Timing of hydrocarbon entrapment in the Eastern Foothills of the Eastern Cordillera of Colombia
The Eastern Foothills in the Eastern Cordillera of Colombia have been an important oil producing region since the discovery of the Cupiagua and Cusiana fields. Several organic rich Cretaceous-Paleogene units have been considered to be the principal source rocks. The Aptian Fomeque Formation and the Cenomanian-Coniacian Chipaque Formation and the Paleocene Los Cuervos Formation. We modeled the petroleum systems of these three source units to characterize the hydrocarbon generation and accumulation processes within the basin. We found that the maturation history of the system was largely influenced by changes in crustal deformation produced during the tectonic evolution of the Colombian Andes. The Aptian Fomeque Formation. reached the oil window during the Paleocene in the south and the Eocene in the north. The Cenomanian-Coniacian Chipaque Formation reached the oil window in the south by the Early Oligocene and in the north by the Late Oligocene. In contrast, the Paleocene Los Cuervos Formation entered the oil generation window by the end of the Oligocene in both the North and South areas. Our model suggests that the charge history of the main reservoirs has a diverse history also. The shallow marine Albian sandstones were charged during Oligocene to Miocene. In contrast, the proven reservoirs in the area (including the Upper Cretaceous shallow marine reservoirs, the Paleocene fluvial reservoirs and the Eocene fluvial-estuarine reservoirs) were filled by the end of the Miocene, with a second episode of recent (and perhaps active) filling of the Eocene reservoirs from the Paleocene source rocks.The results suggest that petroleum systems modeling is useful not only to predict and characterize generation and migration processes, but also provides insights into the origin and evolution of present-day subsurface structures and the distribution of oil reservoirs in structurally complex areas such as the Colombian foothills.