Abstract: The Petroleum Systems of the Aquitaine Foreland

Jean-Jacques Biteau, Jean-Marie Masset, Michel Le Vot, Remy Martin, Alain Le Marrec

The Aquitaine basin of southwestern France lies in the foreland of the Pyrenean Fold and Thrust Belt. Since the first gas production in 1939, the area has produced as of December 1994, around 290 Gm3 of gas, 13,6 MT of condensates and 12,7 MT of oil.

The hydrocarbon charge of the traps, the migration paths and the different types of fluids have been recently studied in detail by Elf. The parameters of the Aquitaine petroleum systems are therefore completely reevaluated.

In this framework the hydrocarbon traps are related to inherited structures linked to the Early Cretaceous extension (tilted blocks of Jurassic and Barremian carbonates) and to the associated salt tectonics (such as erosional pinch outs of the Jurassic and Barremian reservoirs). Some of these features have then been locally reversed within the Pyrenean Fold and Thrust Belt and Foreland area.

In this complex structural setting, conventional 2D seismic data revealed poor quality for a precise field geometry. From 1987 to 1992, over 1500 km2 of 3D seismic were acquired in the area with the purposes of field development and as well as oil and gas exploration. The good subsurface data (3D and 2D reinterpretations) have allowed us to define the distribution, geometries and relationships of the different tectono-sedimentary units as well as of the structures associated to the petroleum traps. This work has greatly enhanced the knowledge of the whole area in helping to define its geodynamic evolution based on the results of hydrocarbon generation models and on several organic geochemical and fluids data.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France