-CFP), ce qui devrait permettre une meilleure caractérisation des flux en leur seinDespite intensive explorations by speleologists, karstic networks remain only partially described as many conduits are not accessible to humans. The classical exploration techniques produce sparse data subject to uncertainties concerning the conduit position and their dimensions, which are essential parameters for flow simulations.Stochastic simulations make it possible to better handle and assess these uncertainties by offering several equally probable karstic system representations.The ideal simulator should allow for the construction of tridimensional karstic drain networks, respecting the field observations (karstification markers), the knowledge brought by tracer tests, the information collected in the accessible parts of the network and those obtained by the study of other networks.In this context, this PhD thesis offers 3 main contributions.The first contribution is the statistical analysis of a database of 49 karstic networks.It focuses on the study of conduit geometry, through the analysis of two metrics : the equivalent radius and the width-height ratio.No generic statistical law describing the network geometry was found.Nonetheless, the spatial variability of the geometrical properties at different scales was characterized, mostly through the development of 1D-curvilinear variograms.The widespread hypothesis of a hierarchical organization of the conduit geometries has also been analysed and rejected.The second contribution is the development of two methods allowing stochastic simulations of properties along karstic networks and based on the results of the statistical analysis. The first method focuses on the reproduction of the property variability at the network scale, while the second one focuses on the reproduction of the variability within and between the network branches.Both are based on the Sequential Gaussian Simulation methods and are adapted to 1D-curvilinear objects.The third contribution is the prototype of a method aiming to stochastically simulate discrete karstic networks as graphs (known as network skeletons}). We hope that once completed, it would allow the simulation of different network types, while taking directly into account field data and geological information. It is divided in three main steps : i) the generation of a point cloud, ii) the computation of the point connectivity and iii) their connection to create the skeleton of the karstic network.These contributions open new prospects regarding the simulation of karstic drain networks usable for flow simulation (e.g., SWMM, Epanet, Modflow-CFP), which should allow a better characterization of the associated flows
4
Jazayeri, Noushabadi Mahmoud Reza. "Characterisation of relationships between fracture network and flow-path network in fractured and karstic Reservoirs : Numerical modelling and field investigation (Lez aquifer, Southern France)." Montpellier 2, 2009. http://www.theses.fr/2009MON20206.
Анотація:
Bien que le comportement et la modélisation des écoulements dans les réservoirs fracturés constituent une problématique de recherche abordée depuis le milieu des années soixante, la caractérisation des réservoirs fracturés soulève encore de nombreuses incertitudes. Dans le contexte du développement et de l'exploitation des réservoirs fracturés, le problème principal le plus souvent cité comprend la définition des propriétés du réseau de fractures qui détermine le réseau d'écoulement ainsi que les modalités de l'écoulements inter-porosité. L'essai de puits est l'un des outils le plus utilisé pour caractériser les propriétés géométriques et hydrodynamiques des réservoirs fracturés sur la base de solution analytique simple. La considération d'une solution analytique de type double porosité pour l'interprétation de l'essai de puits permet ainsi de renseigner le coefficient d'échange inter-porosité, ainsi que le rapport entre les propriétés hydrodynamiques des fractures et celles du réservoir. Ces informations, qui concernent un réservoir fracturé donné, sont généralement issues de l'interprétation, à l'échelle régionale, de la réponse hydrodynamique obtenue sur quelques puits seulement. Néanmoins, tous les puits d'observation n'ont pas la même réponse hydrodynamique à un essai de puits ; ceci pose la question de l'impact de la localisation du puits de pompage et du piézomètre sur la détermination des propriétés hydrodynamiques du réservoir lors de l'interprétation de l'essai de puits. Pour évaluer les différents effets liés à l'emplacement du puits de pompage sur la réponses hydrodynamique, une série d'essais de puits a été simulée dans des réseaux de fractures synthétiques et leur réponse hydrodynamique a été interprétée à l'aide d'un modèle de type double porosité L'impact de la localisation du puits de pompage et des propriété géométriques du réservoir fracturé, telles que l'espacement et la longueur des fractures, sur le comportement des écoulements et la valeur du coefficient d'échange inter-porosité est examiné dans le premier chapitre. Dans le deuxième chapitre, la relation entre réseau de fractures et réseau d'écoulement est examinée dans le cas d'un aquifère fracturé et karstique (aquifère du Lez), en considérant le comportement hydrodynamique à l'échelle locale et le comportement hydrodynamique à l'échelle régionale. De cette façon, sont appréhendés les paramètres principaux qui conditionnent le réseau d'écoulement préférentiel, et ses liens avec le réseau de fractures. Différentes propriétés géométriques, telles que la densité, l'orientation, et la longueur des fractures sont déterminées à différentes échelles : échelle du puits, échelle locale (site expérimental), et échelle régionale (aquifère). A cette fin, différentes techniques d'acquisition (imagerie de puits, mesures à l'affleurement, photographie aérienne) sont utilisées pour caractériser la fracturation. Des mesures géophysique réalisées à l'échelle locale (site expérimental) permettent d'obtenir des cartes de résistivité 2D et 3D qui illustrent la grande hétérogénéité du site, caractéristique des réservoirs fracturés. L'investigation du réseau d'écoulement est réalisée au moyen de diagraphies de puits, de tests d'interférences et de tests d'impulsions, à l'échelle locale et à l'échelle régionale. Ces différents outils nous renseignent sur la connectivité des différents puits avec le réseau d'écoulement ainsi que sur les propriété hydrodynamiques de différentes zones du réservoir fracturé. Dans le troisième chapitre, un modèle hydrogéologique conceptuel est proposé à l'échelle locale et à l'échelle régionale. Ces modèles servent de fondement à deux modèles numériques 2D basé pour voir si la geomodélisation numérique et les résultats de simulation d'écoulements de fluides confirment notre hypothèse intégrée dans les modèles conceptuelsAlthough the specific flow behaviour of fractured reservoirs has been identified and modelled since relatively long time, there are still lots of problem concerning the fractured reservoir characterisation. The main problem, often cited in the context of the development and exploitation of fractured reservoirs, is the difficulty in defining the fracture network properties that impact the flow path-network and the inter-porosity flow transfer between the fracture