--> Abstract: Modelling and Geochemical Characterization of Organic Facies in the Upper Cretaceous Chipaque Formation, Eastern Cordillera and Llanos Foothills, Colombia, by Blanco-Velandia, Vladimir O.; Felix, Maarten; Wagner, Thomas; Campiño, Luisa; Parra, Carlos; and Plata, Angelo; #90166 (2013)

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Modelling and Geochemical Characterization of Organic Facies in the Upper Cretaceous Chipaque Formation, Eastern Cordillera and Llanos Foothills, Colombia

Blanco-Velandia, Vladimir O.1; Felix, Maarten; Wagner, Thomas; Campiño, Luisa; Parra, Carlos; and Plata, Angelo
1[email protected]

Field observations, bulk geochemical data-sets, palynofacies analysis, and 1D-organic facies modelling were collectively utilized to depict vertical and lateral distributions of organic facies in Cenomanian-Santonian strata of the Colombian Eastern Cordillera (EC). The sediments analysed correspond to dark fine-grained lithologies exposed in two outcropping successions of the Chipaque Formation on the Eastern flank and toward the axial zone of the EC respectively. Source rock screening indicates highly variable petroleum generative potential with hydrogen index values ranging between 13 and 528 mg hydrocarbon (HC)/g total organic carbon and immature to marginally mature sediments for oil generation at both locations. Mean vitrinite reflectance values (%Ro) between 0.39 and 0.55 were found to be consistent with pyrolysis Tmax data in the range of 400 to 435°C . Further characterization of organic matter via palynofacies analysis was employed to identify, quantify and assess the level of preservation of particulate organic components in kerogen and therefore, to provide insights on determining aspects such as, depositional conditions and source-rock potential. Organofacies modelling using OFMod-1D was applied to quantify relative concentrations of marine, terrestrial and residual organic carbon fractions and four organic facies were defined: AB, B, BC and C (sensu Jones, 1987). The present organic facies models have implications for palaeoenvironmental reconstructions and exploration risk assessment within the eastern flank of the EC, since it provides a comprehensive characterization of sedimentary organic matter and demonstrates the occurrence of excellent source rock potential within the two sites under investigation. GC and GC-MS data sets indicate geochemical similarity between extracts of the studied sediments and a representative set of crude-oil samples from the Llanos region. Such a positive correlation implies possible contribution of different organofacies of the Chipaque source rocks to the petroleum charge in the Llanos Basin.

 

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