Cenozoic Petroleum Systems of the Sinú – San Jacinto Basin. Exploratory Perspectives of a Promising Frontier

The Sinú San Jacinto Basin (SSJ) although the abundance of oil and gas seeps, is an under-explored and poorly understood basin, especially on the dynamics of the petroleum systems. A long lasting exploratory paradigm about the basin is the absence of source rocks for liquid hydrocarbons in the Cenozoic sequence and that the oil found in wells and seeps has provenance from upper Cretaceous rocks (Cansona Fm.). However, recent studies of source rock quality show that in the Cenozoic sedimentary succession, particularly of Paleocene age, there are intervals with source rock characteristics appropriate for generation of liquid hydrocarbons, which is corroborated by detailed studies of biomarkers from rock extracts, crude oils and seeps in the basin, suggesting that the input of hydrocarbons sourced from units deposited during the Cenozoic is more important than previously believed for the basin, being probably the most important source. Similarly generation models of some depocenters, calibrated with thermal maturity data (Tmax and% Ro) and biomarkers, indicate that the Cenozoic sequence, especially Paleogene rocks, can reach maturity conditions suitable for hydrocarbons generation similar to those estimated from biomarkers from crude oils in the basin. These results open a new spectrum of exploration opportunities in conventional and unconventional petroleum systems associated with the Cenozoic, increasing the prospectivity potential of this under-explored basin.