continuum and matrix continuum. Well test is one of the tools that are used for the characterisation of geometrical and hydrodynamic properties of fractured reservoir, such as inter-porosity flow exchange coefficient, fracture storativity to whole reservoir storativity ratio, and reservoir permeability. But all these information applied to characterise a fractured reservoir at regional scale are inferred from only a few boreholes. One may thus wonder if all observation boreholes have the same hydrodynamic response to a well test. In order to answer this question a series of numerical well tests are conducted in synthetic fracture networks to evaluate the effect of the pumping well location on the dual porosity pressure responses. The impact of geometrical parameters, such as fracture spacing and mean length, on fluid flow behaviour and inter-porosity exchange coefficient are investigated for different pumping well location in the first chapter. Well test simulations in the synthetic fractured reservoirs, with a non uniform distribution pattern, highlight the dependency of the measured inter-porosity flow exchange coefficient to the pumping test location. The mean fracture length (which controls connectivity) is assessed to be the main geometrical parameter which influences the reservoir hydrodynamic response during well test. In the second chapter, the relationship between fracture network and flow-path network are investigated in a real fractured and karstic carbonate aquifer (Lez aquifer, southern France). A multi-disciplinary case study, which aims to assess the main parameters which affect the preferential flow-path network, is thus performed. It comprises geological, geophysical and hydrodynamic data acquisition and interpretations. The collection of geometrical parameters such as fracture density, orientation, length is done at different scales (borehole, field site, aquifer). Applying different data acquisition techniques such as borehole image, outcrop observation and aerial photography are claimed to characterise the fracture network. In this experimental part, it is shown that geological and geophysical data such as fracture data acquisition, borehole imagery (OTV), reservoir electrical resistivity imaging are the minimum requested data for characterizing the fracture network of a given reservoir. Investigation of flow-path network is done through conducting a series of well logging, interference tests and pulse tests at two scales. This step gives some clarifications about the quality of connectivity and conductivity of fractures at different zones. Then, we assess the relationship between fracture network and flow-path network by integrating all geological, geophysical and hydrodynamic data. It is shown that conducting well test series at two different scales within the same fractured and karstic reservoir allow verifying the scale dependency of permeability within a same system; it also shows that other important factors than the scale of observation affect these permeability variations. Combination of all data (geological, geophysical and hydrodynamic) illustrates that the borehole connectivity to the flow-path network and water table level during well test operation are the parameters which mainly control the permeability value estimation, whatever the scale of observation. Finally, in the third chapter, we define the hydrogeological conceptual models at local and regional scales. Then a simple 2D numerical model based on the hydrogeological conceptual model at each scale is proposed and the numerical geomodelling and fluid flow simulation are compared to the observed hydrodynamic behaviour in the site. Results of fluid flow simulation in the numerical models at local and regional scales confirm our hypothesis about effect of borehole location and its connectivity with the flow-path network on the recorded hydrodynamic responses at borehole
5
Kong, A. SIou Line. "Modélisation des crues de bassins karstiques par réseaux de neurones. Cas du bassin du Lez (Hérault)." Thesis, Montpellier 2, 2011. http://www.theses.fr/2011MON20070/document.
Анотація:
Les karsts sont l'une des formations aquifères les plus présentes au monde. Exploités, ils fournissent de l'eau potable pour près de 25% de la population mondiale. Cependant la forte hétérogénéité de leur structure implique un comportement non-linéaire et les rendent particulièrement difficiles à étudier, à simuler et à prévoir. Les réseaux de neurones formels sont des modèles d'apprentissage statistiques qui ont été largement utilisés en hydrologie de surface depuis les années 1990, grâce à leurs propriétés de parcimonie et d'approximation universelle.Dans cette thèse, il est proposé d'utiliser les réseaux de neurones pour étudier le comportement des aquifères karstiques. L'aquifère du Lez est choisi pour appliquer le modèle par réseaux de neurones. Cet aquifère, situé près de l'agglomération de Montpellier (400 000 habitant), est exploité pour fournir de l'eau potable à une grande partie de l'agglomération.Dans un premier temps, un réseau de neurones « classique », de type boîte noire, est appliqué à la simulation et à la prévision des débits de la source du Lez. Une méthode de sélection des entrées de pluie est proposée, couplant analyse par corrélations croisées et méthode de validation croisée. Les résultats montrent l'adéquation du modèle neuronal pour la simulation et la prévision du débit de la source d'un aquifère karstique complexe. Le test du modèle est effectué sur les deux cycles hydrologiques comportant les crues les plus intenses de la base de données. Les hydrogrammes montrent que le modèle neuronal a été capable d'extrapoler puisque les débits prévus pour les crues majeures en test sont corrects et supérieurs aux débits présents dans la base d'apprentissage du modèle. La prévision est acceptable jusqu'à un horizon de prévision de un jour. Dans un second temps, une méthode d'extraction des données contenues dans la boîte noire est proposée. Afin de contraindre le modèle neuronal à donner des valeurs physiquement interprétables, des connaissances a priori sur la géologie de l'aquifère sont incluses dans l'architecture du réseau de neurones. La méthode KnoX (Knowledge eXtraction) proposée dans cette étude permet d'extraire du modèle les contributions des différentes zones géologiques à la source du lez ainsi que les temps de réponse correspondants. L'application de la méthode KnoX a un hydrosystème fictif dont on contrôle en particulier les temps de réponse et les contributions des différents sous-hydrosystèmes fictifs a permis de valider cette méthode. Les résultats obtenus sur le bassin du Lez sont très satisfaisants et en adéquation avec les connaissances actuelles que l'on a sur ce système. De plus la méthode a permis d'affiner ces connaissances, notamment l'infiltration retardée par des aquifères perchés et concernant la limite du bassin d'alimentation de la source du Lez. Enfin, la méthode KnoX est générique et applicable à tout hydrosystème pour lequel on dispose de mesures de pluie et de débitKarst is one of the most widespread aquifer formations in the worlds. Their exploitation provides fresh water to practically 25% of the global population. The high level of structure heterogeneity in these aquifers however makes them complex and their behavior