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By Samarjit Chakraborty, Ewing-Worzel Fellowship.

Abstract:
The project titled "Stratigraphy, Structure and Depositional Processes Offshore Eastern Trinidad and Venezuela" on which I am presently working integrates existing 3D industry seismic data in order to characterize the Late Pleistocene and Holocene sediments. The 3D volumes analyzed are located straddle the shelf-slope transition of the Columbus basin. Post-Eocene eastward Carribean plate motion along the northern margin of South American plate from has produced a northern area of E-NE-trending, elongate basins controlled mainly by strike-slip faults and a southern area of NW-trending, elongate basins controlled mainly be normal, growth faults. In the 3D volumes of the Columbus basin presented in this talk, the normal growth fault style is dominant and has controlled the regional and local distribution of fluvio-deltaic sediments deposited from the proto-Orinoco River drainage system. I analyzed the upper 1000 milliseconds of 3D seismic data made available to this study. The post stack time-migrated 3D data sets provide detailed images of shale diapir geometry, fault orientation and seismic facies. These surface and near-surface features are illustrated in map view and cross section using high-resolution bathymetric and horizon maps. The vertical section interpretation along with map patterns and well and bottom core data forms the basis for interpreting the main architectural elements (e.g., channel complexes, hemi-pelagic drapes, etc.) that form the sedimentary sequences. The dimensions of these architectural elements form the basis for predictions about the facies types and dimensions of potential reservoirs deeper in the basin.