Compositional Changes During Vapex (Vapour Extraction) Operations in Heavy Oil Pools
Notice bibliographique
Résumé
Abstract During Vapex (Vapour Extraction) operations for heavy oil recovery, a condensable solvent (such as propane or CO2) is injected into the reservoir via a horizontal injector and mobilized oil is drained via a horizontal producer placed directly underneath it. The solvent is chosen such that it is close to its dew point under reservoir conditions. Mixing with this solvent significantly reduces viscosity of the heavy oil. Theoretical treatments assume the oil to be 'black' i.e. no changes to the oil occur, other than viscosity reduction due to localized dissolution of the solvent. However, one observes several compositional changes during Vapex experiments in the laboratory, especially when working with conventional heavy oils such as those from the Lloydminster Area of Canada. Via physical model studies involving different heavy oils, it was seen that compositional changes occur in the oil being produced as well as, in the oil still resident within the model. These include solvent extraction of vaporizable components of the heavy oil, especially in the early stages of Vapex; subsequent produced oil was seen to be progressively heavier. These effects are more than compensated if de-asphalting of the oil occurs, as was observed in many laboratory Vapex experiments. Since the process is dynamic (unsteady state), oil quality and rates change with time. These changes may also affect price one obtains for the oil produced (function of API gravity and sulfur/ metal contents). Regarding deasphalting of the oil produced, it makes a lot of technical and economic sense to focus on ways of improving oil extraction rates down-hole by partially upgrading the oil in-situ and, on improving commodity quality in surface facilities once the heavy oil-solvent mixture has been produced, prior to its shipment to the refinery/ up-grader. Various aspects of compositional changes during Vapex are discussed using data from physical models; glass micro-models and MRI Images obtained during different Vapex experiments. Introduction In Vapex (Vapour Extraction) operations for heavy oil recovery, a condensable solvent (e.g. propane or CO2) is injected into the reservoir via a horizontal injector and mobilized oil is drained via a horizontal producer placed directly underneath it. The solvent is chosen such that it is close to its dew point under reservoir conditions and resulting solvent-oil mixture in vicinity of the vapour chamber, has significantly lower viscosity as compared to the native oil. The main driving mechanism is gravity to help drain the oil thus mobilized1 (having reduced viscosity) as shown in Figure 1. Theoretical treatments of Vapex assume the oil to be 'black', i.e. no changes to oil occur, other than viscosity reduction due to localized dissolution of the solvent. However, one observes several compositional changes occurring in the laboratory during Vapex, especially when working with conventional heavy oils such as those from the Lloydminster area. These include progressive extraction (into the injected solvent) of light hydrocarbon components of oil and asphaltene deposition. Upon contact with the solvent vapour, vaporizable components of oil are extracted into the vapour phase and/or transfer of some of the solvent into the oil phase occurs.
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 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 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
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 ».