Thermal and seismic hints for chimney type cross-stratal fluid flow in onshore basins - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Scientific Reports Année : 2018

Thermal and seismic hints for chimney type cross-stratal fluid flow in onshore basins

Résumé

When modelling onshore sedimentary basins, modellers generally assume that semi-permeable layers (aquitards) greatly restrict vertical flow between aquifers. Aquitards are therefore considered as confining media and vertical flow is assumed to take place mainly within localised permeable faults, if any. In the offshore context, however, interpretation of seismic data frequently provides evidence of fluid flow between sedimentary layers via structurally disrupted formations (pervasive fractures) recognised as zones of reduced seismic amplitude and generically called "chimneys". Here we show that chimneys are also present onshore, and that they crosscut confining layers. In the Anglo-Paris Basin, seismic data suggest 1 to 2 km wide zones of disrupted seismic signal spatially correlated to a hitherto unexplained major temperature anomaly of 20 °C. When included in geothermal models using a five-order increase in permeabilities with respect to confining layers, we find that fluid flows vertically through aquifers and confining layers, thereby explaining this major temperature anomaly. Despite the importance of their hydrodynamic and thermal impacts, chimneys-less obvious than faults-have been overlooked as fluid flow paths in many onshore sedimentary basins exploited for their resources. This indicates a clear need for better understanding of pervasive flow paths, especially as the resources and properties of basins (i.e. conventional and unconventional hydrocarbons, geothermal potential, CO 2 storage, nuclear waste repository, drinking water, etc.) are increasingly being harnessed.
Fichier principal
Vignette du fichier
2018_Dentzer_ScientificReports.pdf (3.34 Mo) Télécharger le fichier
Origine : Publication financée par une institution
Loading...

Dates et versions

hal-02323875 , version 1 (21-10-2019)

Licence

Paternité

Identifiants

Citer

Jacques Dentzer, Dominique Bruel, Matthias Delescluse, Nicolas Chamot-Rooke, Laurent Beccaletto, et al.. Thermal and seismic hints for chimney type cross-stratal fluid flow in onshore basins. Scientific Reports, 2018, 8 (1), ⟨10.1038/s41598-018-33581-x⟩. ⟨hal-02323875⟩
115 Consultations
38 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More