The Pampa del Castillo-La Guitarra Block is Sipetrol/ENAP's most important asset in Argentina. It contains a mature oil field in the northern San Jorge Basin that requires infill drilling and water injection to maintain production. Pampa del Castillo-La Guitarra is located on the northern flank of the eastern San Jorge Basin. The licence produces from three separate horizons in the Cretaceous Chubut Group. From top to bottom these are Trébol, Comodoro Rivadavia and Mina del Carmen. The depth of the top of the Trebol is about 1,200 metres. The gross pay is around 2,000 metres thick, but this is divided into around 450 separate sand layers.