Subsurface Structure, Stratigraphy and Hydrocarbons of the Falcon Basin: An Inverted, Hydrocarbon-bearing Rift Basin in Western Venezuela
Blanco, Joan M.1; Mann, Paul; and Bartok, Peter
The surface geology of the Falcon basin (FB) of western Venezuela has been intensively studied since the early studies of Senn, Kugler and Renz in the 1930s and 40s. In this presentation we use 2000 km of 2D seismic data, 1130 km² of 3D seismic data, and 65 correlated wells within the basin and on its northern flank to define its regional stratigraphic and structural history. This history provides many useful insights and analogs for ongoing exploration to the northwest in the Gulf of Venezuela and to the east in the deepwater Bonaire basin. The main structures of the FB consist of: 1) a well imaged, northern border thrust dipping NE; 2) an anticlinorium of basin fill with ENE-WSW vergence and ranging in age from middle to late Miocene with fold axes trending east - northeast and wavelengths of 5 to 12 km; 3) northeastern border thrusts in the eastern offshore basin in the transition area to the Bonaire basin; and 4) a southern boundary thrust that is not covered by the seismic data used in this study. Wedging along subsurface stratigraphic units seen on seismic and in wells show that the main phase of NS extension occurred along EW-striking normal faults from Eocene to Oligocene and NS shortening and normal fault inversion began in the Late Miocene and extends up to the present day. The timing of extension (Late Oligocene – Early Miocene) is younger than observed in the offshore Bonaire basin (Paleogene) and may be related to a slab rollback effect following the emplacement of the Lara nappes to the south. Marine source rocks of Oligocene-Miocene age are present across the basin and appear to have matured during deep burial in early Miocene time; reservoirs are mainly well sorted, coastal sands now deformed into tilted antinclines formed during Late Miocene to recent fault inversion. For 2000, the official production of the basin was 375 MMBO of mainly light oil. While the earlier extensional history of the FB is shared with the Gulf of Venezuela and Bonaire basin, the late inversion history of the FB appears localized as a result of NS shortening of the basin between the northward-moving Maracaibo block and the Paraguaná basement block of NW Venezuela.
AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013