With a cumulative production of over 450 MBO and 500 GCFG, the Catatumbo Basin is the second pioneer of the oil exploration in Colombia. Exploration activities began with the signing of the Barco concession in 1920 that shares, with the Middle Magdalena Valley, the first commercial oil production in Colombia. The main fields discovered up to now are: Tibú-Socuavo, Carbonera, Sardinata, Río Zulia, Petrólea and Puerto Barco.
Pelitic rocks of Cretaceous age, from La Luna, Capacho, Tibú and Mercedes formations, are widely distributed throughout the basin. They are distributed regionally in the Maracaibo Basin as well and they are considered among the richest sources of oil in the world (Figure 2). La Luna Formation is the main source unit of the basin and has a thickness of about 200 feet. The TOC content varies from 1.5% to 9.6%, with average of 3.8%. La Luna Formation is currently in the hydrocarbon generation window.
Three migration systems have been documented in Catatumbo Basin, allowing the accumulation of hydrocarbon on traps formed during the Late Miocene-Pliocene interval. The lithologic character of the very fine grained sandstones of the Cretaceous sequence and the homogeneity of the limestones have favored the occurrence of “in situ” or with very short migration pathway entrapments. However, lateral migration along sandstone bodies and vertical migration along fault surfaces are the most effective pathways in the basin.
The main reservoir rocks in Catatumbo Basin are Cretaceous limestones and sandstones (Uribante Group and Capacho formation) and Cenozoic deltaic sandstones (Barco, Mirador and Carbonera formations). Additionally, fractured basement rocks can constitute potential exploratory targets.
Cretaceous shaly marine rocks and plastic Cenozoic continental claystones constitute the seal units in the basin.
The most important traps correspond to: a) structures related to normal faults with partial inversion; b) structures associated with sub-thrust; c) anticlines produced by strike-slip faulting; d) structures associated to inversion systems (Figure 3). Oil production from Cretaceous rocks is associated with secondary porosity developed by fracturing.
