| Titre | Geo-synthesis of aliphatic hydrocarbons under localized hydrothermal activity and their 13C depleted isotope signal |
| |
| Auteur | Cesar, J ;
Ardakani, O; Watt, E; Kingston, A; Song, Y; Ahad, J |
| Source | The Gordon Research Conference in Organic Geochemistry; 2022 p. 1-2 |
| Image |  |
| Année | 2022 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20220198 |
| Éditeur | Gordon Research Conferences |
| Réunion | The Gordon Research Conference in Organic Geochemistry; Holderness, NH; US; juillet 31-août 5, 2022 |
| Document | publication en série |
| Lang. | anglais |
| Media | numérique; en ligne |
| Formats | pdf |
| Sujets | hydrocarbures; isotopes de carbone; mécanique des fluides; Formation de Montney ; Zone de cisaillement de Great Slave |
| Programme | Géosciences de l'énergie La coordination du programme |
| Diffusé | 2022 08 08 |
| Résumé | (disponible en anglais seulement)
Western Canada continues to develop hydrocarbon resources, particularly those with lower carbon footprint such as the gas-condensate compound range from
low-permeability reservoirs. Many of these reservoirs have a complex history of fluid migration (e.g. water, hydrocarbons, hydrothermal fluids) before reaching current porosity and permeability conditions, presenting challenges for accurate resource
assessment. Carbon isotope geochemistry has been applied to untangle these complex systems because isotope ratios may record source, temperature and migration characteristics of the fluids. We have recently identified an additional mechanism that
modifies carbon isotope signatures of organics from low-permeability reservoirs in the region. Within a 40 m interval of the Triassic Montney Formation (British Columbia), 13C depleted hydrocarbons (-40 permille to -33 permille) were found in areas
where hydrothermal fluids have introduced high concentration of zinc and cadmium (in sphalerite), among other metals. The n-alkanes were 10 permille more depleted compared with those from areas with lower metal concentration in the same core.
Hydrothermal activity might have initiated from the Great Slave Lake Shear Zone (GSLSZ) during its reactivation in the Late Cretaceous. The GSLSZ has sourced CO2 rich fluids in the Athabasca Basin (Alberta-Saskatchewan) [1, 2], where the CO2 has
precipitated as solid bitumen with delta-13C values of -53 permille via abiotic pathways [2]. A similar abiotic mechanism (e.g. via Fischer-Tropsch reactions [3-5]) may be responsible for isotopically light hydrocarbons in the study core. This and
other possibilities for the identified 13C depleted geo-synthetic compounds will be presented in this study. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette étude présente des preuves de l'abiosynthèse d'hydrocarbures aliphatiques dans la formation de Montney suite à une activité hydrothermale
localisée. Ce phénomène doit désormais être pris en compte lors de la réalisation d'études de géochimie isotopique car il modifie significativement la composition isotopique du carbone des hydrocarbures. |
| GEOSCAN ID | 330484 |
|
|