- Operator: Total
- Country: France
- Location: southwest France near the Pyrenees Mountains
- Production start:
- Type: Oil
- Estimated Reserves: OOIP was about 125 MMbbl
- Production Volume:
- 1950 - Lacq Superieur Oil Field is discovered
- 1977 - A steam-drive pilot was initiated
- The saturated horizon is the Lower Senonian limestone of the Upper Cretaceous age. Overburden is provided by Campanian argillaceous, calcareous rocks or by Paleocene marls. The reservoir is limited by underlying carbonates of Turonian, Cenomanian, and Albo-Aptian ages. These structures form a huge aquifer, more than 6,500 ft (2000 m) thick, that maintains the pressure of the oil reservoir.
- The Lacq Superieur structure is an anticline with a northwest/southeast axis. The oil-bearing area is about 1,400 acres (5.7 x 106 m2). Depth is 1,970 to 2,300 ft (600 to 700 m), and thickness is about 400 ft (120 m). Reservoir limestones exhibit two facies with very different characteristics: (1) The central portion contains very fractured, occasionally karstic, dolomites with a matrix porosity of 10 to 15% and a very low matrix permeability (about 1 md). However, the high fractionation of this zone results in a very high productivity, (2) The northwest and southeast parts of the field are constituted of calcareous rocks with an average porosity of 20% and permeability of 1 to 10 md. This facies has only some microfissures, and productivity is low.
- The OOIP was about 125 MMbbl (20 x 106 m3), of which 17% currently is produced.