Sinopsis De Los Sistemas Petroleros Del Norte De Sudamerica (Venezuela)

This synopsis attempts to outline the most relevant aspects of the tectono-sedimentary settings typifying the northern South American petroleum systems traditionally identified. Also, it will discuss a suite of ideas and evidences to consider the presence of other systems less understood in the region. The traditional systems have been extensively discussed in the literature, where the regional La Luna - Querecual - Naparima Hill System, conformed by the Cretaceous (Turonian) source beds and the Aptian sequence from Western Venezuela, is the most popular and better studied. Superposed to the Cretaceous, we find an effective source beds assemblage from the Lower Tertiary System (Paleogene) in the Maracaibo Basin. Another system developed from a suite of source rocks of Oligocene - Lower Miocene age, with a good generation potential is found next to the Caribbean folded belt front along the Central region of the country. Further East up to the limits of the Orinoco Delta there is an active kitchen coupled with younger source bed sequences from the Neogene. Straddling on top of the Caribbean Ranges there is a series of confined petroleum systems. Their ages extend throughout the Oligocene on the west up to the present towards the Northeastern end. Locally, these isolated systems could include source beds from the Cretaceous. The mass balance results from the Maracaibo Basin studies showed an acceptable match between hydrocarbons generated and the trapped volumes (similar order of magnitude). Whereas, the different estimates from the Eastern Venezuela Basin for the same type of analysis reflect major discrepancies when considering the Faja PetrolIfera del Orinoco volumes. These volumes are very difficult to reconcile with the data available from<br>the traditional systems, even if we do not include the effect of crude biodegradation. This fact forced a review of all the concepts on source beds, migration path, and preservation scheme for any other potential source bed candidates hosted in the pre-Cretaceous sedimentary package. The second group of petroleum systems highlighted in this overview belongs to the pre-Cretaceous family.