Petroleum systems in the Rubio and Burgua depressions, Venezuela Article

Callejón, AF, Ostos, M, Yoris, F et al. (2005). Petroleum systems in the Rubio and Burgua depressions, Venezuela .(79), 169-172.

cited authors

  • Callejón, AF; Ostos, M; Yoris, F; Briceño, H; Talukdar, S; Lander, R



  • Hundreds of outcrop samples were analyzed for source rock evaluation. La Luna, Los Cuervos, and Carbonera Formations are considered excellent potential oil sources. However, La Luna and Los Cuervos were the oil-generating units according to 1-D modeling. Therefore, we define La Luna-K/T(!) and Los Cuervos-K/T(!) systems. The study identifies two genetic oil families related to two distinct oil-source rocks from the Upper Cretaceous La Luna/Navay Formations and the Paleocene(?)-middle Eocene Los Cuervos Formation. The interpretation is based on evaluation of source rocks, oil-source rock correlations, oil maturities, and thermal modeling. The integration of the geochemical and geological data, modeling results, and structural interpretation of the area allowed the definition and outline of active kitchens beneath thrust sheets or in deeply buried areas. The results allowed us to map the active oil kitchens present below certain thrusts or thick molassic sediments, and to describe the petroleum systems in the area. La Luna Formation contains good to excellent oil-prone kerogen Type I-II, while Los Cuervos Formation contains gas-oil-prone Type II-III. Numerous oil seeps contain oil that was expelled at the peak of oil generation stage (0.85-0.90% Ro), and which was derived from marine sources. We interpreted this oil to have been generated by the La Luna Formation. We established a geochemical correlation between some oil seeps with the extracted organic matter from Los Cuervos Formation in the Burgua Depression. The analyses indicate a marine algal-bacterial organic-matter source for the Navay and La Luna Formations and a higher plant source for the Los Cuervos Formation. Modeling suggests that maturation was reached during the Andean orogeny, as a result of deposition of thick molasse, and also by tectonic loading. Clastic and carbonate potential reservoirs of Cretaceous (K) and Tertiary (T) age and regional seals of the Colón and León Formations are widespread in the area. Modeling results indicate that migration started during the middle Miocene and is related to Andean tectonic loading. Subsequent migration took place during the late Pliocene, to be blocked by the Capacho and Boconó fault systems.

publication date

  • December 1, 2005

start page

  • 169

end page

  • 172


  • 79