is difficult to study, simulate and forecast.Artificial neural networks are machine learning models widely used in surface hydrology since the 90's thanks to their properties of parsimony and universal approximation.In this thesis, artificial neural networks are used to study karst aquifer behavior. Application is done in the Lez. This aquifer situated near Montpellier conurbation (400 000 inhabitants) provides fresh water for a large part of this population.First, a “classical” black box neural network is applied to simulate and forecast Lez spring discharge. A rainfall input selection method is proposed, using cross correlation analysis and cross validation method at the same time. Results show neural model efficiency in order to simulate and forecast the spring discharge of a complex karstic aquifer. The model was tested using two hydrologic cycles including the two most intense floods of the database. Hydrographs shows that neural model was able to extrapolate the maximum flood discharge of the learning database. Forecasting is satisfactory until a one-day horizon.In a second time, extraction of the knowledge data included in the black box is proposed. In order to constrain the model to give physically plausible solution, a priori knowledge about aquifer geology is included into the network architecture. KnoX (Knowledge eXtraction) method proposed in this study aims at extract geological zone contributions to the Lez spring and corresponding response times. The KnoX methodology was applied to a fictitious hydrosystem built using a model with controlled parameters, in particular contributions of subbasin to the outlet and lag time of each subbasin. This application permitted to validate the KnoX methodology. Results obtained on the Lez basin are satisfactory and agree with current knowledge about this hydrosystem. In addition, the KnoX methodology allows to refine this knowledge, in particular concerning delayed infiltration because of infiltration in perched aquifer and concerning Lez spring alimentation basin boundaries. Lastly the KnoX methodology is a generic methodology that can be applied on any basin with available discharge and rainfall data
6
Taver, Virgile. "Caractérisation et modélisation hydrodynamique des karsts par réseaux de neurones : application à l'hydrosystème du Lez." Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20169/document.
Анотація:
La connaissance du fonctionnement hydrodynamique des karsts représente un enjeu planétaire pour la ressource en eau car ils alimentent en eau potable près de 25% de la population mondiale. Néanmoins, la complexité, l'anisotropie, l'hétérogénéité, la non-linéarité et l'éventuelle non-stationnarité de ces aquifères en font des objets encore largement sous-exploités du fait de la difficulté de caractériser leur morphologie et leur fonctionnement hydrodynamique. Dans ce contexte, le paradigme systémique permet d'apporter de nouvelles méthodes en étudiant ces hydrosystèmes au travers de la relation entre leurs signaux d'entrée (pluie) et de sortie (débit). Ainsi ce travail porte sur l'utilisation : i) d'analyses corrélatoires et spectrales pour caractériser la réponse des hydrosystèmes karstiques, ii) des réseaux de neurones pour étudier les relations linéaires et non-linéaires de ces hydrosystèmes. Pour ce faire, différents types de configuration de modèles par réseau de neurones sont explorés afin de comparer le comportement et les performances de ces modèles. On cherche à contraindre ces modèles pour les rendre interprétables en terme de processus hydrodynamiques en rapprochant le fonctionnement du modèle à celui du système naturel afin d'obtenir une bonne représentation et d'extraire des connaissances à partir des paramètres du modèle.Les résultats obtenus par les analyses corrélatoires et spectrales permettent d'orienter la configuration des modèles de réseaux de neurones. Appliqués à l'hydrosystème du Lez sur la période 1950-1967, les résultats montrent que les réseaux de neurones sont à même de modéliser les hydrosystèmes au fonctionnement non-linéaires. L'utilisation de deux hydrosystèmes variant dans le temps (la Durance en France et Fernow aux USA) tend à souligner la capacité des réseaux de neurones à modéliser efficacement les systèmes non stationnaires. Des méthodes d'ajustement en temps réel (adaptativité et assimilation de données) permettent d'accroître les performances des modèles par apprentissage statistique face à des modifications des entrées ou du système lui-même.Finalement, ces différentes méthodes d'analyse et de modélisation permettent d'améliorer la connaissance de la relation pluie-débit. Les outils méthodologiques réalisés dans cette thèse ont pu être développés à partir de l'application à l'hydrosystème du Lez dont le fonctionnement est étudié depuis des décennies. Cette méthodologie d'étude et de modélisation présente l'avantage d'être transposable à d'autres systèmesImproving knowledge of karst hydrodynamics represents a global challenge for water resource because karst aquifers provide approximately 25% of the world population in fresh water. Nevertheless, complexity, anisotropy, heterogeneity, non-linearity and possible non-stationarity of these aquifers makes them underexploited objects due to the difficulty to characterize their morphology and hydrodynamics. In this context, the systemic paradigm proposes others methods by studying these hydrosystems through input-output (rainfall-runoff) relations.This work covers the use of: i) correlation and spectral analysis to characterize response of karst aquifers, ii) neural networks to study and model linear and non-linear relations of these hydrosystems. In order to achieve this, different types of neural networks model configurations are explored to compare behavior and performances of these models. We are looking to constrain these models to make them interpretable in terms of hydrodynamic processes by making the operation of the model closer to the natural system in order to obtain a good representation and extract knowledge from the model parameters.The results obtained by correlation and spectral analysis are used to manage the configuration of neural networks models. Applied on the Lez hydrosystem over the period 1950-1967, results show that neural networks models are capable to model non-linear operation of the karst.Application of neural modelling on two non stationary hydrosystems (Durance in France and Fernow in the the USA) proved the ability of neural networks to model satisfactorily non-stationary conditions. Moreover, two real-time adjustment methods (adaptativity and data assimilation) enhanced the performance of neural network models face to changing conditions of the inputs or of the system itself.Finally, these various methods to analyze and model allow improving knowledge of the rainfall-runoff relationship. Methodological tools developed in this thesis were developed thanks to the application on Lez hydrosystem which has been studied for decades. This study and modeling methodology have the advantage of being applicable to other systems provided the availability of a sufficient database
7
Shelley, James Adam. "Monitoring and Evaluating the Influences of Class V Injection Wells on Urban Karst Hydrology." TopSCHOLAR®, 2018. https://digitalcommons.wku.edu/theses/3086.
