Improving Recovery of Liquids from Shales through Gas Recycling and Dry Gas Injection
Notice bibliographique
Résumé
Abstract The objective of this paper is to investigate the possibility of using gas injection to improve liquids recoveries from containers in shale condensate and shale oil reservoirs. Liquids recoveries from shales are known to be very low. A method is proposed to increase these recoveries through gas recycling and by using dry gas that is available within relatively short distances of the shale condensate and oil containers considered in this study. This dry gas is not being produced at this time due to current market conditions. In practice, some shale reservoirs such as the Eagle Ford in the United States and the Duvernay in Canada present the challenge of unconventional fluids distribution: shallower in the structure there is black oil, deeper is condensate and even deeper is dry gas. So the fluids distribution is exactly the opposite of what occurs in conventional reservoirs. Differences in burial depth, temperature, and vitrinite reflectance are used to explain this unique distribution. Ramirez and Aguilera (2014) have shown that fluids in shale reservoirs have remained with approximately the same original distribution (i.e. approximately the same dry gas-condensate contact and approximately the same condensate-oil contact) over geologic time. These fluids are the target of the research results presented in this paper. The investigation involves three basic cases, all of them with horizontal wells. In the first case, a single porosity compositional simulation is used to investigate the possibility of improved liquid recovery from the condensate container by using dry gas injection obtained from the recycling process plus dry gas from the deeper part of the structure. Fluid properties are similar to those of the Duvernay shale. In the second case, dual permeability compositional simulations are used to investigate practical aspects of the condensate container that can lead to improved recoveries in the Eagle Ford shale. Sensitivities are run that include bottomhole pressure (BHP), natural fracture permeability and spacing, hydraulic fracture length and spacing, and distance between parallel wells. Results from dual permeability simulations are compared with dual porosity behavior. Fluid properties are similar to those of the Eagle Ford shale. In the third case, compositional single porosity, dual porosity and dual permeability simulations are used to study the possibility of injecting gas in the oil container. A cyclic huff and puff gas injection is also investigated. Fluids and rock properties are similar to those of the Eagle Ford shale. The study leads to the conclusion that dry gas from deeper shales can be put to good use by injecting it into the middle and upper parts of the structure. In the middle part of the structure there is a container where gas condensate is predominant. In here, a re-cycling injection project allows to inject dry gas stripped from the condensate fluids. This is supplemented with dry gas produced from the deeper part of the structure. In the upper part of the structure there is a container where oil is predominant. In here, injection is implemented using dry gas produced from the deeper part of the structure. Permeability plays a critical role in the case of single porosity simulations. Dual porosity and dual permeability simulations indicate that oil recovery can be enhanced significantly in naturally fractured shales. Diffusion plays a fundamental role on the performance of shale gas injection particularly in the case of naturally fractured shales. It is found that cyclic huff and puff gas injection can help increase oil recovery. To the best of our knowledge, the idea developed in this paper that includes all fluids (oil, condensate and dry gas) present in the same shale structure within relatively short distances of each other has not been published previously in the literature.
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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) | 0,000 | 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 ».