Surfactant and Surfactant-Polymer Effects on Wettability and Crude Oil Liberation in Carbonates
Notice bibliographique
Résumé
Abstract Surfactants and polymers are used in enhanced oil recovery (EOR) to reduce interfacial tension and increase the viscosity of displacing fluid, respectively. For oil-wet to mixed-wet systems, especially carbonates, which tend to be heavily fractured, wettability becomes a key parameter that strongly affects oil recovery. Therefore, studying the impact of surfactant and surfactant-polymer chemicals on carbonate wettability is important to understand the underlying mechanisms responsible for incremental oil recovery in surfactant-polymer flooding. In the present study, liberation kinetics of crude oil from carbonate surfaces were investigated by using a liberation cell at both ambient and elevated temperatures (70°C). The liberation cell is equipped with an optical microscope for monitoring oil liberation. In addition, a custom-designed integrated thin film drainage apparatus (ITFDA) was used to measure adhesion forces between carbonate substrates and crude oil droplets. The chemical solutions were prepared in a representative high salinity brine. Two types of surfactants: a nonionic and an amphoteric were used. A sulfonated polyacrylamide polymer was selected as it was previously proven to be tolerant to both high salinity and high temperature conditions. The chemical solutions were prepared at dilute concentrations of 1000 mg/L and 500 mg/L for the surfactant and polymer, respectively. Besides the main experimental data, i.e., adhesion forces and liberation kinetics, interfacial tensions and zeta potentials were also measured for different solutions. In the zeta potential tests, carbonate particle suspensions in brine, surfactant, polymer and surfactant-polymer solutions were used. Oil liberation from carbonate surface is the lowest with brine and the polymer increased the degree of oil liberation. The amphoteric surfactant showed better efficiency to liberate more crude oil from carbonate surface over the nonionic surfactant. Polymer and surfactant addition to brine resulted in an oil liberation degree that is much higher than those obtained by each of the chemicals when applied individually. For solutions containing brine, polymer, surfactant, and surfactant-polymer, oil liberation degree increased at elevated temperature. Adhesion forces were very consistent with the observed oil liberation results. Adhesion force was strongest in brine, and both the polymer and surfactants further lowered the adhesion force. Accordingly, the lower adhesion force between carbonate and crude oil in aqueous solutions containing surfactant and polymer contributed to the increased oil liberation. The higher oil liberation degree obtained with the amphoteric surfactant can be explained by its ability to lower oil/water interfacial tension by two to three orders of magnitude. In addition, the surface charge of oil droplets and carbonate particles were found to be increasingly negative in aqueous solutions containing surfactant and polymer, thereby contributing to enhanced wettability alteration in crude oil-brine-carbonate systems. These microscale results indicate that trapped-oil mobilization in carbonates is governed by both wettability and capillarity; in other words, wettability alteration as well as reduction in oil/water interfacial tension would lead to increased oil liberation. This experimental study has characterized, for the first time, surfactant, and surfactant-polymer effects on wettability and crude oil liberation in carbonates. Such enhanced understanding obtained on the microscale interactions of surfactant, and surfactant-polymer chemicals at carbonate/brine/oil interfaces can provide some guidance on how to optimize EOR formulations for carbonate reservoirs.
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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 | 0,000 | 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
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 ».