Анотація:
The response of a karst aquifer to storm events is often faster and more severe than that of a non-karst aquifer. This distinction is often problematic for planners and municipalities, because karst flooding does not typically occur along perennial water courses; thus, traditional flood management strategies are usually ineffective. The City of Bowling Green (CoBG), Kentucky is a representative example of an area plagued by karst flooding. The CoBG, is an urban karst area (UKA), that uses Class V Injection Wells to lessen the severity of flooding. The overall effectiveness, siting, and flooding impact of Injection Wells in UKA’s is lacking; their influence on groundwater is evident from decades of recurring problems in the form of flooding and groundwater contamination. This research examined Class V Injection Wells in the CoBG to determine how Injection Well siting, design, and performance influence urban karst hydrology. The study used high-resolution monitoring, as well as hydrologic modeling, to evaluate Injection Well and spring responses during storm and baseflow conditions. In evaluating the properties of the karst aquifer and the influences from the surrounding environment, a relationship was established between precipitation events, the drainage capacity of the Injection Wells, and the underlying karst system. Ultimately, the results from this research could be used to make sound data-driven policy recommendations and to inform stormwater management in UKAs.
8
Gomari, Daniel Parviz [Verfasser], Jan [Akademischer Betreuer] Krumsiek, Karsten [Gutachter] Suhre, and Jan [Gutachter] Krumsiek. "Novel network-based methods for multi-omics data analysis and interpretation / Daniel Parviz Gomari ; Gutachter: Karsten Suhre, Jan Krumsiek ; Betreuer: Jan Krumsiek." München : Universitätsbibliothek der TU München, 2021. http://d-nb.info/1235664775/34.
9
Stegmaier, Saskia [Verfasser], Thomas F. [Akademischer Betreuer] Fässler, Hubert [Akademischer Betreuer] Schmidbaur, and Karsten [Akademischer Betreuer] Reuter. "Clusters and Networks of Tetrel Elements and Late d Block Metals in Ternary Intermetallic Phases with Alkali and Alkaline Earth Metals / Saskia Stegmaier. Gutachter: Thomas F. Fässler ; Hubert Schmidbaur ; Karsten Reuter. Betreuer: Thomas F. Fässler." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1051935032/34.
10
Bailly, David. "Vers une modélisation des écoulements dans les massifs très fissurés de type karst : étude morphologique, hydraulique et changement d'échelle." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT027H/document.
Анотація:
Les aquifères fissurés de type karst contiennent d'importantes ressources en eau. Ces aquifères sont complexes et hétérogènes sur une gamme d'échelles importantes. Leur gestion nécessite l'utilisation d'outils et de méthodologies adaptés. Dans le cadre de cette étude, différents outils et méthodologies numériques d'étude ont été développés pour la modélisation des aquifères karstiques, et plus généralement, des milieux poreux très fissurés 2D et 3D - en mettant l'accent sur la morphologie et sur le comportement hydrodynamique du milieu à travers la notion de changement d'échelle ("second changement d'échelle", reposant sur un modèle d'écoulement local de type Darcy et/ou Poiseuille avec quelques généralisations). Plusieurs axes sont explorés concernant la morphologie du milieu poreux fissuré (milieux aléatoires, milieux booléens avec réseaux statistiques de fissures, mais aussi, modèles morphogénétiques). L'étude du changement d'échelle hydrodynamique tourne autour du concept de macro perméabilité. Dans un premier temps, l'étude porte sur un modèle de perte de charge linéaire darcien. Les perméabilités effectives sont calculées numériquement en termes des fractions volumiques de fissures et du contraste de perméabilité matrice/fissures. Elles sont analysées et comparées à des modèles théoriques (analytiques). Une étude particulière des effets de quasi-percolation pour les grands contrastes aboutit à la définition de trois fractions critiques liées à des seuils de percolation. Pour tenir compte des effets inertiels dans les fissures, l'étude est étendue au cas d'une loi locale comprenant un terme quadratique en vitesse (Darcy/Ward-Forchheimer). Une perméabilité macroscopique équivalente non linéaire est définie et analysée à l'aide d'un modèle inertiel généralisé (linéaire/puissance). Enfin, l'anisotropie hydraulique à grande échelle du milieu fissuré est étudiée, en termes de perméabilités directionnelles, à l'aide d'une méthode numérique d'immersionKarstic aquifers contain large subsurface water resources. These aquifers are complex and heterogeneous on a large range of scales. Their management requires appropriate numerical tools and approaches. Various tools and numerical methodologies have been developed to characterize andmodel the geometry and hydraulic properties of karstic aquifers, more generally, of highly fissured 2D and 3D porous media. In this study, we emphasize morphological characterization, and we analyze hydrodynamic behavior through the concept of upscaling ("second upscaling"). Concerning the morphology of fissured porous media, several axes are explored : random media, composite random Boolean media with statistical properties, and morphogenetic models. Hydrodynamic upscaling is developed using the macro-permeability concept. This upscaling method is based on either Darcy's linear law, or on a linear/quadratic combination of Darcy's and Ward-Forchheimer's quadratic law (inertial effects). First, the study focuses on Darcy's linear head loss law, and Darcian effective permeabilities are calculated numerically in terms of volume fractions of fissures and "fissure/matrix" permeability contrasts. The results are analysed and compared with analytical results and bounds. A special study of percolation and quasi-percolation effects, for high contrasts, leads to defined three critical fractions. These critical fractions are "connected" to percolation thresholds. Secondly, in order to consider inertial effect in fissures, the study is extended to a local law with a quadratic velocity term (Darcy/Ward-Forchheimer). Then, an equivalent nonlinear macroscopic permeability is defined and analysed using a generalized inertial model (linear/power). Finally, the large scale hydraulic anisotropy of fissured medium is studied, in terms of directional permeabilities, using an "immersion" numerical method
Книги з теми "Karstic networks":
1
Hank, Karsten, Frank Schulz-Nieswandt, Michael Wagner, and Susanne Zank, eds. Alternsforschung. Nomos Verlagsgesellschaft mbH & Co. KG, 2019. http://dx.doi.org/10.5771/9783845276687.
