"Tectono-Stratigraphic Evolution & Petroleum System of the Eastern Cordillera Foothills and Adjacent Basins (Colomina)"
CENOZOIC TECTONO-STRATIGRAPHIC EVOLUTION AND PETROLEUM SYSTEM OF THE EASTERN CORDILLERA FOOTHILLS AND ADJACENT BASINS (COLOMBIA)
This study was made of an area south of the giant Eocene Mirador Formation Cusiana oil field in the Llanos Foothills of Colombia. A sequence stratigraphic framework (SSF) was built of the complex fluvial to marginal marine sediments of the Cenozoic Formations. Well logs cross sections were constructed using gamma ray well logs normalized to display the sedimentological character and improve the interpretation of cyclicity and depositional settings of well log displays. They established that the channel systems could be defined and mapped within a SSF by tying these to seismic volumes in the frequency domain. This was achieved by applied spectral decomposition to detect the various fluvial systems of the Cenozoic sequence and local the subtle stratigraphic features, both undetectable in time domain seismic data. New gravity, magnetic, well and 3D seismic data provides a better understanding of regional structures and tectonic movement affecting the petroleum system and sedimentary history of an important region of oil production in the Foothills of the Eastern Cordillera of Colombia. To the south the Garzón fault was previously interpreted as a right-lateral strike-slip fault. New seismic, well, and gravity data demonstrate that this fault is also a low-angle (12–17 degrees) Andean fault that thrusts PreCambrian basement 10 to 17 km northwestward over Miocene rocks of the Upper Magdalena Valley (UMV) in a prospective footwall anticline. New geophysical data as well as previous field mapping were used to produce the first gravity and magnetic maps and retrodeformable structural cross section of the northern Garzón Massif. The new model distinguishes for the first time distinct episodes of “thin-skinned” and “thick-skinned” deformation in the Garzón Massif.