Notice bibliographique
Résumé
Abstract Tortuosity factor exerts a major influence in fluid flow in porous medium. However, this factor is very difficult to quantify from experimental measurements particularly in deformable medium. It is commonly treated as an empirical or curve-fitting parameter in determination of permeability. This study attempts to use electrical resistivity measurement method as an analytical tool to study how changes in grain fabric affect changes in tortuosity. The first phase of the study concentrates on development of a framework on the flow tortuosity behaviour observed in idealized granular assemblies of regular packings with uniform spheres subjected to various types of grain fabric alteration, such as matrix dilation and grain rearrangement (rolling and overriding). Then, the framework is extended to interpret data measured in real random systems of intact and sheared oil sand specimens. It was found that the locked structure in intact oil sand specimens produce relatively high tortuosity factors as compared to those in the idealized packings. Shear deformation disrupts this intrinsic structure reducing the tortuosity factor to about one-fifth of the initial value. This peculiar behaviour implies that the permeability of oil sand is very sensitive to shear deformation or grain fabric alteration. Introduction The Athabasca oil sand deposit in northern Alberta, Canada, contains 200 billion m3 of bitumen in place (ERCB 1991). Oil sand is a very dense granular material with interlocked fabric (Dusseault and Morgenstern 1979; Wong 1999). The main mineral composition is dominated by quartz. Its in situ porosity varies from 32 to 35% whereas its maximum porosity can be as high as 45 to 47%. Viscous bitumen filling the intergranular spaces does not affect the geotechnical properties of the material. Steam stimulation is one of the viable methods to extract bitumen from the oil sand ore. Large volume of steam of high pressures (up to 10 MPa) and elevated temperatures (up to 300 °C) are injected into oil sand reservoirs for extraction. Because oil sands are dense uncemented sands, the resulting deformation induced during the recovery processes could cause significant changes in its hydraulic properties. The understanding of its hydraulic properties due to shear deformation is important for design of the steam stimulation recovery processes. Wong et al. (1991) conducted pulse-decay tests to determine changes in absolute and effective permeabilities (to water) of oil sand under conventional triaxial compression. Touhidi-Baghini (1998) used the constant flow rate method to quantify changes in absolute permeability of locked sands specimens under triaxial compressions along various stress paths. They observed that volumetric dilation in triaxial compression could be as high as up to 10% and the permeability could be increased by 5–6 times even though localized multiple shear bands were developed in the specimens. In these conventional permeability tests, the measured hydraulic properties are average responses of the test specimens subject to test boundary conditions, and are significantly influenced by the formation of localized shear bands. They are no longer unique, and become dependent of specimen dimension and test conditions.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».