| Titre | Organic petrography and thermal maturity of the Paskapoo Formation in the Fox Creek area, west-central Alberta |
| Télécharger | Téléchargements |
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| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | Ardakani, O H |
| Source | Commission géologique du Canada, Dossier public 8903, 2022, 20p., https://doi.org/10.4095/330296  Accès ouvert |
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| Année | 2022 |
| Éditeur | Ressources naturelles Canada |
| Document | dossier public |
| Lang. | anglais |
| DOI | https://doi.org/10.4095/330296 |
| Media | numérique; en ligne |
| Formats | pdf |
| Province | Alberta |
| SNRC | 83K/02; 83K/03; 83K/04; 83K/05; 83K/06; 83K/07 |
| Région | Fox Creek; Tony Creek |
| Lat/Long OENS | -118.0000 -116.5000 54.5000 54.0000 |
| Sujets | Paléogène; Paléocène; ressources pétrolières; hydrocarbures; capacité de production d'hydrocarbures; filons de charbon; roches mères; ressources en eau souterraine; aquifères; pollution de l'eau
souterraine; pétrographie; maturation thermique; puits d'observation; géochimie organique; pyrolyse; effets sur l'environnement; gaz d'origine biologique; méthane; réflectance de la vitrinite; géologie du substratum rocheux; lithologie; roches
sédimentaires; grès; schistes; siltstones; sediments; tills; Formation de Paskapoo ; combustibles fossiles; géochimie; hydrogéologie; Sciences et technologie; Nature et environnement; Phanérozoïque; Cénozoïque; Tertiaire |
| Illustrations | diagrammes stratigraphiques; tableaux; croquis cartographiques; profils; graphiques; photomicrographies; diagrammes |
| Programme | Géosciences environnementales Impacts potentiels des activités liées au développement gazier et pétrolier sur les aquifères non salins, Fox
Creek |
| Diffusé | 2022 07 05 |
| Résumé | (disponible en anglais seulement)
The Paskapoo Formation, which ranges in age from middle to upper Paleocene, is the major shallow aquifer in Alberta. This study is part of a larger GSC-led
study on the potential environmental impact of hydrocarbon development in the Fox Creek area (west-central Alberta) on shallow aquifers. Fox Creek is located near the northern limit of the Paskapoo Formation. In addition to the underlying
organic-rich source rocks in the study area, including the Duvernay Formation that is currently exploited for hydrocarbon resources, the Paskapoo Formation contains organic-rich intervals and coal seams. In order to investigate any potential internal
hydrocarbon sources within the Paskapoo Formation, ninety-seven (97) cutting samples from the formation obtained from eight shallow monitoring wells (50-90 m) in the study area were studied for total organic carbon (TOC) content, organic matter
composition and thermal maturity of coal seams using programmed pyrolysis analysis and organic petrography.
The TOC content of all samples ranges from 0.2 to 8.8 wt. %, with a mean value of 0.95 ± 1.6 wt. % (n=97). The Tmax values of studied
samples range from 347 to 463 °C, with a mean value of 434 ± 20 °C that suggest a range of thermal maturity from immature to peak oil window. The random reflectance (Rr) measurement and fluorescence microscopy on eighteen (18) selected samples with
TOC content > ~1 wt. % shows a mean Rr value of 0.27% and 0.42% for the overlying till deposits and the underlying shallow depth sandstone, siltstone, shale and coal seams respectively, indicating a low rank coal ranging from lignite to
sub-bituminous coal. Blue to green and yellow fluorescing liptinite macerals further confirmed the low maturity of studied samples. The low S2 yield of a large part of the samples (65%) resulted in unreliable Tmax values that overestimated the
thermal maturity.
Although the organic matter in the studied intervals are immature, exsudatinite, as secondary liptinite maceral, was observed in samples from the lower parts of the studied monitoring wells. Exsudatinite generally derives from
the transformation of sporinite, alginite, resinite and varieties of vitrinite, which is a resinous or asphalt like material. Considering the thickness and distribution of coal seams in the studied samples, it is unlikely the exsudatinite will be a
major source for aquifer hydrocarbon contamination in the study area. Additional stratigraphic studies and molecular geochemical analysis could provide an estimate of the total volume of possible organic compounds contribution to the aquifer in the
study area. Due to the presence of coal seams in the studied intervals of the Paskapoo Formation, it is important to investigate the possibility of biogenic methane formation in Paskapoo shallow aquifers. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette étude fait partie d'une étude plus vaste sur l'impact environnemental potentiel du développement d'hydrocarbures non conventionnels dans
la région de Fox Creek en Alberta sur les aquifères peu profonds. En plus des roches mères riches en matières organiques sous-jacentes dans la zone d'étude, la formation de Paskapoo contient des intervalles riches en matières organiques et des filons
de charbon. Afin d'étudier toute source interne potentielle d'hydrocarbures dans la formation de Paskapoo, on étudie sept échantillons de coupe nocturne de la formation obtenus à partir de huit forages peu profonds dans la zone d'étude afin de
mesurer la teneur en carbone organique total (COT), la composition de la matière organique et la maturité thermique des filons de charbon dans la formation de Paskapoo en utilisant l'analyse par pyrolyse programmée et la pétrographie
organique. |
| GEOSCAN ID | 330296 |
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