Print this pageSuriname Offshore — The Not-So-Passive Margin?
The Suriname offshore area is traditionally considered to represent a passive margin during its development. More and more however, it becomes evident that tectonics plays an important role in the entrapment of hydrocarbons, on a minor as well as on a major scale.
This is now evident in the Tambaredjo and Calcutta onshore fields, where minor faults significantly contribute in the trapping of the hydrocarbons, in a setting that was previously thought to be purely stratigraphic in nature.
The main tectonic phase occurs in the Early Cretaceous, when the opening of the South Atlantic and associated rotation of the African Continent resulted in significant compression and folding of mainly Jurassic syn-rift sediments in the North Atlantic Basin.
The major expression is the uplift of the highly folded and faulted Demerara High area, and the subsequent erosion of large amounts of Early Cretaceous sediments. The Demerara High is surrounded by a number of sub-basins, still unexplored, but containing potential for both fault trapping and sealing of dipping strata by the Lower Cretaceous unconformity.
A younger, Tertiary, tectonic phase is related to the edge effect of the Caribbean Plate that is continuously moving to the East. The effects can be observed in the Suriname part of the Guyana basin as a series of strike-slip faults parallel to the coast that could create structural closures to basin-ward dipping reservoirs along the sand rich shelf edge.
This new finding, in addition to the widespread presence of the prolific Upper Cretaceous, La Luna analogue source rock in this basin, increases the prospectivity of the Suriname offshore area.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil