References of "Schroeder, Christian"
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See detailEvaluation of instability hazards in rock masses influenced by mining works in the coal basin of Liege.
Schroeder, Christian ULg; Flamion, B.; Berger, J.-L. et al

in Post-Mining 2008 (2008, February)

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See detail3D fully coupled multiphase modelling of Ekofisk reservoir
Ringlet, Clémence; Charlier, Robert ULg; Schroeder, Christian ULg et al

in Shao, Jian-Fu; Burlion, Nicolas (Eds.) Thermo-hydromechanical and chemical Coupling in Geomaterials and Applications (2008)

During reservoir production, the depletion usually induces a compaction of the reservoir layers. To enhance oil recovery, waterflooding operations are generally performed but, in the North Sea chalk ... [more ▼]

During reservoir production, the depletion usually induces a compaction of the reservoir layers. To enhance oil recovery, waterflooding operations are generally performed but, in the North Sea chalk reservoir, they have also induced an additional compaction. This latter phenomenon has a positive impact (improve the ‘Compaction drive’ oil recovery) but endangers the offshore platforms and causes huge extra costs. The coupling effects between mechanical behaviour and fluids flow are thus a key issue in petroleum engineering. Pasachalk program I & II have proposed a constitutive model (referred as Pasachalk model), where the suction is the key parameter to explain the water weakening effect. This model has been used for the modelling of waterflooding experiment on chalk plug and bi-dimensional reservoir. However, as the reservoir modelling is actually a 3D model, the purpose of this paper is to present 3D fully coupled modelling of a simplified Ekofisk reservoir during production and waterflooding phases. In order to exhibit the influence of the constitutive mechanical model, different studies are performed: increasing the complexity of the mechanical model (from an elastic model up to the Pasachalk one with suction effect). The numerical results show the influence of the mechanical law on the oil production and exhibit that only an elasto-plastic law with suction effects succeeds to reproduce compactions during both production and waterflooding. [less ▲]

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See detailA general approach to assess hydro-mechanical changes of natural clay barriers due to physico-chemical interactions with radwaste in deep disposal sites
Schmitz, Robrecht M; Schroeder, Christian ULg; Charlier, Robert ULg

in Physics & Chemistry of the Earth - Parts A/B/C (2007), 32(8-14), 922-928

Radwaste must be isolated from the biosphere for a long periods. To isolate waste, engineered clay barriers can be constructed. The functional life of such engineered barriers must be much longer (factor ... [more ▼]

Radwaste must be isolated from the biosphere for a long periods. To isolate waste, engineered clay barriers can be constructed. The functional life of such engineered barriers must be much longer (factor 100-1000) than that of more common engineered structures. Can the responsible engineer guarantee a functional life of several thousand years? Probably not, therefore waste like radwaste is stored at great depths, in a combination of geological and engineered barriers. During the storage period the waste itself (radiation) or derived products (oxidation of containers) can interact with the engineered and geological clay barriers. In,this contribution it is discussed how such interactions affect the hydro-mechanical properties of clay barriers. First some examples are given that show how properties of clays change at surface conditions if clays are exposed to typical waste products like different cations. Thereafter a method is proposed to classify the potential of hydro-mechanical modifications at three different scales: the particle level, the interlayer level and the tetrahedral-octahedral level. Next it is explained why the reactivity of clays at depth during long-term waste isolation is different (smaller) from the better known reactivity of clays at the surface. Instead of directing too much attention to such well known interactions, the focus for a safe deep disposal of radwaste should be directed to reactions that play a role at depth if, e.g. damage due to radiation occurs. Only if such reactions can be excluded, a safe storage of waste is possible. (C) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailA deterministic/stochastic model to predict the variation in bulk modulus of chalk
Collin, Frédéric ULg; Schroeder, Christian ULg; De Gennaro, Vincenzo et al

in Geotechnique (2005), 55(2), 135-141

Ekofisk, located 200 km west of the Norwegian coast, is one of the main oilfields in the North Sea. Since the early 1980s severe compaction of chalk reservoir layers has been observed as a consequence of ... [more ▼]

Ekofisk, located 200 km west of the Norwegian coast, is one of the main oilfields in the North Sea. Since the early 1980s severe compaction of chalk reservoir layers has been observed as a consequence of reservoir depletion during oil production. Subsequently, this compaction has been amplified by assisted oil recovery using seawater flooding. The development of our understanding of the inherent mechanisms of this phenomenon has been the objective of extensive experimental investigations in the last two decades. Owing to the very high cost of cored material from the reservoir, experiments are usually performed on chalk samples from an outcrop in Belgium lying at the same stratigraphic level as the Ekofisk reservoir chalks. However, even at the laboratory sample scale,. experimental variability of material response is observed. From a theoretical and numerical point of view, the determination of the mechanical properties of the material is of utmost importance for accurate modelling at both sample scale (laboratory tests) and reservoir scale. The aim of this paper is to introduce a stochastic approach within a deterministic constitutive model of chalk to enable the influence of material heterogeneity to be included in analyses for the range of observed mechanical responses. In modelling the random distribution of material parameters, the time-consuming Monte Carlo simulation method is replaced by a more efficient stochastic modelling technique. The results are given in the form of statistical parameters for the experimental laboratory test responses. The parameters of the distribution law (mean value, range of variation, spatial correlation structure) are fitted to reproduce the range of experimental responses observed at sample scale. Interest is focused on the variability of the chalk bulk modulus, as observed during isotropic compression tests. The proposed methodology provides a satisfactory explanation for the variability of response observed at the sample scale. The potential for extending the proposed approach to reservoir scale is briefly discussed. [less ▲]

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See detailChemo-mechanical interactions in clay: a correlation between clay mineralogy and Atterberg limits
Schmitz, R. M.; Schroeder, Christian ULg; Charlier, Robert ULg

in Applied Clay Science (2004), 26(1-4), 351-358

Among some few others tests, the evaluation of the Atterberg limits is a very basic soil mechanical test allowing a first insight into the chemical reactivity of clays. Basically, the liquid limit and the ... [more ▼]

Among some few others tests, the evaluation of the Atterberg limits is a very basic soil mechanical test allowing a first insight into the chemical reactivity of clays. Basically, the liquid limit and the plasticity index are highly and mainly influenced by the ability of clay minerals to interact with liquids. In this contribution, a correlation between the Atterberg limits and clay mineralogy is proposed. This correlation increases the understanding between clay mineralogists and engineers in soil mechanics; additionally a wealth of information in clay mineralogy literature is now available to predict the mechanical behaviour of clays via index tests. (C) 2003 Elsevier B.V. All rights reserved. [less ▲]

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See detailUsing the Complete Nano Engineering Geological Spectrum to Assess the Performance of Clay Barriers
Schmitz, Robrecht; Schroeder, Christian ULg; Thorez, Jacques ULg et al

in Hack, Robert; Azzam, Rafig; Charlier, Robert (Eds.) Engineering Geology for Infrastructure Planning in Europe (2004)

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See detailMechanical behaviour of chalk reservoir: Numerical modelling of water sensitivity and time dependence effects
Collin, Frédéric ULg; Cui, Yu Jun; Schroeder, Christian ULg et al

Conference (2003)

The paper proposes two numerical models ot the mechanical behaviour of chalk. First, an elasto-plastic constitutive law reproduces the different plastic mechanisms of the chalk and the influence of pore ... [more ▼]

The paper proposes two numerical models ot the mechanical behaviour of chalk. First, an elasto-plastic constitutive law reproduces the different plastic mechanisms of the chalk and the influence of pore fluids by introducing the concept of suction. Secondly, a model able to reproduce time dependence behaviour. Eventually, the paper gives a simulation of an academic reservoir during depletion and waterflooding phase. [less ▲]

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See detailMechanical behaviour of chalk reservoirs: numerical modelling of water sensitivity effects
Collin, Frédéric ULg; Cui, Yu Jun; Schroeder, Christian ULg et al

Conference (2003)

Chalk is the constituent material of numerous oil reservoirs in North Sea. The mechanical behaviour of a saturated chalk has been largely studied. However, different aspects of its behaviour are not yet ... [more ▼]

Chalk is the constituent material of numerous oil reservoirs in North Sea. The mechanical behaviour of a saturated chalk has been largely studied. However, different aspects of its behaviour are not yet well understood: material characteristics depend on the saturating fluids and chalk response is time-dependent. This paper proposes the PASACHALK numerical model: an elasto-plastic constitutive law is presented, which reproduces the different plastic mechanisms of the chalk (pore collapse and shear failure) and the influence of pore fluids. The water sensitivity of this soft rock is explained by the existence of suction effects in chalk. Finally, a simulation of a hypothetical reservoir is proposed to show the response of the elasto-plastic model during depletion phase and water injection phase. [less ▲]

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See detailTime-dependent behaviour of oil reservoir chalk: A multiphase approach
De Gennaro, Vincenzo; Delage, Pierre; Cui, Yu Jun et al

in Soils and Foundations (2003), 43(4),

In the North Sea Ekofisk oilfield, oil is located in a 300 m thick layer of porous chalk (n = 40-50%) at a 3000 m depth. After the initial phase of depletion an enhanced oil recovery procedure was carried ... [more ▼]

