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Hydrocarbon Generation and Charge Models from the Eastern Cordillera to the Llanos Basin: Key Tool in the Quantification of Resources Found in the Llanos Basin and Eastern Foothills

Sanchez, Nelson1; Mora, Andrés; Guzman-Vega, Mario A.; and Garcia, Diego
1[email protected]

We present the results of petroleum systems modelling in the Eastern Cordillera, eastern foothills and Llanos basin. Here we use a petroleum system modeling software as a tool to summarize multiple geological observations after 10 years of studies in the Llanos foothills. The results suggest the presence of two pulses of generation and migration, one of them between 20 and 30 Ma and the other in the last 10 Ma. The first one generated crude oils from the Eastern Cordillera sourced from Upper Cretaceous marine rocks and is responsible for the presence of most of the heavy and biodegraded oils focused in the Southern Llanos Basin. The second, is related to the migration and subsequent trapping of lighter crudes from Upper Cretaceous continental source rocks, located in the foothill kitchens. Oils associated with this second migration pulse are clearly dominant in the central Llanos (Casanare area). However, we cannot rule out Paleozoic or Lower Cretaceous source rocks since this study was focused mostly in the Upper Cretaceous shales. The implications of this model are among others:

-Oligocene reservoirs in the Llanos Basin are optimal for heavy oil traps, if them are associated with traps that were already present at the time of the first migration pulse. Traps of this age dominate in the Southern Llanos.
-The oil expelled during the first pulse is limited by the initial uplift of the kitchens in the Eastern Cordillera.
-Miocene and younger traps in the foothills and Casanare area are dominated by crude oils of the second migration pulse.
-Different oil mixtures from these two pulses have been succesfully predicted and correlate with actual observations.

These results have been useful to prioritize investments in exploration in the Llanos Basin and eastern foothills but also, they correlate well with actual geochemical analysis of crude oils (biomarker and isotopic parameters).


AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013