Geophysical Methods Applied to the Assessment of the Bouillante Geothermal Field (Guadeloupe, French West Indies)

Hubert Fabriol (1) , Adnand Bitri (1) , Bernard Bourgeois (1) , Nicole Debeglia (1) , Albert Genter (1) , Pol Guennoc (1) , Philippe Jousset (1) , Jean-Marc Miehe (1) , Jean-Yves Roig (1) , Isabelle Thinon (1) , Hervé Traineau (2) , Bernard Sanjuan (1) , Catherine Truffert (1)

1 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)
2 CFG - Compagnie Française de Géothermie

The geothermal field of Bouillante is located on the west coast of the Island of Guadeloupe in the Lesser Antilles. It has been explored in the beginning of the 70's and was producing 4 MWe until 2003 from a single well, BO2. Production increased up to 15 MWe in 2004, with two new wells, BO5 and BO6, drilled 500 m south-east of BO2. The producing zone is located along the EW Cocagne Fault, intersected by these three wells at different depths between 300 and 1000 m. Production and tracer tests and geochemical results show that the reservoir is of large extension and connected to the sea. Geological reconnaissance and the existence of hydrothermal springs along the seashore and off shore in the Bay of Bouillante suggest that other geothermal resources possibly exist in the northern part of the bay. Different geophysical methods have been applied in 2001, 2003 and 2004 in order 1) to constrain the conceptual model of the known geothermal field and 2) to locate this hypothetical reservoir: 2-D electrical imaging survey, bathymetry mapping, off shore high resolution seismics, off shore and on shore magnetic survey. Geological, thermal and production data from existing wells have been used to constrain geophysical interpretation. Electric imaging has been performed using a dipole-dipole array along an 6-km long profile, parallel to the coast. The interpretation outlines faults and conductive zones which are interpreted as either productive or intensely hydrothermally altered zones. High resolution marine seismic data have been acquired along the shore with a 6-channel streamer and a 1000 J sparker source. Faults are pointed out and related to faults mapped inland. The offshore magnetic survey detects anomalies which correlates, from one part, with those faults and, on the other part, with volcanic cones that appear on the bathymetric map of the bay. Magnetic measurements inland help to link the structures detected offshore to the geological structures inland.

Mots clés: geothermal exploration; Guadeloupe Island; geophysics; electrical imaging; high resolution seismics; magnetic survey.; magnetic survey

Domaines: Géochimie; Milieux et Changements globaux

Hubert Fabriol, Adnand Bitri, Bernard Bourgeois, Nicole Debeglia, Albert Genter, et al.. Geophysical Methods Applied to the Assessment of the Bouillante Geothermal Field (Guadeloupe, French West Indies). World Geothermal Congress 2005, Apr 2005, Antalaya, Turkey. 6 p. ⟨hal-00768756⟩