Development of a refinement criterion for adaptive mesh refinement in steam-assisted gravity drainage simulation     

Magnolia Mamaghani  Guillaume Enchéry  Claire Chainais-Hillairet 《Computational Geosciences》2011,15(1):17-34

Steam-assisted gravity drainage (SAGD) is an enhanced oil recovery process for heavy oils and bitumens. Numerical simulations of this thermal process allow us to estimate the retrievable volume of oil and to evaluate the benefits of the project. As there exists a thin flow interface (compared to the reservoir dimensions), SAGD simulations are sensitive to the grid size. Thus, to obtain precise forecasts of oil production, very small-sized cells have to be used, which leads to prohibitive CPU times. To reduce these computation times, one can use an adaptive mesh refinement technique, which will only refine the grid in the interface area and use coarser cells outside. To this end, in this work, we introduce new refinement criteria, which are based on the work achieved in Kröner and Ohlberger (Math Comput 69(229):25–39, 2000) on a posteriori error estimators for finite volume schemes for hyperbolic equations. Through numerical experiments, we show that they enable us to decrease in a significant way the number of cells (and then CPU times) while maintaining a good accuracy in the results.  相似文献   

Physical modelling of tsunami using a new pneumatic wave generator     

Tiziana Rossetto  William Allsop  Ingrid Charvet  David I. Robinson 《Coastal Engineering》2011

The physical simulation of tsunami in the laboratory has taken a major leap forward with the construction and testing of a new wave generator, capable of recreating scaled tsunami waves. Numerical tools fail to reproduce tsunami nearshore and onshore processes well, and physical experiments in large scale hydraulic facilities worldwide have been limited to the generation of solitary waves as an (controversial) approximation for evolved forms of tsunami. The new concept in wave generation presented herein is born of collaboration between UCL's Earthquake and People Interaction Centre (EPICentre) and HR Wallingford. It allows for the first time the stable simulation of extremely long waves led either by a crest or a trough (depressed wave). This paper presents the working concepts behind the new wave generator and the first stages of testing for verifying its capacities and limitations. It is shown that the new wave generator can not only reproduce solitary waves and N-waves with large wavelengths, but also the 2004 Indian Ocean Tsunami as recorded off the coast of Thailand (“Mercator” trace).  相似文献   

The restricted problem: An extension of Breakwell-Perko's matching theory     

Pierre Guillaume 《Celestial Mechanics and Dynamical Astronomy》1975,11(4):449-467

This paper extends Breakwell and Perko's ‘first order’ matching theory (1965, 1966) to a more general matching theory which is applicable to a wider class of second species solutions. In a first stage, the matching theory is elaborated on the basis of new assumptions on the orders of magnitude of the small parameters. In a second stage, we construct a matching theory which takes into account general assumptions which include our assumptions and Breakwell-Perko's.  相似文献   

Multi-method investigation of mass transfer mechanisms in a retrogressive clayey landslide (Harmalière,French Alps)     

Fiolleau  Sylvain  Jongmans  Denis  Bièvre  Gregory  Chambon  Guillaume  Lacroix  Pascal  Helmstetter  Agnès  Wathelet  Marc  Demierre  Michel 《Landslides》2021,18(6):1981-2000

Landslides - The mass transfer mechanisms in landslides are complex to monitor because of their suddenness and spatial coverage. The active clayey Harmalière landslide, located 30 km south of...  相似文献   

Curvature Attribute from Surface-Restoration as Predictor Variable in Kupferschiefer Copper Potentials     

Pablo Mejía-Herrera  Jean-Jacques Royer  Guillaume Caumon  Alain Cheilletz 《Natural Resources Research》2015,24(3):275-290

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Assessment of tsunami hazards in ports and their impact on marine vessels derived from tsunami models and the observed damage data   总被引：1，自引：0，他引：1  

Abdul Muhari  Ingrid Charvet  Futami Tsuyoshi  Anawat Suppasri  Fumihiko Imamura 《Natural Hazards》2015,78(2):1309-1328

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Long-term increase in diffuse groundwater recharge following expansion of rainfed cultivation in the Sahel,West Africa   总被引：1，自引：0，他引：1  

Maïmouna Ibrahim  Guillaume Favreau  Bridget R. Scanlon  Jean Luc Seidel  Mathieu Le Coz  Jérôme Demarty  Bernard Cappelaere 《Hydrogeology Journal》2014,22(6):1293-1305

Rapid population growth in sub-Saharan West Africa and related cropland expansion were shown in some places to have increased focused recharge through ponds, raising the water table. To estimate changes in diffuse recharge, the water content and matric potential were monitored during 2009 and 2010, and modeling was performed using the Hydrus-1D code for two field sites in southwest Niger: (1) fallow land and (2) rainfed millet cropland. Monitoring results of the upper 10 m showed increased water content and matric potential to greater depth under rainfed cropland (>2.5 m) than under fallow land (≤1.0 m). Model simulations indicate that conversion from fallow land to rainfed cropland (1) increases vadose-zone water storage and (2) should increase drainage flux (～25 mm year^?1) at 10-m depth after a 30–60 year lag. Therefore, observed regional increases in groundwater storage may increasingly result from diffuse recharge, which could compensate, at least in part, groundwater withdrawal due to observed expansion in irrigated surfaces; and hence, contribute to mitigate food crises in the Sahel.  相似文献   

