Modeling of Bouillante geothermal field (Guadeloupe, French Lesser Antilles)
Résumé
With a 15MWe capacity the Bouillante geothermal plant can supply the Guadeloupe Island (French Lesser Antilles) with 6 to 8% of its annual consumption of electric energy. New exploration projects are currently considered to expand this production capacity. Several simple models have been developed to support optimal development of the geothermal field and its management especially as reinjection of the cooled brine started recently. Lumped parameters models were used as first exploration tools to test conceptual schemes of the geothermal field. They were successfully used to forecast pressure evolutions and link production flow rates with reservoir pressure as inferred from wellhead pressure. As a first step towards a more general understanding, all available data is being gathered to build a conceptual geological and hydrogeological model integrating both regional and reservoir scale data. Current efforts are focusing on the development of regional scale hydrothermal modeling to help exploration activities. Numerical developments are still necessary to model the whole hydrothermal system over a large range of thermodynamical conditions (Copol et al., this conference). At reservoir scale, we are using the Tough2 geothermal reservoir simulator to test different hypothesis. Despite the relative scarcity of data concerning the reservoir state, the impact of fracturation on the reservoir behavior has been considered and well pressure interferences data have been successfully reproduced using the MINC concept. Yet, the need to use excessively high fluid compressibility to fit available data could be explained by a possible two phase zone somewhere in or around the reservoir. This hypothesis still remains to be tested. Our goal is to use complex meshes derived from the geological model built from observation and seismic data. Thus we'll try to identify which are the main phenomena that control reservoir behavior.