A Reappraisal of Hydrocarbons Generation and Destruction in the Petroleum Systems of Southern Aquitaine (France).

Summary Sedimentary basins in compressive settings have often complex geological histories and features. Therefore, they present a real challenge in oil and gas exploration. Recent revision of the geodynamic evolution of the North Pyrenees mountain range (France) lead to consider the effects of intense heat flow during the rifting phase prior to compression. We investigated the consequences of this previously unrecognized heating episode on the evolution of the fluids within the petroleum systems on the southern rim of the north Pyrenean foreland basin (Aquitaine basin, France). Taking into account the geodynamic frame, fluids geochemistry was investigated using fluid inclusions from major reservoirs, reservoir gas and oils geochemistry, maturation of the source-rocks through basin modelling and artificial maturation, multiple sulfur isotopes analysis. Results permit to reconsider the maturation history of source rocks, conditions and impact of TSR, secondary migration and reservoir filling as well as to understand the distribution of gas vs petroleum and sourness of fields.