Geotechnical Centrifuge Experiments to Improve Understanding of Sand Production from Heavy Oil Reservoirs
Notice bibliographique
Résumé
Since the 1990’s, Cold Heavy Oil Production with Sand (CHOPS) has been a common practice in Western Canada where sand can be easily mobilized from weakly cemented sandstones. The more sand produced, the greater the oil recovery, with recovery factors of 10% being typical. In recent years, operating companies have enhanced recovery in reservoirs previously operated using CHOPS by applying thermal and/or chemical methods; however, effective implementation of these methods requires an improved understanding of sand production mechanisms. Numerous field-based, numerical, and laboratory modelling studies have been completed to better understand the shape of the voids that form within heavy oil reservoirs during CHOPS, sand transport mechanisms, and CHOPS impact on production rate. The objective of this research was to design and implement a laboratory testing system to investigate these subjects.\nA purpose-built geotechnical centrifuge model was used for this research, with a sandpack of dense, uncemented sand representing the reservoir. The results demonstrate that the predominant sanding mechanism is the development of a cone-shaped cavity at the top of the sandpack, both with stiff (steel) and compliant (clay) caprock. The results also demonstrate that erosion channels may develop around the cavity, in cases where flow rates near the top of the sandpack are greater than flow rates at depth; however, with the presence of a flexible caprock and uniform radial flow, this effect can be nullified. In addition, the results for one of the experiments, in conjunction with numerical modelling, suggest that a wormhole may form during seepage in the upper part of the reservoir where in-situ stresses are relatively low, though it might collapse once seepage is ceased. Such wormholes may have been a major cause of the high flowrates observed during the tests after sand production, enhanced to some extent by dilation-induced increase in hydraulic conductivity in the near-well and near-cavity areas. Moreover, results obtained using two-phase fluid saturations (water and oil) suggest that capillary pressures increase the effective strength of the sandpack, which reduces the tendency of sand failure as was observed in deep perforated zones in experiments conducted using single-phase oil saturation. The practical implication of this work is the suggestion that it may be possible to improve the effectiveness of enhanced recovery operations if heated fluids/solvents are injected into the deeper, less disturbed part of the reservoir in order to avoid premature breakthrough (production) of injected fluids.
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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 | 0,001 | 0,001 |
| 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 | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 ».