Анотація:
This handbook aims to provide an overview of knowledge about age and ageing in ‘Western’ societies at the beginning of the 21st century, which is intended to be equally suitable for research and practice. It focuses on relevant contributions from the social and behavioural sciences and their access to selected aspects of age and ageing. Its main topics can be described as quintessential core subjects, e.g. theories of ageing, socio-economic situation and inequalities, mental and physical health, social networks and social participation. These are supplemented by contributions on often marginalised topics and ‘emerging topics’ such as very old age, experiences of violence and delinquency, sexuality, and the spirituality and ethics of ageing. Finally, a series of topics relevant to everyday life and research practice (e.g. age and technology and data collection among the elderly) form a third central component of the book. With contributions by Heike Baranzke | Hermann Brandenburg | Susanne Brose | Josef Ehmer | Yvonne Eisenmann | Lea Ellwardt | Marcel Erlinghagen | Uwe Fachinger | Luise Geithner | Thomas Görgen | Bernadette Groebe | Helen Güther | Hans Gutzmann | Karsten Hank | Peter Häussermann | Rolf G. Heinze | Kira Hower | Anna Janhsen | Roman Kaspar | Daniela Klaus | Lars-Oliver Klotz | Franziska Kunz | Lisa Luft | Katharina Mahne | Michael Neise | Frank Oswald | Johannes Pantel | Susanne Penger | Holger Pfaff | M. Christina Polidori | Christian Rietz | Charlotte Şahin | Anna Schlomann | Holger Schmidt | Laura Schmidt | Wiebke Schmitz | Katrin Schneiders | Frank Schulz-Nieswandt | Andreas Simm | Julia Simonson | Anja Steinbach | Stephanie Stock | Julia Strupp | Clemens Tesch-Römer | Claudia Vogel | Raymond Voltz | Michael Wagner | Hans-Werner Wahl | Inka Wilhelm | Christiane Woopen | Susanne Zank
2
Lindner, Ralf, Michael Decker, Elisabeth Ehrensperger, Nils B. Heyen, Stephan Lingner, Constanze Scherz, and Mahshid Sotoudeh, eds. Gesellschaftliche Transformationen. Nomos Verlagsgesellschaft mbH & Co. KG, 2021. http://dx.doi.org/10.5771/9783748901556.
Анотація:
The intensively discussed term transformation refers to the comprehensive restructuring of processes and behaviour in order to address societal challenges posed by far-reaching changes in energy, transport, production and agricultural systems. Since such complex transformations are always accompanied by uncertainties about their effects and consequences, the contributions in this volume critically examine the opportunities and risks involved in these processes and discuss the possibilities and limits of technology assessment in the context of societal transformations. The volume brings together the academic contributions to the 8th international conference of the Technology Assessment Network, which took place in Karlsruhe from 7th to 8th November 2018. With contributions by Fabian Adelt, Marius Albiez, Annika Arnold, Walaa Bashary, Anja Bauer, Richard Beecroft, Alexander Bogner, Stefan Böschen, Tanja Bratan, Simone Colombo, Michael Decker, Rico Defila, Antonietta Di Giulio, Marion Dreyer, Elisabeth Ehrensperger, Philipp Ellett, Lorenz Erdmann, Ali Abdelshafy Ezzat, Erik Fisher, Michael Friedewald, Livia Fritz, Daniela Fuchs, Maryegli Fuss, Armin Grunwald, Niklas Gudowsky, Kristin Hagen, Simeon Hassemer, Alexandra Hausstein, Nils B. Heyen, Diego Iván Hidalgo Rodriguez, Peter Hocke, Florian Hoffmann, Sebastian Hoffmann, Michael Jonas, Dorothee Keppler, Jeanette Klink-Lehmann, Hannah Kosow, Cordula Kropp, Sophie Kuppler, Bastian Lange, Wolfgang Liebert, Ralf Lindner, Stephan Lingner, Andreas Lösch, Maria Maia, Martin Nicholas, Melanie Mbah, Franziska Meinherz, Rolf Meyer, Johanna Myrzik, Lisa Nabitz, Linda Nierling, Oliver Parodi, Witold-Roger Poganietz, Carmen Priefer, Filippo Reale, Ernst Dieter Rossmann, André Schaffrin, Dirk Scheer, Constanze Scherz, Jan Cornelius Schmidt, Maike Schmidt, Flurina Schneider, Andreas Seebacher, Astrid Segert, Mahshid Sotoudeh, Helge Torgersen, Ulrich Ufer, Karsten Weber, Matthias Weber and Johannes Weyer.
