Geological Characterization and Evaluation of Reservoir Quality in The Montney Formation in West-Central Alberta
Notice bibliographique
Résumé
Hydrocarbons hosted in low-permeability siltstones of the Montney Formation in western Canada are currently being exploited with multi-staged fractured horizontal wells. However, a significant challenge for development is effectively targeting zones for lateral placement and hydraulic fracture stimulation within the typically thick (200-350 m) gross Montney interval. Moreover, at the vertical resolution of standard well logs, the Montney display limited variability, with significant cm-scale changes in geological properties –which can affect reservoir quality– being undetectable. Therefore, this thesis, focused on the Kakwa Field in west-central Alberta, presents a comprehensive characterization of small- and large-scale variations in geological properties using core and drill cutting samples. A high-resolution data set (2.5 cm spacing), including profile measurements of elemental composition, permeability, and rock hardness measured on a complete Montney core, led to the identification of potential geological controls on reservoir quality. The presence of fine-grained laminations (organic-rich), dolomite and anhydrite- cementation, and the abundance of clays, pyrite, and organic matter, have a negative effect on the permeability of Montney reservoirs. The high-resolution data set also allowed the identification of organic-rich mudstone beds throughout the Middle Montney member. Although the organic-rich mudstone facies are interbedded with siltstone facies throughout the upper Middle Montney, they have been generally overlooked due to their small thickness (<10 cm). Through the integration of detailed sedimentologic core descriptions, petrographic evaluations, and laboratory analyses, significant findings were made from the organic-rich mudstone beds: 1) they host primary organic matter (kerogen Type II) with petroleum generative potential. Hence, organic-rich mudstone beds are proposed as partial contributors to the hydrocarbons hosted in relatively organic-lean adjacent siltstone beds; 2) based on sedimentological evidence (e.g., poorly sorted and clay-rich matrix, lack of sedimentary structures), their deposition is associated with hypopycnal flows, highlighting the importance of fluvial processes in the sediment transport of the Montney Formation; 3) they have low hardness (which can be translated into low stiffness and/or rock strength), and, when interbedded with higher-hardness beds, can potentially act as weak interfaces causing blunting of fractures, thus impacting hydraulic fracture growth. The observations gathered from core data were directly applied in a case study that showcases the integration of geological, petrophysical, and geomechanical properties derived from drill cutting samples, well logs, and drilling data, to identify superior reservoir quality intervals along a Montney horizontal well. Significant m-scale heterogeneities were observed in reservoir properties along the 2.5 km length of the well. Superior reservoir quality intervals were associated with predominantly massive, porous siltstone facies, and relatively inferior reservoir quality intervals were associated with either dolomite-cemented facies or laminated siltstones. The primary outcomes from this characterization served as input for a semianalytical model built to predict hydraulic fracture stage performance (as evaluated from predicted hydrocarbon production). Motivated by the importance of rock types to reservoir quality characterization along horizontal wells, an image processing workflow to identify, classify, and quantify rock types using SEM images of drill cuttings is proposed; importantly, a fully labeled data set containing more than 16,000 SEM images of drill cuttings is open-sourced. Lastly, a laboratory-based study was conducted to compare the effectiveness of three methods to clean drill cuttings contaminated with oil-based muds. The reviewed cleaning methods involve the use of 1) an organic solvent (dichloromethane), 2) a furnace (180 °C), and 3) a trademark surfactant. Overall, solvent cleaning was determined to be the best method to remove drilling mud contamination, including the oil and mud fines.
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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 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,002 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| 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 ».