Use of the Digital Elevation Model for Offshore Hydrocarbons Exploration

Abstract

It is exemplified, in the Block L of the Central East-North Cuba Sector (Cuba–Bahamas–Haiti Exclusive Economic Zone), the use of a Digital Elevation Model (DEM) at 90 × 90 m resolution for the detection of subtle positive geomorphic anomalies possibly related to hydrocarbon microseepage (vertical migration) on oil and gas targets. DEM data are integrated with geological, seismic, and Induced Polarization (IP) information. The results support the conclusion that DEM data provide a lower cost and fast offshore oil and gas preliminary exploration strategy. These data are useful serving to focus prospective areas to be checked with supplementary unconventional methods such as magnetic and IP and, after that, to propose the more expensive volumes for detailed 2D–3D seismic survey. In the particular case of Block L, the most intense geomorphic epicenter (geometric center of a geomorphic anomaly) does not coincide with a local dome of any Upper Jurassic horizons (presumably reservoirs), suggesting a possible link to a “Gas Chimney,” related to a tectonic knot (local converging area of several tectonic dislocations) inside the North Cayo Fragoso structure. This hypothesis would also explain the observed intense IP anomaly. A “Gas Chimney” seems to be confirmed by 2D seismic information, for which the vertical zones of light hydrocarbon seepage are evident as well as their exit to the oceanic bed in the form of small podmarks.