Geophysical and Geological Evidences of a Petroleum System of Gas Hydrates in the Colombian Caribbean Sea

Calle, Andres E.

Several researchers have been done estimating the potential of gas hydrates in the Colombian Caribbean sea, Lopez and Ojeda 2006, Gomez & Leon 2001, and Krason 1984, however, after carefully reviewing the state of the art of national and international programs as The Gulf of Mexico Gas Hydrates JIP, MH21, Canada, South Korea, China among others, unfortunately, it easy to conclude that Caribbean estimates lack of key concepts that support them. Concepts related to the petroleum system of gas hydrates, risk analysis or geohazard issues, and the stability zone have not been addressed. In contrast, in the above programs, many paradigms have been broken, such as the need for BSR as an indicator of the presence of hydrates, the hydrate distribution within the stability zone, which could be related with the type of reservoir rocks, etc.

Aiming to increase the knowledge on the natural behavior of gas hydrate reservoirs in the Caribbean, a project was planned to reduce the uncertainty in the analysis of gas hydrates potential. The first step was to maximize the use of the current information and plan future activities, this work in particular treats some of the foundings in the first step. We filter the current information in the Caribbean, mainly 3-D seismic, and then, several pilot areas were chosen with basic indicators of gas hydrates. These are presence of BSR, blanking zones, high amplitudes as well as attenuations, gas migration pathways, changes in polarity at the boundary of the stability zone, and, seismic geoforms, most likely turbidites, acting as feasible reservoirs.

As a result, five pilot areas were identified and clearly delineated, all of them located in 3-D seismic volumes and within the theoretical stability zone, this zone was estimated between 500m and 3000m water column depth, being offshore boundaries, other boundaries are the exclusive economic Colombia zone. In these five areas were collected evidences of potential petroleum system in gas hydrates, as migration routes (faults, volcanoes and gas chimneys), a possible model for gas supply by the presence of an accretion system, Hydman 1991, BSR distribution similar to other basins, Thakur & Rajput 2011, and sand bodies. This information is being used to design an oceanographic data acquisition with piston core, heat flow, among other geophysical data, in order to find more evidences and estimate the potential in siliciclastic reservoirs in the Caribbean Sea.

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