Seismic analysis of the geological occurrence of gas hydrate in the Colombian Caribbean offshore

• Published in: Journal of South American Earth Sciences
• Main Authors: Rincón-Martínez, Daniel, Ruge, Susy Mercado, Silva Arias, Alejandro
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2022
• Subjects: permafrost
• Online Access: https://oceanrep.geomar.de/id/eprint/57273/; https://oceanrep.geomar.de/id/eprint/57273/1/Rincon-Martinez.pdf; https://doi.org/10.1016/j.jsames.2022.103800

The bottom-simulating reflector (BSR) recognized in seismic sections represents the division between free gas and gas hydrate. This reflector has been identified in the permafrost and several petroliferous marine basins worldwide, including the Colombia offshore basins. Using high quality three-dimensional (3D) seismic data from the Sinú offshore basin (southern Caribbean), the BSR was exceptionally well-imaged within two geomorphological settings, including the Southern Caribbean Deformed Belt and the Colombia Basin, indicating possible gas hydrate presence in the study area. The BSR occurrence was mapped and categorized following existing nomenclature developed off Taiwan into three (3) categories: Basin-type, Ridge-type and Submarine Canyon-type. The BSR occurrence was dominated by the Ridge type category that was mainly found in the accretionary prism within modern and ancient anticlinal structures, followed by the Basin-type BSR found mainly at the Colombia Basin margin and a few intraslope sub-basins. The Submarine Canyon-type was found on small segments of the main drainage routes that cut through anticlinal structures. BSR distribution and characterization was also correlated with a seabed geomorphologic map, including thrusts with bathymetric expression, revealing that the BSR typology map closely resembled the N–S trend of subsurface structures in the south, as well as their NE-SW trend in the central portion of the accretionary prism. We suggest the dimensions (width and depth) of the seafloor features does influence BSR occurrence, tending to parallel major anticlines, and wider/deeper portions of intraslope sub-basins and submarine canyons, while omitting small-scale features.