Geophysical Studies to Detect a Favourable Location for a Thermal Water Well

Several geophysical surveys were carried out in order to determine the best location for a new production well for the spa of Caldas de Monção, in order to increase production of thermal waters due to an increasing demand of the facilities. After a dipole-dipole survey conducted in 2001 that reached a depth of investigation of about 40 m and 2 shallow wells, three seismic reflection profiles were acquired to locate deep rooted faults capable of groundwater transport to the surface. Vertical electrical soundings and the refraction interpretation of the first arrivals of the reflection data were also undertaken to complement the information. This paper presents the integrated interpretation of geophysical and geological data in order to achieve the above mentioned goal. After the interpretation and lateral correlation of the structures found in the geophysical profiles, two locations appear as the strongest candidates for a successful thermal water production well. This example shows the utility of geophysical methods in detecting favorable areas for water borehole drilling, reducing economical costs considerably.