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New Geologic and Geophysical Constraints in the Assessment of Exploration Plays in the Lower Magdalena Basin, Onshore Northern Colombia

De Freitas, Mario G.1; Mora, Alejandro; Mesa, Andres M.; Velez, Vickye; Martinez, Monica; Sierra, Daniel; and Serna, Lina
1[email protected]

The Lower Magdalena Valley (LMV) of northern Colombia records a complex tectonostratigraphic development since the Late Cretaceous. The uncertainties associated with the multi-phase geologic history led to limited exploration success in over a century, with approximately 0.5 bboe discovered. Our regional assessment suggests a significant unrealized potential.

Critical geologic uncertainties remain associated with all known and inferred exploration plays in the LMV. Common to all plays is the poorly constrained burial history and scarce geochemical characterization of potential source rocks. We present advances in the understanding of the LMV exploration plays based on the evaluation of a comprehensive regional database comprising 2D, 3D seismic, gravity-magnetics, well logs, biostratigraphic, petrophysical, geochemical, AFT data and surface geology.

The main LMV exploration plays are examined in terms of reservoir age and type, with trap styles defining sub-plays. The bulk of commercial discoveries to date are associated with (i) the Late Oligocene ("Cienaga de Oro") sandstone and (ii) the Early Miocene ("Cicuco") limestone plays, mostly in structural traps along the eastern LMV. Reservoir distribution is the critical risk of these plays. New geologic and geophysical constraints leading to new stratigraphic discoveries in the Cienaga de Oro play are examined, as well as evidences for a much broader occurrence of the Cicuco play.

Along the San Jacinto foldbelt, western LMV, a series of poorly understood plays are collectively referred to as the pre-Oligocene plays. The distribution, quality and timing of maturation of upper Cretaceous and Paleogene source rocks, as well as migration pathways in a strongly inverted area, are critical uncertainties of these plays. Distribution of the potential Eocene and Paleocene limestone and clastic reservoirs is also poorly understood. Nevertheless, these plays have a significant potential, as indicated by numerous surface seeps and shows in wells. New geologic and geophysical data help constrain these uncertainties.

A significant potential is also anticipated in the Mid Miocene ("Lower Porquero’) play along the eastern and central LMV. Deep water deposits derived from the east and south and partly fed through large canyons are the primary target for this mostly underexplored play. Regional seismic mapping highlights the most prolific areas.

 

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