Barremian - Aptian structural control in the central region offshore Uruguay

Abstract

The structural framework that controls the aptian sedimentation in the distal-central region of Uruguay's offshore basins is identified and mapped in this work. In addition, its relevance from a petroleum perspective is studied. The aptian sequence is a world-class source rock that generated 29% of the world's hydrocarbon reserves, as well as the recent discoveries in Cretaceous reservoirs in Namibia's Orange Basin. As a result, determining the presence and characteristics of the aptian sequence has become critical for any assessment of the petroleum potential in the passive-margin basins of the South Atlantic. Several paleo-restorations show that the Orange Basin and Uruguay offshore basins (Punta del Este, Pelotas, and Oriental del Plata) are conjugated margins generated during West Gondwana fragmentation and the subsequent opening of the Atlantic during the Upper Jurassic-Lower Cretaceous. Along these lines, additional analogies have been developed throughout these basins, resulting in regional aptian sequence deposition on both margins. Although multiple researchers recognize the seismic facies of the aptian sequence on Uruguay's offshore basins, their characteristics are likely different from those deposited in the Orange Basin. This is due to the specific structural controls that allowed the development of a depocenter during Barremian-Aptian times, which contributed to marine restrictions and larger thicknesses of Aptian source rock, both of which have important implications for the generation and accumulation of hydrocarbons offshore Uruguay.