Thermal history and implications for evaluation of the exploration risk in the Catatumbo Basin

Thermal and geochemical data are discussed to make inferences about exploration risk in the Catatumbo Basin. In this basin is outstanding the presence of prolific source rocks (Capacho and the La Luna Formation), as well as the ubiquitous presence of solid bitumen and oil and gas production with a broad range of API gravity. The thermal data of different sources indicates within the basin, processes of generation and migration continue for a long time, suggesting a low exploration risk regarding charge and synchronism. The hydrocarbon expulsion time from Cretaceous source rocks (Capacho and La Luna formations) started in the Late Paleocene-Eocene, while for the Tertiary unit, the Los Cuervos Formation, the generation and expulsion started at 10 my. The petroleum expelled during the Paleocene-Miocene, were accumulated in structures formed since the end of the Cretaceous age, while structures associated to the Andean orogeny were charged by remigration and additionally with younger hydrocarbons generated from the less uplifted areas related to actual synclines axes. Thermal maturity data of rocks, oils and gases show petroleum of different maturity stages, the more mature accumulated in cretaceous rocks, while the less mature were trapped in tertiary reservoirs. Regarding exploration risk, the southern portion of the basin looks more thermally evolved and prospective for wet and dry gas while the central and northern area appears more prospective and for wet gas, light and normal oil.