Частини книг з теми "Karstic networks":
1
Jaquet, O. "Stochastic Model of Karstic Conduit Networks Using Lattice Gas Simulations." In Geostatistics Wollongong’ 96, 1124–33. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5726-1_42.
2
Allam, Antoine, and Wajdi Najem. "Artificial Neural Networks Modeling of a Karstic Watershed in Mount Lebanon." In EuroKarst 2016, Neuchâtel, 203–14. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-45465-8_21.
3
Mance, Diana, Danijela Lenac, Maja Radišić, Davor Mance, and Josip Rubinić. "The use of 2H and 18O isotopes in the study of coastal karstic aquifers." In Ninth International Symposium “Monitoring of Mediterranean Coastal Areas: Problems and Measurement Techniques”, 525–34. Florence: Firenze University Press, 2022. http://dx.doi.org/10.36253/979-12-215-0030-1.48.
Анотація:
Complexity of karst groundwater networks requires implementation of standard hydrogeological monitoring and unconventional methods of investigation. We present the results of isotope composition analysis for three karst springs and rain water collected in their hinterland. During two years, spring water samples were collected on a weekly and rain samples on a monthly basis. The main findings are: winter precipitation of Mediterranean origin dominates springs' recharge, a dual porosity model is a fit for the studied systems, and hinterlands of the springs have different retention capabilities.
4
Kong A Siou, L., A. Johannet, S. Pistre, and V. Borrell. "Flash Floods Forecasting in a Karstic Basin Using Neural Networks: the Case of the Lez Basin (South of France)." In Advances in Research in Karst Media, 215–21. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-12486-0_33.
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Drobinina, Elena V., Tatyana G. Kovaleva, Denis R. Zolotarev, and Valerii N. Kataev. "The Geological Structure Style of Karst Massive in the Karst Susceptibility Assessment." In Lecture Notes in Networks and Systems, 205–17. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-89477-1_20.
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Rahmani, Sita, Takehiko Murayama, Shigeo Nishikizawa, and Muhammad Sani Roychansyah. "Local Governance of Sustainability Transition in Community-Scale Solar Water Pumping Systems in Indonesia." In Environment & Policy, 439–62. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-15904-6_23.
Анотація:
AbstractSustainability transition emerges in various types of community-scale projects. Indonesia has been actively implementing solar water pumping systems (SWPS) since 1982. However, for almost four decades, SWPS, as a niche innovation, have not achieved significant adoption of solar technology in the water utility sector. This study aimed to assess local governance aspects of SWPS in the context of sustainability transition from two perspectives: internal niche management and local actors. We assessed nine SWPS projects in Yogyakarta Province, Indonesia, using structured interviews that were analyzed using descriptive statistics and qualitative content analysis. The results showed that the discontinuation of support made SWPS unsustainable, operating only for an average of 4 years. Crucial operational factors included electrical damage, insufficient training, and lack of funds for damage repair. The iterative process of learning, network building, and vision did not eventuate. SWPS have direct benefit on the water supply; however, technological performance feedback related to the karst environment was insufficiently addressed and the network of actors did not expand to higher levels of local government. SWPS were viewed as an unreliable technology; hence, there was no vision for applying SWPS as a water utility. Solar photovoltaic pumps need strong support to compete with diesel and electrical water utility pumps. To achieve sustainability transition, it is imperative to generate vision, promote policy change, and build committed networks within local government rather than simply replicate the number of project installations.
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Savary, Michaël, Anne Johannet, Nicolas Massei, Jean Paul Dupont, and Emmanuel Hauchard. "Limits in Using Multiresolution Analysis to Forecast Turbidity by Neural Networks. Case Study on the Yport Basin, Normandie-France." In Advances in Karst Science, 129–35. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-14015-1_15.
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Kong-A-Siou, L., V. Borrell-Estupina, A. Johannet, and S. Pistre. "Neural Networks for Karst Spring Management. Case of the Lez Spring (Southern France)." In Hydrogeological and Environmental Investigations in Karst Systems, 361–69. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-17435-3_41.
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Auterives, Chrystelle, Stéphane Binet, and Patrick Albéric. "Inferred Conduit Network Geometry from Geological Evidences and Water-Head in a Fluvio-Karstic System (Val D’Orleans, France)." In H2Karst Research in Limestone Hydrogeology, 49–58. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06139-9_3.
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Trichakis, I. C., G. P. Karatzas, and I. K. Nikolos. "Quantification of artificial neural network uncertainty with bootstrap percentile intervals for the prediction of a karstic aquifer's response." In Environmental Hydraulics. Volume 2, 691–96. London: CRC Press, 2022. http://dx.doi.org/10.1201/9780429100314-12.
Тези доповідей конференцій з теми "Karstic networks":
1
Corbo, Diego Nicolas, Rodolphe Lathion, Federico Games, and Vincent Martinuzzi. "High Resolution Discrete Fracture Network Application for Polymer Flooding Design in a Naturally Fractured Carbonate." In Gas & Oil Technology Showcase and Conference. SPE, 2023. http://dx.doi.org/10.2118/214091-ms.
