Use of Balanced Structural Sections to Improve Definition of Complexly Deformed Reservoirs in the Eastern Foothills of the Cordillera Oriental, Colombia

Abstract

The Cordillera Oriental of Colombia is a thick-skinned thrust-belt produced by Oligocene-recent inversion of a Jurassic-early Cretaceous rift followed by post-rift thermal subsidence and deposition of a Cretaceous marine sedimentary sequence. In the eastern foothills of the Cordillera Oriental thrust deformation transitions from a thick-skinned style to the thin-skinned style characterized by antiformal stack duplex overlying other thrust sheets. The formation of thrust-related structural traps, pulses of uplift and exhumation of the foothills thrust-belt over a period of 30 Ma is important to understand a known petroleum system with known discoveries since 1990's totaling 1083 MBOE. Four balanced cross section illustrate the deformation of the Cretaceous Guadalupe formation, Paleocene Barco Formation and Eocene Mirador formation reservoir rocks at the Pauto, Florena and Huron producing fields. Along the southern areas through the Pauto and Volcanera fields, the south-dipping thrust faults have larger throws (4.8 km) but less folding and fewer thrust sheets. To the north thrust deformation increase with the appearance of more thrust sheets (50% of shortening) with less displacement on major faults (Yopal and Guaicaramo thrust faults). Axial planes of the Nunchia syncline and Monterralo anticline plunge southward showing that the basal detachment of the Nunchia syncline shallows in the north with many underlying thrust sheets which are all prospective traps and seals for hydrocarbons. Areas of likely reservoirs will less risk are proposed using the cross sections and its sequence of deformation.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015