A Laboratory Study of Polymer Flooding for Improving Heavy Oil Recovery
Notice bibliographique
Résumé
Abstract Polymer flooding for improving sweep efficiency has been studied extensively in laboratory and tested in fields for conventional oils. From the literature, polymer flooding is not recommended for oils with viscosity higher than 200 mPa.s. Severe viscous fingering during waterflooding of heavy oil leaves a large amount of oil untouched in the reservoir. Polymer flooding could be a potential method for enhanced heavy oil recovery by improving the sweep efficiency. However, how a polymer flooding should be planned for a heavy oil reservoir to make it economically feasible has not been studied. This paper investigated the potential of polymer flooding for heavy oil reservoir using a heavy oil of 1,450 mPa.s. Tertiary polymer flooding tests were performed in both homogeneous and heterogeneous (channelled) sandpacks. Results in homogeneous sandpacks showed that there existed a viscosity range for the injected polymer solution, in which the oil recovery had an evident increase with the increase of polymer solution viscosity. When the viscosity of polymer solution was outside of this range, the increase in polymer solution viscosity resulted in only a small incremental oil recovery. It was also found that the earlier the polymer flooding was applied, the lower the polymer solution viscosity was required to have an obvious increase in tertiary oil recovery. Results in channelled sandpack tests showed that the existence of heterogeneity in porous media greatly lowered the tertiary oil recovery by polymer flooding. These laboratory results will be helpful for the planning of polymer flooding for heavy oil reservoirs. Introduction Thermal method is the most effective technique for heavy oil recovery. However, many reservoirs' conditions restrict the application of thermal techniques, such as thin pay thickness or deep reservoir. Waterflooding of heavy oil reservoir can only achieve a very low oil recovery because of severe viscous fingering. Polymer flooding is a well-recognized technique of mobility control for conventional oils, which could be a potential method for enhanced heavy oil recovery by improving the sweep efficiency. Many laboratory studies and field testes of polymer flooding were reported for conventional oils. Jewett and Schurz1, Chang2 and Needham and Doe3 presented extensive literature reviews on polymer flooding. However, very few literatures4 were concerned with heavy oils. Generally, polymer flooding is applicable for the reservoir with high mobile oil saturation and moderate heterogeneity. It has not been recommended for the case with oil viscosity greater than 200 mPa.s2, 5, 6. Severe viscous fingering during waterflooding of heavy oil leaves large amount of oil in the reservoir untouched. Both technical and economic factors restrict the application of polymer flooding to heavy oil reservoirs with oil viscosity of thousands centipoises. It is not feasible to make the viscosity of the polymer solution to be comparable with that of the heavy oil in the reservoir. For instance, partially hydrolyzed polyacrylamide may not provide high viscosity in high-salinity water even a relatively high concentration is used, especially in the presence of divalent cations (such as calcium) 7.
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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 | 0,000 | 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) | 0,001 | 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
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