Archie, Curtis¹
(1) PETROTRIN, Point Fortin, Trinidad and Tobago

ABSTRACT: The Identification Of The Depostional Environments Of The Cruse, Forest And Morne L’Enfer Formations In The Southern Half Of The Gulf Of Paria, Trinidad, West Indies

This study was initiated as part of the examination of remaining exploration prospects in the TRINMAR acreage. Formations penetrated in the area range from Lower Cruse to the Morne L'Enfer Formations .
Five reflectors were mapped through the area, these were the Top Forest, Forest 5, 3 and 1 Tops, Top Cruse and Upper Cruse 4. Sands within the wells were then grouped using the seismic markers, and net sand and oilsand counted for each interval. Interval RMS extractions were done for each interval and then interpreted.
For the Top Forest to Forest 5 interval the RMS showed west – east trending meandering channels, point bar deposits , crevasse splay and beginnings of the flat spot to the north of S255. The Forest 5 – 3 interval also has a number of west – east trending meandering and bifurcating channels. The Forest 3 – 1 interval has NW – SE trending meandering channels. These RMS maps clearly indicate that the Forest was deposited in a lower flood plain setting.
An incised valley in Lower Morne L’Enfer time eroded very strongly into the underlying Forest., between S207 and S255 it trends E – W and then trends NNE – SSW. The result of this erosion is that the subcrop of the Forest gets progressively older to the south (valley axis), toward the shoreline we get older.
In the Upper Cruse , interpretation of the seismic near S. 255 shows a channel complex that is interpreted to be trending WSW – ENE. Lateral migration of sediments within the channel is seen by the dipping reflectors, this is confirmed by the Interval RMS extraction.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004