The Influence of Organics on Supercritical CO2 Migration in Organic-Rich Shales
Notice bibliographique
Résumé
The Bakken petroleum system is a world-class oil play with oil-in-place estimates in the hundreds of billions of barrels. Despite the resource potential, oil recovery factors are low, typically less than 10%. Efforts to evaluate mechanisms to increase oil recovery have focused on the use of supercritical carbon dioxide (CO2) for enhanced oil recovery (EOR) with the added benefit of associated geologic storage of CO2. This work describes a series of laboratory-based tests to evaluate the efficacy of CO2 for EOR and to better understand the controlling mechanisms of CO2 permeation in Bakken rock samples. Static extraction tests were performed on rock samples representative of the Bakken reservoir (siltstone) and source rocks (Upper and Lower Bakken shales). A dynamic CO2 injectivity test was also performed on an unfractured Bakken shale sample that was confined at reservoir pressure. In conjunction with the extraction tests, a suite of standard and advanced characterization techniques were used to better understand the rock fabric, pore and fracture networks, and the organic matter (OM) content of the samples, including field emission scanning electron microscopy (FESEM) imagery, focused ion beam SEM (FIBSEM), and extended slow heating (ESH) Rock-Eval analysis. The extraction test results demonstrated recovery of residual oil in the tight siltstone samples comprising the reservoir (recovery values approaching 100%) and also in the shale source rocks, in which oil recovery from 11-mm-diameter rods ranged from 12% to 65% after 24 hours. Analysis of samples pre- and post-CO2 extraction using the Rock-Eval ESH method confirmed the results of the CO2 extraction tests. FESEM imagery of the Bakken shale samples revealed the presence of fractures located within the OM, many of which appear to be connected and could provide a mechanism for CO2 transport into the OM and subsequent extraction of crude oil. Image-based analysis of the FESEM and FIBSEM imagery suggested that the majority of the porosity in the shales was OM-hosted and that much of the pore networks were connected. The results of this work revealed that CO2 is able to permeate samples of unconventional reservoir and shale source rocks much more readily than expected, resulting in significant recovery of residual oil. The mechanism of permeation within the organic-rich shales appears to be within OM-hosted fracture networks and possibly through nano-scale porosity associated within the samples’ solid bitumen. The implications of this work suggest that organic-rich source rocks may be a viable target for CO2-based EOR, with the added benefit of long-term CO2 storage via adsorption and absorption.
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Comment cette classification a été obtenuedéplier
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 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| 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) | 0,000 | 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 ».