Notice bibliographique
Résumé
Abstract Wormholes are believed to be generated during the initial phase of cold production and are responsible for enhanced production rates when sand cuts are reduced to their minimum. In this work, we present a theoretical model describing sand and fluids flow within a wormhole uniformly filled with sand. This model is based on the Darcy-Brinkman equations for fluids in mobile sand, a rheological equation for sand motion, and conservation laws. Velocity profiles of sand and fluid are calculated and used to establish the relation between the pressure drop and the flow rates. An estimation of wormhole size is also provided. This model provides understanding of the basic flow behavior in a wormhole during the massive sand production stage of cold production. It also provides some key parameters for field scale numerical simulations of cold production. Viscous Drag and Critical Radii The detailed mechanism of sand erosion is a complicated subject. It involves the geomechanical properties of the sand, the rheological properties of fluids, and the nature of sand-fluid and fluid-fluid interactions. However complicated, the key to flux erosion is that it happens when the drag force overcomes the resistance of the sand matrix. The drag force should be mainly the viscous body force due to flow of fluids through the sand matrix (Darcy flow). The resistance of the sand matrix is mostly a surface force. It is due to cohesion, adhesion and contact forces. It holds a chunk in place against the body force. The thickness of this chunk, ?, can be as small as the averaged grain size or orders of magnitude larger, depending on the sand properties and the viscous body force. In the former limiting case, "raining" of sand grains into a cavity occurs. In the latter limiting case, microcracks in the sand matrix may be observed just before the erosion. Assuming fluid flow into a cavity of radius R, the above-stated criterion can be expressed as: Equation (1) (Available In Full Paper) where σ is the surface strength of the sand, and P the fluid pressure. The geometry of the wormhole is assumed to be comprised of a straight cylindrical tube, with a hemispherical cap at the end, as illustrated in Figure 1. Computed tomography images(1) of the wormhole tip show that it is more pointed in reality, as shown by the dashed line in Figure 1. The assumption of hemispherical flow at the tip, however, seems reasonable. For a spherical geometry, FIGURE 1: Influx of fluid into a wormhole. The dashed line represents the actual shape of a wormhole tip (Available In Full Paper) the pressure gradient is inversely proportional to the square of the radius if the fluid is incompressible. Therefore, we can integrate the right-hand side of the inequality (1). Denoting the reservoir pressure as Pre, the pressure at the wall of the cavity as P, and the radius of the drainage zone beyond which the reservoir retains its original reservoir pressure as Rs, we find: Equation (2) (Available In Full Paper)
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 | 0,003 | 0,001 |
| 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 | 0,001 |
| 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 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 ».