Using multiple data sources to assess whether oil and gas activities have affected water resources in a Western Canada watershed
Notice bibliographique
Résumé
A multidisciplinary environmental project was conducted between 2019 and 2024 to assess the potential impacts of industrial activities and, in particular, oil and gas (O&G) development, in the Fox Creek area (Alberta, Western Canada). Fox Creek was selected because this region has been intensively developed for hydrocarbons over the past 60 years, first for conventional resources, then for unconventional shale gas which involves hydraulic fracturing. The various components of the project included geological, shallow and deep geophysical, geomechanical, geochemical, hydrogeological, as well as air photos and remote sensing studies, which fed into each other. The study area covers 700 km2 and is mainly forested. Despite its small size, it includes over 800 O&G historical and producing wells and 2,300 km of seismic lines. The regional shallow aquifer is the Paleogene Paskapoo Formation, a fluvial unit comprising meter to decameter-thick sandstone-fill channels cut into a mudstone, siltstone and shale continental plain succession that also includes coal seams. By its very nature, this formation is highly heterogeneous and consequently exhibits a wide range of hydraulic conductivities and yields. The aim of this project was to study an industrial region holistically, from the surface to the gas-rich unit using both direct and indirect data, in order to obtain different lines of evidence for assessing cumulative effects.The variable hydraulic properties of the Paskapoo Formation are due to both its architecture and diagenesis. The latter has led to the development of preferential pathways in poorly consolidated sandstone-fill channels with irregularly distributed, meter-thick, highly calcite-cemented sandstone beds. The dissolution / cementation events have formed a framework which controls flow in conjunction with the fracture network mainly consisting of bedding planes. Data/results from water levels, yields, estimated vertical recharge, petrophysical analyses, borehole geophysics and geochemistry indicated that a significant portion of the water flowing through the watershed originates from the foothills of the Rocky Mountains, a mountain range located approximately 150 km to the southwest. The integrated results of geology, hydrogeology and geomechanics have shown that the aquifer's vulnerability to both surface and deep activities is low. Indeed, geochemistry revealed no impact on surface or groundwater quality. Nevertheless, the study of landscape evolution over time revealed that around 36% of forests have disappeared in the past few decades in the study area, while another study revealed that there may be significant differences between the various water budget components in undisturbed and disturbed (e.g. seismic lines) areas, including a decrease in aquifer recharge in disturbed areas. This project has shown that, although the quality of water resources does not seem to be affected, probably largely due to the favorable geological/hydrogeological context, human activities do have an impact on the water resource apportionment, affecting, among other things, vegetation and notably its recovery in disturbed areas.
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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 | 0,002 | 0,005 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,004 | 0,011 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,003 | 0,001 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,001 |
| 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 ».