In the North Sea Ekofisk oilfield, oil is located in a 300 m thick layer of porous chalk (n = 40-50%) at a 3000 m depth. After the initial phase of depletion an enhanced oil recovery procedure was carried out by injecting sea water (waterflooding). An unexpected consequence of this waterflooding has been the occurrence of a seafloor subsidence, corresponding up to now to a decrease of the seafloor level of approximately 10 m. It is now well recognised that hydro-mechanical coupling involving multiphase fluid interactions (oil and water) is determinant for the interpretation of the phenomenological aspects associated with the chalk compaction and the related subsidence observed in the North Sea oilfields (Ekofisk reservoir) when water flooded. The subsidence due to waterflooding is interpreted as a collapse phenomenon due to suction decrease, typical of loose and low plasticity unsaturated soils when wetted under load. On the other hand, time-dependent stress-strain behaviour of geomaterials is one of the major concerns in soil mechanics and, in effect, subsidence includes creep effects. A multiphase approach, including creep effects under controlled suction levels, is proposed in this paper; the preliminary results of this study are presented and discussed. Attention will be focused at first on the theoretical approach, supplying the essential elements for the work, and on the interpretation of the experimental results. This will provide secondly the base for formulation and validation of the constitutive law proposed for the description of the time-dependent mechanical behaviour of the chalk. [less ▲]

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See detailConstitutive modeling of chalk. Application to waterflooding
Charlier, Robert ULg; Collin, Frédéric ULg; Schroeder, Christian ULg et al

in Auriault, J. L.; Geindreau, C.; Royer, P. (Eds.) Poromechanics II (2002)

Subsidence of chalk oil reservoirs in North Sea is related to the chalk compaction induced by fluid depletion and by the water – chalk interaction. A constitutive model is developed in order to take into ... [more ▼]

Subsidence of chalk oil reservoirs in North Sea is related to the chalk compaction induced by fluid depletion and by the water – chalk interaction. A constitutive model is developed in order to take into account these two effects. It is based on frictional – cap elastoplasticity and on the Barcelona unsaturated soil model. Oil – water – chalk interaction is modeled through the suction variable. In a second step, viscous effects are added to the model. After implementation into a finite element code, these tools allow to simulate a waterflooding experiment on a chalk sample. The model appears to reproduce qualitatively and quantitatively the experimental results. [less ▲]

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See detailA constitutive model for North Sea Chalk. Application to reservoir compaction and to waterflooding
Charlier, Robert ULg; Collin, Frédéric ULg; Schroeder, Christian ULg et al

in Pande, G. N.; Pietruszczak, S. (Eds.) Nomerical models in Geomechanics (2002)

Subsidence of chalk oil reservoirs in North Sea is related to the chalk compaction induced by fluid depletion and by the water – chalk interaction. A constitutive model is developed in order to take into ... [more ▼]

Subsidence of chalk oil reservoirs in North Sea is related to the chalk compaction induced by fluid depletion and by the water – chalk interaction. A constitutive model is developed in order to take into account these two effects. It is based on frictional – cap elastoplasticity and on the Barcelona unsaturated soil model. Oil – water – chalk interaction is modeled through the suction variable. The two saturating fluids flow is also developed. After implementation into a finite element code, these tools allow to simulate a waterflooding experiment on a chalk sample. The model appears to reproduce qualitatively and quantitatively the experimental results. [less ▲]

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See detailMechanical behaviour of Lixhe chalk partly saturated by oil and water: experiment and modelling
Collin, Frédéric ULg; Cui, Yu Jun; Schroeder, Christian ULg et al

in International Journal for Numerical and Analytical Methods in Geomechanics (2002), 26(9), 897-924

Two or more different fluids generally saturate chalk in oil reservoir, and therefore its behaviour can be very complicated. In this paper, a constitutive law is proposed for modelling the mechanical ... [more ▼]

Two or more different fluids generally saturate chalk in oil reservoir, and therefore its behaviour can be very complicated. In this paper, a constitutive law is proposed for modelling the mechanical behaviour of a chalk saturated by two non-miscible fluids, water and oil. The effects of the capillary pressure or suction are taken into account. They are considered as an independent variable, as in the Barcelona's basic model developed for unsaturated soils. On the other hand, internal friction and pore collapse are modelled as independent mechanisms. The determination of the parameters is based on triaxial and oedometer tests. Finally, in order to validate the model, predictions are compared with experimental results of water-flooding test. Copyright (C) 2002 John Wiley Sons, Ltd. [less ▲]