Conditioning of Multiple-Point Statistics Facies Simulations to Tomographic Images   总被引：2，自引：2，他引：0  

Tobias Lochbühler  Guillaume Pirot  Julien Straubhaar  Niklas Linde 《Mathematical Geosciences》2014,46(5):625-645

Geophysical tomography captures the spatial distribution of the underlying geophysical property at a relatively high resolution, but the tomographic images tend to be blurred representations of reality and generally fail to reproduce sharp interfaces. Such models may cause significant bias when taken as a basis for predictive flow and transport modeling and are unsuitable for uncertainty assessment. We present a methodology in which tomograms are used to condition multiple-point statistics (MPS) simulations. A large set of geologically reasonable facies realizations and their corresponding synthetically calculated cross-hole radar tomograms are used as a training image. The training image is scanned with a direct sampling algorithm for patterns in the conditioning tomogram, while accounting for the spatially varying resolution of the tomograms. In a post-processing step, only those conditional simulations that predicted the radar traveltimes within the expected data error levels are accepted. The methodology is demonstrated on a two-facies example featuring channels and an aquifer analog of alluvial sedimentary structures with five facies. For both cases, MPS simulations exhibit the sharp interfaces and the geological patterns found in the training image. Compared to unconditioned MPS simulations, the uncertainty in transport predictions is markedly decreased for simulations conditioned to tomograms. As an improvement to other approaches relying on classical smoothness-constrained geophysical tomography, the proposed method allows for: (1) reproduction of sharp interfaces, (2) incorporation of realistic geological constraints and (3) generation of multiple realizations that enables uncertainty assessment.  相似文献   

Building damage from the 2011 Great East Japan tsunami: quantitative assessment of influential factors     

Natt Leelawat  Anawat Suppasri  Ingrid Charvet  Fumihiko Imamura 《Natural Hazards》2014,73(2):449-471

Based on the classification provided by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), the damage level of buildings impacted by the 2011 Great East Japan tsunami can be separated into six levels (from minor damage to washed away). The objective of this paper is to identify the significant predictor variables and the direction of their potential relationship to the damage level in order to create a predicting formula for damage level. This study used the detailed data of damaged buildings in Ishinomaki city, Miyagi prefecture, Japan, collected by MLIT. The explanatory variables tested included the inundation depth, number of floors, structural material, and function of the building. Ordinal regression was applied to model the relationship between the ordinal outcome variable (damage level) and the predictors. The findings indicated that inundation depth, structural material, and function of building were significantly associated with the damage level. In addition to this new type of model, this research provides a valuable insight into the relative influence of different factors on building damage and suggestions that may help to revise the classification of current standards. This study can contribute to academic tsunami research by assessing the contribution of different variables to the observed damage using new approaches based on statistical analysis and regression. Moreover, practical applications of these results include understanding of the predominant factors driving tsunami damage to structures, implementation of the relevant variables into the proposed, or alternative model in order to improve current damage predictions by taking into account not only inundation depth, but also variables such as structural material and function of building.  相似文献   

Contribution of {\text{P}}_{{{\text{CO}}_{ 2} {\text{eq}}}} and 13CTDIC Evaluation to the Identification of CO2 Sources in Volcanic Groundwater Systems: Influence of Hydrometeorological Conditions and Lava Flow Morphologies—Application to the Argnat Basin (Chaîne des Puys, Massif Central, France)     

Guillaume Bertrand  Hélène Celle-Jeanton  Sébastien Loock  Frédéric Huneau  Véronique Lavastre 《Aquatic Geochemistry》2013,19(2):147-171

Mineralization of groundwater in volcanic aquifers is partly acquired through silicates weathering. This alteration depends on the dissolution of atmospheric, biogenic, or mantellic gaseous CO₂ whose contributions may depend on substratum geology, surface features, and lava flow hydrological functionings. Investigations of $ {\text{P}}_{{{\text{CO}}_{ 2} {\text{eq}}}} $ and δ¹³C_TDIC (total dissolved inorganic carbon) on various spatiotemporal scales in the unsaturated and saturated zones of volcanic flows of the Argnat basin (French Massif Central) have been carried out to identify the carbon sources in the system. Mantellic sources are related to faults promoting CO₂ uplift from the mantle to the saturated zone. The contribution of this source is counterbalanced by infiltration of water through the unsaturated zone, accompanied by dissolution of soil CO₂ or even atmospheric CO₂ during cold periods. Monitoring and modeling of δ¹³C_TDIC in the unsaturated zone shows that both $ {\text{P}}_{{{\text{CO}}_{ 2} {\text{eq}}}} $ and δ¹³C_TDIC are controlled by air temperature which influences soil respiration and soil-atmosphere CO₂ exchanges. The internal geometry of volcanic lava flows controls water patterns from the unsaturated zone to saturated zone and thus may explain δ¹³C heterogeneity in the saturated zone at the basin scale.  相似文献