| Titre | Multiple controls on the accumulation of organic-rich sediments in the Besa River Formation of Liard Basin, British Columbia, Canada |
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| Auteur | Choi, J ; Suk Lee,
H; Kim, Y; Ardakani, O H; Kyung Hong, S |
| Source | Geofluids vol. 2021, 6672043, 2021 p. 1-18, https://doi.org/10.1155/2021/6672043  Accès ouvert |
| Image |  |
| Année | 2021 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200780 |
| Éditeur | Wiley |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1155/2021/6672043 |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Colombie-Britannique |
| SNRC | 94M; 94N |
| Lat/Long OENS | -128.0000 -124.0000 60.0000 59.0000 |
| Sujets | géochimie organique; sediments; Bassin de Liard ; Formation de Besa River ; géochimie; sédimentologie |
| Illustrations | cartes de localisation; diagrammes stratigraphiques; profils; graphiques; graphiques géochimiques; tableaux |
| Programme | Les géosciences pour les nouvelles sources d'énergie Caractérisation des réservoirs de schiste |
| Diffusé | 2021 01 31 |
| Résumé | (disponible en anglais seulement)
The Late Devonian Besa River Formation is an organic-rich shale sequence in Liard Basin, northeastern British Columbia, Canada, with significant natural gas
reserves. High-resolution elemental geochemistry of three long continuous cored intervals of the Besa River Formation was used to better understand the paleodepositional environment of organic-rich intervals in this thick marine shale. The studied
core intervals were divided into five chemostratigraphic units based on organic and inorganic geochemical proxies. The highest total organic carbon (TOC) content (up to 13 wt.%) was identified in the upper part of the Patry member (Unit III) within
the Liard Basin. During the deposition of Unit III, low clastic influx and euxinic bottom conditions mostly contributed to the high accumulation of organic carbon. Moreover, a high productivity and organic influx may have increased organic-rich
basinal sediments, which further depleted the seawater column oxygen content in the presence of a large amount of organic matter. This took place within the oxygen-deficient bottom water from the Patry-Exshaw stratigraphic units. This high TOC
interval was most likely deposited through abundant biogenic silica production by radiolarians, thereby utilizing the supply of nutrients from the upwelling. Sea level change was also an important factor that controlled organic matter accumulation in
the Besa River Formation. The transgression in sea level changed the residence time of the organic matter in oxic zones within the water column, which limited its supply in deeper water; this decreased the TOC content in Unit IV. Before the
deposition, silica production collapsed and was replaced by terrestrial sedimentation of clay minerals in the upper part of the Exshaw member, which caused organic matter dilutions in Unit V (under 5 wt.%). These results provide new insights into the
effects of relative sea level changes on redox conditions, productivity, and detrital flux, which are related to organic matter enrichment patterns and their geographic variations. Unit III is characterized by an organic-rich interval as well as an
abundance of biogenic silica that is closely related to fracturing. Thus, Unit III is expected to have the highest shale gas potential in the Devonian Besa River Formation. The high-resolution geochemical data integrated with well log and/or seismic
data can be used to determine the distribution of the perspective interval for shale gas production in the Liard Basin. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette étude se concentre sur les caractéristiques géochimiques de la formation de Besa River au Dévonien afin de comprendre la formation des
intervalles riches en matière organique dans l'épais schiste marin. Les résultats de cette étude aident à mieux comprendre les caractéristiques du réservoir et les caractéristiques minéralogiques de ces strates prolifiques du bassin de
Liard. |
| GEOSCAN ID | 328162 |
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