Анотація:
Abstract Despite their higher complexity (Juri et al., 2015) and usually more challenging commercial development, naturally fractured reservoirs account for a significant portion of oil and gas reserves worldwide (Sun et al., 2021). Typically, natural fractures tend to enhance the productivity of the wells, yet they also tend to accelerate reservoir depletion, often leading to sub-optimal field production and leaving significant volumes of hydrocarbons behind (Aguilera, 1995). In this work, we propose a specific polymer injection design that can provide the conditions for fracture-matrix counter-current flow to develop in a naturally fractured carbonate reservoir. In turn, this flow could trigger a virtuous cycle where the displacement front is progressively slowed down, increasing the efficiency of the displacement process and the oil recovery. This study focused on the integration of multiple sets of data to characterize karstic and tectonic fractures in a discrete fracture network (DFN) model and its posterior use in a dual medium simulation model to determine polymer flooding optimal spacing and injection strategy in a complex, naturally fractured carbonate system. An innovative and integrated approach combining 3D seismic data, bore-hole imagery (BHI), cores, and production data was applied to characterize and represent karstic features. The applied workflow consisted of (1) identification and manual picking of karstic features on BHI, (2) deterministic picking of karstic features as geobodies on the 3D seismic (enhanced similarity volume), (3) integrated implementation of the karstic features into the geological model using advanced geostatistical methods (Multi-Points Simulation, or MPS), and (4) implementation of resulting enhanced reservoir properties on a fit for purpose high-resolution dynamic model (dual porosity/dual permeability). Multiple simulations were run to evaluate different sensitivities including injection rates, injection strategy, completion approach, and producer-injector pattern spacing. Particularly for the latter, a robust karst/fracture system characterization was critical to propose optimal pattern sizes which aim to simultaneously avoid early polymer breakthrough -in shorter than optimal designs and minimize potential shear thickening degradation effects tied to higher polymer throughput required by excessive producer-injector distancing. In terms of the completion interval, the DFN-derived properties were also strongly conditioning the selection of the injection interval with noticeable effects and contrasting results. Because of the superposed features constituting the total fracture system and their different origins, a field-level comprehension of anisotropy and local intensity of the fractures is critical for selecting both the wells for the injectivity test and the potential area for the pilot in the next stage of the project.
2
Soni, A., J. Monsalve, and N. Ripepi. "Analysis of Pillar Strength and Design in a Karst-Affected Underground Stone Mine." In 56th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2022. http://dx.doi.org/10.56952/arma-2022-0924.
Анотація:
ABSTRACT: Underground stone mines are often prone to karst formations created by the gradual erosion of carbonate rocks due to groundwater flow. The prevalent fracture network in these stone deposits offers favorable conditions for acidic dissolution, which leads to the formation of large karst cavities. The interaction of these cavities with the extensive presence of discontinuities is the major cause of ground control problems encountered during stone mining operations. This paper presents a case study for analyzing the effect of the karst cavity on the strength of a pillar in an underground room-and-pillar stone mine. Numerical analyses show that the presence of these voids in a pillar contributes to a considerable decrease in load-bearing capacity. Any development through excavation or blasting into the affected areas may pose a safety hazard to the miners. Apart from that, this may also disrupt production and burden the pre-planned mine operations. The study for estimating pillar strength using numerical modeling could provide a pragmatic approach to designing future pillars affected by karsts. The shape and volume of the karst cavities inside the concerned pillar were approximated using ground-penetrating radar (GPR) surveys. LiDAR scans were performed to map the discontinuity network around the pillars, and Discrete Fracture Network (DFN) technique was implemented to simulate the joint network in the pillar’s rock mass. The behavior of the pillar with the increase in axial compressive stress was observed with the help of Distinct-element modeling (DEM) using 3DEC software. The pillar’s rock mass is simulated using Elastic and Mohr-Coulomb constitutive models. Two scenarios are presented to assess the pillar strength with and without the presence of karst. Pillar strength is compared to the estimated current stress levels to understand the potential for improvement in the pillar design. The research emphasizes the importance of pillar design while maximizing safety and production in underground stone mines with karst cavities to prevent pillar instability or local roof failures.
3
Olmeda, Mariana, and Erich Funk. "Proposing an Adaptable Subsurface Data Assessment Workflow for Identifying Fluid Pathways in Fractured Carbonate Reservoirs." In GOTECH. SPE, 2024. http://dx.doi.org/10.2118/219182-ms.
Анотація:
Abstract The understanding of reservoir fluid pathways and their dynamic behaviour through time is essential for a successful development of a fractured carbonate reservoir. This work aims to propose an adaptable data analysis workflow to optimize the characterization of the reservoir throughout its life cycle. Accounting for different maturity stages and geological scenarios, the proposed evaluation sequence supports an optimum assessment of the reservoir architecture and the understanding of its production behaviour and evolving performance. The methodology involves the dynamic evaluation and integration of geo-parameters, such as fault damage zones, fracture corridors and connected vuggy layers. The corresponding workflow enables a flexible data assessment of flow-dominating permeability zones and the degree of their spatial connectivity between wells and areas of undrained reservoir potential. The interpretation of image logs, regional field work and outcrops, seismic-scale faults, karstic sections, fractures and sub-seismic damage zones are combined to characterize flow zones and their corresponding hydraulic hierarchy expressed in the dynamic behaviour at well-scale. The results integrate all information extracted and interpreted from available data sets, determining the preferential networks for fluid movement and how these can be linked to current field development strategies and reservoir management initiatives. The utilized flexible workflow accommodates both parallel and sequential tasks and is adaptive to each given geological case, supporting a streamlined data analysis towards an optimized understanding of reservoir dynamics. The reservoir assessment based on this methodology allows to establish conceptual flow scenarios and their potential impact on field performance. This analysis does also help identifying favourable areas for well placement, including refinements of optimum well design, strategic packer placement and production mitigations aimed towards a stable and sustained field life. This paper is a contribution to the continuous learning process in field development optimization of heterogeneous fractured carbonate reservoirs. By implementing a flexible data analysis workflow, adaptive to complex geological and variable data scenarios, this work identifies the dynamic range of potential hydrocarbon and water pathways that will determine reservoir performance and helping to optimize the strategy for its development.
4
Earnest, E., T. Playton, S. Vitel, and R. Hui. "Discrete Fracture Network Modeling of a Giant, Naturally Fractured Carbonate Reservoir, Korolev Field, Kazakhstan." In 3rd International Discrete Fracture Network Engineering Conference. ARMA, 2022. http://dx.doi.org/10.56952/arma-dfne-22-0041.
