The first discovery of hydrocarbons in the Aquitaine Basin occurred in 1939 at the Saint Marcet Gas Field in the Pyrennees Foothills. Twenty years later the shallow Lacq Oil Field was discovered. Deepening of the third Lacq well led to a blow-out of gas and the ensuing Deep Lacq gas pool discovery. At the time, this gas field was one of the world’s first giants. The latest giant discovery of gas was made in 1965 with the Pau Meillon Gas Field. Total recoverable gas in the area is estimated to be 253 × 10⁹m³ (9 tcf). At the same time gas was discovered in the sub-Pyrenean part of the basin. Significant oil fields were found in the Parentis Basin close to the Atlantic shores.

The main habitat of oil and gas in Aquitaine is the Mesozoic carbonates.

The Jurassic-Cretaceous unconformity is of prime importance for the localisation of the traps. This is because:

1. Jurassic rocks are the main source and

2. Most of the reservoir rocks are located close to the top of the Jurassic formations or at the base of the Lower Cretaceous.

The structural setting and the classification of the reservoirs are more readily appreciated if the paleogeography is understood. The Aquitaine Basin is a marginal type and is strongly influenced by the proximity of the Pyrenean Geosyncline and the Atlantic Margin. The structure of the Basin, based on numerous wells and a profusion of seismic lines sheds new light on some problems related to the birth of the Bay of Biscay and the complex influences of successive Tethys and Atlantic openings.