Guillaume BARRÉ

Gases reactivity (H2S, CH4, CO2, H2) in the Aquitaine basin

Supervisors:
Guilhem Hoareau
Université de Pau et des Pays de l’Adour (UPPA), France
Éric Gaucher – Total, CSTJF, Pau

Major Results

H2S is generated by TSR in the entire area and occurred in the deepest/hottest parts of the basin. Coupling the analysis of different stable isotopes associated with structural studies is essential to determine the exact source and path of hydrothermal fluids.

Abstract

The Aquitaine basin presents oil/gas fields with large amount of H2S (up to 20mol%) and hydrothermal fluid occurrences (overpressure, breccia…). During this study, different geochemical analyses were used: multiple sulfur isotopes, stable isotopes (δ13C, δ18O), fluid inclusions, 87Sr/86Sr. All these results were compared to the structure of the basin to better constrain the exact source and path of hydrothermal fluids. In particular, multiple sulfur isotope analysis demonstrated that, as assumed, Thermochemical Sulfate Reduction (TSR) was responsible for the large amount of H2S in the area.

 

When it was coupled to the basin structure, it appeared that TSR occurred in the entire Chaînons Béarnais and in all the deepest parts of the Arzacq basin. With this comprehensive study, a relative timing was proposed for TSR occurrence and its associated hydrothermal circulations: 1) TSR occurred together with hydrocarbons generation during the rifting; 2) TSR-related H2S accumulated under the Sainte-Suzanne marls; 3) during compression H2S migrated as hydrothermal fluid.

Timeline of fluids evolution in the Aquitaine basin including the thermochemical sulfate reduction (TSR)

Epigenic vs. hypogenic speleogenesis governed by H2S/CO2 hydrothermal input and Quaternary icefield dynamics (NE French Pyrenees).

Epigenic vs. hypogenic speleogenesis governed by H2S/CO2 hydrothermal input and Quaternary icefield dynamics (NE French Pyrenees).

Dimitri Laurent, Christophe Durlet, Guillaume Barré, Patrick Sorriaux, Philippe Audra, Pierre Cartigny, Cédric Carpentier, Guillaume Paris, Pauline Collon, Thomas Rigaudier, Jacques Pironon, Eric C. Gaucher. Epigenic vs. hypogenic speleogenesis governed by H2S/CO2 hydrothermal input and Quaternary icefield dynamics (NE French Pyrenees). Geomorphology 387 (2021) 107769

keywords: Hypogenic sulfuric and carbonic acid, speleogenesis, Multiple sulfur isotopes, Thermal water geochemistry, Pyrenees

DOI: https://doi.org/10.1016/j.geomorph.2021.107769

Impact of geodynamics on fluid circulation and diagenesis of carbonate reservoirs in a foreland basin: Example of the Upper Lacq reservoir (Aquitaine basin, SW France).

Impact of geodynamics on fluid circulation and diagenesis of carbonate reservoirs in a foreland basin: Example of the Upper Lacq reservoir (Aquitaine basin, SW France).

Elias Bahnan, A., Carpentier, C., Pironon, J., Ford, M., Ducoux, M., Barré, G., Mangenot, X., Gaucher, E.C. (2020). Impact of geodynamics on fluid circulation and diagenesis of carbonate reservoirs in a foreland basin: Example of the Upper Lacq reservoir (Aquitaine basin, SW France), Marine and Petroleum Geology (2019).

keywords:Carbonate diagenesis, Pyrenees, Aquitaine foreland basin, Upper Lacq reservoirs, Fluid inclusions, Basin modeling, Dolomitization, Hydrothermal fluids

DOI: https://doi.org/10.1016/j.marpetgeo.2019.08.047

Hydrothermal fluid circulations in the western Pyrenees: new data on stable isotopes, in-situ gas analysis and fluid inclusions.

Hydrothermal fluid circulations in the western Pyrenees: new data on stable isotopes, in-situ gas analysis and fluid inclusions.

Barré, G., Elias Bahnan, A., Motte, G., Ducoux, M., Hoareau, G., Laurent, D., Gaucher, E.C. (2019) Hydrothermal fluid circulations in the western Pyrenees: new data on stable isotopes, in-situ gas analysis and fluid inclusions. E3S Web. Conf. 98, 4.

keywords:  Hydrothermal circulation, Western Pyrenees, H2S

DOI: https://doi:10.1051/e3sconf/20199801001