Анотація:
Abstract This study details characterization and Discrete Fracture Network (DFN) modeling of a naturally fractured carbonate reservoir with natural fractures and karst, or “non-matrix,” that are essential to production. Characterization of non-matrix follows a workflow where non-matrix is interpreted from image logs and core. Prediction of non-matrix intensity trends away from well control is performed using regression to identify covariance with static grid properties and modeled using Sequential Gaussian Simulation (SGS). DFNs are built to model fractures and karst with defined statistical distributions of orientation, size, aperture, and permeability. Several DFN realizations are created to capture uncertainty. A hybrid Embedded Discrete Fracture Model plus Dual Porosity Dual Permeability (DPDK) approach is employed for simulation. Each DFN is split into 3 different size bins, including “small” fractures upscaled and added to matrix; “medium” fractures upscaled and assigned to the DPDK grid; and “large” fractures and karst that are modeled as EDFM. The resulting EDFM+DPDK models are used in practice for forecasting and signposting primary production and IOR outcomes. This work highlights a workflow to incorporate fracture characterization with fracture prediction to build DFNs that are geologically robust, consistent with dynamic well test data, and application to EDFM+DPDK models for forecasting.
5
Fernandez-Ibanez, Fermin, Paul J. Moore, and Gareth D. Jones. "Quantitative Assessment of Karst Pore Volume in Carbonate Reservoirs Using Discrete Karst Networks." In 2019 AAPG Annual Convention and Exhibition. Tulsa, OK, USA: American Association of Petroleum Geologists, 2019. http://dx.doi.org/10.1306/42424fernandez-ibanez.
6
Zongjun, Gao, Ren Jiaguo, Cui Haohao, and Li Zhenxing. "The analysis of hydrochemical cause of karst." In 2011 International Conference on Consumer Electronics, Communications and Networks (CECNet). IEEE, 2011. http://dx.doi.org/10.1109/cecnet.2011.5769332.
7
Azwar, Olivia, Dian Permanasari, Nadia Ardikani, Nabilah Adani, Didit Kusuma, Budi Abrar, Taufik Nordin, et al. "Integration of High-Definition Karst Mapping and Quantitative Porosity Analysis from Borehole Image to Improve Well Placement in Complex Carbonate Reservoir of East Java Basin." In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211708-ms.
Анотація:
Abstract The CD Carbonate in X-Field, East Java Basin has multiple reservoir targets with varying flow units, predominantly because of secondary porosity development from karst processes. Each of these reservoirs are relatively thin and the continuity of the karst within the reservoir is random. The amount of producible hydrocarbon will rest on the length of the drain section along the reservoir and the amount of karst intersected by the trajectory. Thus, maintaining the trajectory inside the carbonate reservoir while targeting the karst position is important for productivity. To maintain the production in the field, a new platform was built to the southeast of the first platform, aiming for a new development area. Five horizontal wells were planned as part of the second development phase. The first horizontal well is the most challenging one because of the high uncertainty of the structural dips along the lateral length triggered by the low seismic resolution and the limited nearby offset wells for control points. Moreover, the offset wells show inconsistent log properties that complicate the correlation to land into the targeted karst level within the reservoir. Initially, a pilot hole was planned to reduce the landing uncertainties; however, it was being challenged for cost efficiency. Therefore, a well placement strategy was proposed instead, including landing and geosteering using a new logging-while-drilling (LWD) combination of advanced high-definition reservoir mapping technology, high-resolution laterolog borehole imaging technology, and a multifunction LWD tool. In this paper we demonstrate the complete preparation of the well placement project, strategy, and evaluation using this new LWD combination for better interpretation of the reservoir. The deeper reading and higher resolution of the new reservoir mapping technology have permitted continuous mapping of the target reservoir, which typically has 35- to 50-ft thickness, to reduce the structural uncertainties from seismic. For the first time, it successfully revealed the karst network within the reservoir with greater details, identified by a blue-vein color spectrum of the resistivity inversion caused by seawater invasion or clay-filled karst. This high-definition karst mapping has helped to land the well precisely at the target karst sweet spot, improving the understanding of the karst characters along the trajectory, and providing higher confidence in the real-time geosteering decision. The high-resolution borehole image revealed the carbonate rock texture and karst/vugs appearance on a smaller scale, which was used to analyze the secondary porosity distribution and contribution along the trajectory using a quantitative image-based porosity analysis method. By integrating the high-definition reservoir mapping inversion interpretation and porosity analysis from a high-resolution borehole image, we were able to bridge the gap from seismic to reservoir scale, and finally to link the karst scale down to the vug pore sizes, for a better geological understanding and an improved geosteering strategy in the field.
8
Chen, Xi, Cai Chen, Qinqin Hao, Zhicai Zhang, and Peng Shi. "Simulation of Rainfall-Underground Outflow Responses of a Karstic Watershed in Southwest China with an Artificial Neural Network." In 11th Multidisciplinary Conference on Sinkholes and the Engineering and Environmental Impacts of Karst. Reston, VA: American Society of Civil Engineers, 2008. http://dx.doi.org/10.1061/41003(327)41.
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Grenier Ferreira Motta, Gabriel, Monique Feitosa Dali, Sergio Ribeiro, and Marcio CARVALHO. "Permeability prediction of karst porous media using Convolutional Neural Networks." In 19th Brazilian Congress of Thermal Sciences and Engineering. ABCM, 2022. http://dx.doi.org/10.26678/abcm.encit2022.cit22-0229.
10
Kim, Yong Je, Boo Hyun Nam, and Qipeng Zheng. "An artificial neural network approach to sinkhole hazard assessment for East Central Florida." In National Cave and Karst Research Institute Symposium 8. National Cave and Karst Research Institute, 2020. http://dx.doi.org/10.5038/9781733375313.1031.