INVESTIGATING CROSS FORMATIONAL FLOW OF FLUIDS THROUGH OIL AND GAS WELLS IN ALBERTA AND SASKATCHEWAN, CANADA
Notice bibliographique
Résumé
Deep fluids that are buoyant or have been pressurized due to hydraulic fracturing (HF) or injection related to enhanced oil recovery (EOR) and salt water disposal (SWD) can migrate upwards into other aquifer units, including potable aquifers, through a number of pathways. However, operational considerations typically limit the likelihood of cross formational flow occurring through natural geologic pathways such as faults, leaving anthropogenic pathways, namely wellbores, as the most likely pathway for cross formational flow in most settings. This thesis first evaluates the potential for inter-borehole flow to occur through old abandoned wells in the deep subsurface associated with nearby HF and EOR or SWD operations at three study sites in Alberta and Saskatchewan. It then predicts the occurrence of surface casing vent flow and gas migration (the surface expression of well leakage) in active or suspended wells across Alberta using iterations of the machine learning algorithm, random forest. These two studies share commonality in that the formations located below potable groundwater but above typically targeted oil and gas formations, otherwise known as the intermediate zone, are identified as being critical to understanding both deep well leakage and the surface expression of well leakage. \nResults indicate that old abandoned wells at the study sites surveyed typically leave several intermediate zone aquifers commingled between abandonment plugs, increasing their susceptibility to the effects of nearby HF and EOR or SWD operations. For the surface expression of wellbore leakage the intermediate zone has generally been identified by previous studies as the origin for the majority of stray gas samples analyzed. While a modest predictive accuracy of 73% to 77% was achieved using random forest algorithms on a test dataset of wells across all of Alberta, predictive performance could likely be improved by including more predictors previously identified as being strongly correlated with well leakage that are related to the intermediate zone (e.g. well cement tops). In both studies the results can help shape future government regulations and policy but future field work on the intermediate zone is needed to improve our understanding of the integrity of oil and gas wells, the extent to which intermediate zone aquifers may be commingled by old abandoned wells, and by verifying the veracity of the existing database on the occurrence of SCVF/GM.
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 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 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,001 |
| Communication savante | 0,000 | 0,002 |
| 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 ».