Cinco Presidentes is a business unit consisting of onshore mature fields that lie within Pemex's Southern region. The largest fields are Rabasa Guaricho San Ramon and Cinco Presidentes. The region has been extensively explored and the only remaining prospects can be found in deeper horizons. The Cinco Presidentes fields are all located within the Sureste basin. The Sureste basin is by far the most important oil and gas basin in Mexico. It contains all of Pemex s Southern region onshore fields as well as the offshore fields in the shallow water Bay of Campeche.