3D resistive characterization of the Paipa geothermal area, Colombia

Abstract

In order to performe the electrical characterization of the geothermal area of Paipa, different campaigns were carried out to acquire audiomagnetotellurics (AMT) and magnetotelluric soundings (MT). The estimation of the apparent resistivity curves is in a period range between 0.0001 and 10 s. The geoelectric dimensionality analysis performed to the impedance tensors established a 1D behavior in low periods and a dominant 2D-3D behavior in high periods. In the light of this, a 3D inversion of the area’s electrical structure was performed using the ModEM code and interpreted under the conceptual model of the geothermal system. The presence of a conductive body was identified in the vicinity of the Alto Los Volcanes and Alto Los Godos domes, where the reservoir location has been previously suggested, and is associated with the possible seal layer of the system. Moreover, a series of conductive bodies in apparent structural control, were observed in the center and NW of the area. These bodies are associated with the transit of fluids to the discharge zones at fault intersections. Finally, a resistive body associated with the basement to the southeast of the area was also identified.