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Cenozoic Paleogeographic Reconstruction of the Foreland System in Colombia and Implications on the Petroleum Systems of the Llanos Basin

Caballero, Victor M.; Reyes-Harker, Andrés1; Mora, Andrés; and Ruiz, Carlos
1[email protected]

This study shows the implications of the evolution of uplifting areas, sediment sources and depocenters of the eastern Colombian foreland basin system on the timing of hydrocarbon migration.

This work is based on the integration of data from several works developed during the Ecopetrol project "Cronologiacute;a de la deformación en las Cuencas Subandinas" which included new data and studies related with field work mapping of facies and thickness distribution, balanced geological cross sections, paleocurrent measurements, conglomerate and sandstone petrography, biostratigraphy, vitrinite reflectance data as well as the novel dating techniques of Zircon-UPb geochronology, bed rock thermochronology. Data indicating timing of deformation and uplift gathered in previous studies were took into account in this study.

The main results in this work conclude that the Cenozoic evolution of the foreland system includes three stages: a) A compressive phase that uplifted the Central Cordillera and affected the Magdalena Valley and the northern portioins of the Eastern Cordillera, south of the Santander Massif. This phase begins in the Late Cretaceous with a maximum intensity in the late Paleocene and early Eocene; b) A phase of tectonic quiescence of slow deformation rate in the middle Eocene and c) A renewed compressive deformation beginning in the late Eocene lasting until the Oligocene and Miocene.

The paleogeographic reconstruction also shows the variations and location of the sediment provenance domains based on the UPb signal from the Central Cordillera (UPb ages younger than 150 Ma), the evolution and facies distribution along the Magdalena and Llanos basins and the extension, timing of uplift and exhumation of the source areas of sediment. This work allows estimating the precise timing of exhumation of the Eastern Cordillera and this information is fundamental to assess the timing of cessation of oil generation and migration from the kitchens previously located on this range. Equally, this paleogeographic evolution is important to estimate the extension of the kitchen areas at different times and define the extension and configuration of the reservoirs and seals on the Llanos and Magdalena basins. From our assessments it appears that the Oligocene is the most important time for the generation of heavy oils now present in the Llanos basin.

 

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