Seismic Geomorphology of a Shelf-Slope System in the South of Colombian Caribbean Offshore Based on Seismic Attributes Analysis

Alfaro, Esteban; Ramírez C., Víctor O.; Malagón, Fabio; Olaya, Iván

A geomorphological interpretation supported by the application of seismic attributes was fundamental to recognize the distribution, geometry and evolution of marine depositional elements in Colombian Caribbean offshore. Diverse stratigraphic and geomorphological features of south Colombian Caribbean basin were interpreted directly from three-dimensional seismic data using semblance and RMS amplitude extraction. A set of thick channel-levees, incised channels, incised channel fills, mass transport deposits and sheet sands were identified. Different depositional geometries as lobate, amalgamated, confined, semiconfined, tabular, lineal and curvilinear were identified. Depositional elements were related to a high gradient slope and diapirism. Mass transport processes have been dominating continuously the south Colombian Caribbean basin since Late Pliocene until present. Lobate confined sheet sands, lobate mass transport complexes and curvilinear channel-levees were deposited in the northernmost zone of a middle-lower slope system during Late Pliocene. Increasing of lobate mass transport complexes and decreasing of confined sheet sands occurred in a middle shelf to lower slope system during Late Pleistocene. Deposition of lineal incised channel fills and formation of highly lineal incised channels and thicker lobate mass transport deposits occurred in an inner shelf to lower slope system during Holocene. Thicker sheets sands and channel-levees with high lateral continuity could represent good hydrocarbon reservoirs. Meanwhile, thicker mass transport deposits with high lateral continuity could be an excellent seal. Decreasing of sheet sands and increasing of lobate mass transport complexes and incised channels should be related to a relative sea level falling and consequently reducing of accommodation space since Late Pliocene to present. This process explains the increasing in sedimentation of proximal facies during Pleistocene and Holocene. Seismic geomorphology analysis using seismic attributes provide a fundamental tool to understand and interpret the evolution, distribution and lateral geometry of different rock bodies that can be elements of the hydrocarbon system.

AAPG Search and Discovery Article #90163©2013AAPG 2013 Annual Convention and Exhibition, Pittsburgh, Pennsylvania, May 19-22, 2013