Stratigraphic Traps of Turbidite Fields in Campos Basin, Brazil
Ricardo Defeo de Castro
Exploration Manager, Campos Basin, Petrobras
The Oligomiocene Turbidite Complex of Campos Basin presents several good examples of oil fields controlled by traps with stratigraphic components. Among those, the main examples are the fields of Marlim, Albacora, Caratinga, Barracuda and Voador, all of these located in the deep water context.
This Oligomiocene Turbidite Complex reveals a great magnitude, spreading out sand sheets over an area around 5000 km². The importance of this complex is so expressive that it used to represent more than half of the total oil reserves in Brazil before the big discovery of the pre-salt carbonate giant fields in Santos Basin. This Deep Water Complex is composed of an extensive coalescence of several Channel-Lobe Systems, deposited from intra-slope basins, controlled by salt movements, up to open fans in basin floor settings. Some of these systems were partially dissected by superimposed erosional channels during progressive sea level fall, with a tendency for a successive migration of the depositional equilibrium point basinward, which had built a general deep water prograding complex, with a backstepping stacking pattern occuring inside each particular system. The erosional processes were responsible for modeling isolated residual sand bodies resulting in paleogeomorphic traps.
Besides the erosional events that resulted in paleogeomorphic traps, other main control for the existence of the stratigraphic traps observed in the Campos Basin is the sand pinching out up-dip due to the process of sediment bypass and steep slope non-deposition, avoiding the oil leaking slope upward. In a few cases, differential compaction also plays a role for oil entrapment.
AAPG Search and Discovery Article #90204 © AAPG Geoscience Technology Workshop, Stratigraphic Traps and Play Concepts in Deepwater Settings, May 14-15, 2014, Rio de Janeiro, Brazil