Coupling of the 3D geologic modelling and the hydro-thermal modelling: contribution in the understanding of the geothermal system of Lamentin (Martinique)

Geothermal energy has become one of the recognized processes to supply energy and to stop significantly the emission of greenhouse effect gases in the atmosphere. This classical renewable energy consists to extract thermal energy into the Earth and to produce heat, cooling and/or electricity. But particularly for the last case, only a few places in the world can exploit it. Indeed, the geothermal reservoir must be permeable and easily accessible. The subduction setting of the Lesser Antilles is favorable to the presence of geothermal reservoirs but its insularity and its volcanic nature have a negative impact on the exploration phases. The influence of the sea on electromagnetic methods, dense bush and the strong urban development add other obstacles. Thus, the risk of failure increases. Consequently, the localization and the characterization of the geothermal reservoir must be more precise. Facing these many constraints, it is essential to apply adapted methodologies and to build the best conceptual model as possible. The coupling of numerical models is presented and applied to the low enthalpy geothermal system of Lamentin, in Martinique. This approach could be developed for other countries with the same geodynamic context. The Geomodeller software and the ComPASS Code are the two numerical tools which have been employed to generate a 3D geological model then to simulate the hydrothermal aspect. The building of the 3D model gives elements of knowledge and thinking about the geothermal system of Lamentin and the hydrothermal simulations suggest some hypothesis on the localization and the intensity of the heat source. (author)