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See detailThe suitability of some Belgian Tertiary clays as construction material for landfill seals: Interaction with domestic landfill leachates
Schmitz, Robrecht; Ourth, Anne-Sophie; Dosquet, Danielle et al

in Aardkundige Mededelingen (2002), 12

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See detailOil field subsidence phenomena
Charlier, Robert ULg; Schroeder, Christian ULg; Radu, Jean-Pol ULg et al

in Revue Française de Génie Civil (2001), 5(6), 857-866

Subsidence of an chalky oil field is described. The mechanical behaviour of the chalk partly saturated by oil and water is described and allows to model the compaction occurring within a simple reservoir ... [more ▼]

Subsidence of an chalky oil field is described. The mechanical behaviour of the chalk partly saturated by oil and water is described and allows to model the compaction occurring within a simple reservoir model during the depletion as well as during the water injection. [less ▲]

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See detailGeomechanical constitutive modelling of a chalk partly saturated by oil and water
Collin, Frédéric ULg; Delage, Pierre; Schroeder, Christian ULg et al

in DGGT (Ed.) Eurock 2000 Symposium (2000)

Chalk in oil reservoir is generally saturated by two or more different fluids. In this paper, a constitutive law is proposed for the modelling of the mechanical behaviour of a chalk. The effects of the ... [more ▼]

Chalk in oil reservoir is generally saturated by two or more different fluids. In this paper, a constitutive law is proposed for the modelling of the mechanical behaviour of a chalk. The effects of the capillary pressure are taken into account. They are considered as an independent variable, as in the Barcelona’s basic model developed for unsaturated clay. On the other hand, internal friction and pore collapse are modelled as independent mechanisms. Eventually, the model predictions are compared with experimental results. [less ▲]

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See detailManuel relatif aux matières naturelles pour barrières argileuses ouvragées pour C.E.T. (centres d'enfouissement technique) et réhabilitation de dépotoirs en région wallonne.
Marcoen, Jean Marie ULg; Tessier, D.; Thorez, Jacques ULg et al

Report (2000)

La Région wallonne a confié aux laboratoires ci-dessus, la mission de rédiger un manuel technique qui décrit la sélection et la qualification des gisements et des matériaux argileux ainsi que le contrôle ... [more ▼]

La Région wallonne a confié aux laboratoires ci-dessus, la mission de rédiger un manuel technique qui décrit la sélection et la qualification des gisements et des matériaux argileux ainsi que le contrôle de la mise en œuvre des barrières argileuses ouvragées destinées à la réalisation des centres d'enfouissement technique (CET) ou à la réhabilitation de dépotoirs en Région wallonne. CET : Centre d’enfouissement technique, appellation pour les décharges, définies comme installations d’élimination contrôlée où des déchets sont définitivement entreposés sur ou dans le sol. La directive européenne a gardé l’appellation " décharge ". Ce manuel précise les moyens de qualification, de mise en œuvre et de contrôle de barrières étanches rapportées en fond de fouille, sur les flancs, ainsi qu'en couverture sur un site dont le substratum naturel ne satisfait pas aux contraintes environnementales réglementaires. Le matériau doit répondre à différents objectifs, liés à l'obtention d'un coefficient de perméabilité inférieur à 1.10-9m/s in situ, à la stabilité mécanique de l'ouvrage mais aussi au maintien des performances à long terme de la barrière argileuse dans les conditions d'exploitation. Cfr. annexe I de la DIRECTIVE 199/31/CE DU CONSEIL, du 28 avril 1999 En fonction de leurs propriétés, l'utilisation d'argiles (la définition précise du terme argile est donnée dans le manuel) s'impose. Néanmoins, une gamme plus large de matériaux naturels pourrait correspondre aux critères requis. Ainsi, en ce qui concerne la valorisation de sous produits des industries minérales, des boues ou des stériles miniers, la même démarche que celle préconisée pour les matériaux argileux naturels permettra de vérifier s'ils peuvent répondre aux exigences de qualification. Il convient en premier lieu d'apporter la preuve, via un laboratoire agréé, que le matériau ne présente pas de contamination qui le rende impropre à l'usage envisagé. Le manuel est réalisé sur base de l’expérience des auteurs et intègre celle de bureaux de contrôle agréés. Il prend aussi en compte les informations d’études réalisées à l’étranger. La démarche adoptée est de distinguer les différentes étapes de réalisation de la barrière argileuse : choix du matériau (gisement, qualité), définition des méthodes et moyens de mise en œuvre et contrôle in situ (planche d’essai), contrôle des fournitures sur chantier, contrôle final de la barrière étanche. [less ▲]

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See detailCalcul non linéaire des tassements induits par pompage dans des formations sédimentaires meubles
Dassargues, Alain ULg; Schroeder, Christian ULg

in Actes du Colloque National du CBGI/BCIG :’La Géologie de l’Ingénieur et l’eau dans le sous-sol’ (1997)

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