Investigation of longitudinal and transverse dispersion in porous media
Notice bibliographique
Résumé
Miscible displacement processes are increasingly feasible methods for the recovery of oil from depleted reservoirs as an enhanced oil recovery (EOR) method. However, a fundamental understanding of the dependency of transport phenomenon to medium properties and their consequent impact on oil recovery efficiency is lacking. Moreover, it is generally believed that miscibility may repeatedly develop and break down in a reservoir due to dispersion arising from velocity and reservoir heterogeneity. Thus, miscible processes are assumed to be dependent on the pore geometry of the reservoir. The current research uses mathematical and unique experimental approaches to investigate miscible displacement in two-dimensional media with focus on pore structure to comprehend the relationship between the transport properties to its pore structure. Transport phenomena significantly influence EOR efficiency and this raises the importance of dispersion and miscibility. The mathematical section of this research uses a statistical oriented mathematical approach to investigate miscible displacement assuming various pore properties to comprehend the relationship between dispersion during miscible displacement and the pore structure. This study focuses on examining the dependence of dispersion in both the longitudinal and transverse directions on heterogeneity and pore geometry using statistical models. The pore element is defined by adjustable distribution functions indicating tortuosity and connectivity of the porous medium. Using random walk theory that assumes the mass transfer occurs as a sequence of discrete physical events as particles move between a series of discrete pore elements, the stochastic functions are used to develop a model to estimate the mechanical dispersion properties of the porous media. The introduced model decouples dispersion in the longitudinal and transverse directions and shows a more specific relationship between dispersion and pore size distribution. An analytical approach is applied to model miscible displacement in a fractured medium to study the effect of velocity on the magnitude of mechanical dispersion. Various displacement scenarios are assumed to find the the effect of pore properties on dispersion. Results illustrate a strong dependence of mechanical dispersion on pore properties of the medium. Both longitudinal and transverse dispersion coefficients increased by increasing the velocity and heterogeneity ratio. In the experimental section, a new experimental approach has been developed to estimate the average longitudinal and transverse dispersion co- efficients in a homogeneous anisotropic porous medium during miscible displacement. A series of miscible flooding tests are conducted and studied. Traditionally, most studies of miscible injection have focused on recovery and mechanism of the method and Peclet number that have been used to find the dispersion and diffusion coefficients from a mathematical correlations. This study utilizes a unique method to estimate the mass transfer properties. A unique image processing tool is developed and used to analyze the developing mixing zone in the process and consequently processed images are used to collaborate with a developed Bayesian estimator tool to fit the dispersion coefficients in analytical solution of Advection-Diffusion Equation (ADE). The de- tails of the approach are explained and obtained images are analyzed and interpreted. The results confirm the strong dependency of the velocity of the displacing fluid and dispersion coefficients in both longitudinal and transverse directions. The effects of anisotropy on miscible mass transport are investigated in this study too.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,001 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,001 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 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 source (Gemma direct ou Codex distillé), 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 ».