Petrophysical properties of volcanic rocks and impacts of hydrothermal alteration in the Guadeloupe Archipelago (West Indies)

The results of the GEOTREF project presented here aim to develop high enthalpy geothermal energy in fractured reservoirs. They focus on active volcanic islands, especially the Basse-Terre Island (Guadeloupe Archipelago). As part of this project we measured several petrophysical properties to better understand how fluids flow in the hydrothermal system, provide a set of parameters to modelers and build datasets for future interpretation of well logs. The thermo-physical rock properties of bulk and grain density, porosity, permeability, compressional wave velocity, thermal conductivity and diffusivity, specific heat capacity of outcropping volcanic rocks from the Guadeloupe Archipelago (Lesser Antilles) were measured and a dataset was built. According to field observations, samples were grouped into three lithological classes and then separated by their degree of alteration according to macroscopic aspects and optical microscopy results. Geochemical data were obtained, and magnetic minerals identified by combining anisotropy of magnetic susceptibility and variation of magnetic susceptibility with temperature.