ИСТИНА

The paper presents a review of recent advances in using of electrical resistivity as a proxy parameter for indirect estimation of reservoir properties in geothermal areas. Deep temperature model built in the Soultz-sous-Forêts (France) from profile magnetotelluric data and temperature well logs allowed locating heat sources and detecting the boundary between convection-conduction zones. It was also used for constraining the location of a new exploration well so that to reach sufficiently high temperatures at minimal depths. 3D temperature model of the Hengill (Iceland) geothermal area up to the depth 20km was built. Joint analysis of 3D resistivity and temperature models taking into account gravity anomalies enabled to suggest a new conceptual model, which, in particular, explains appearance of extremely high temperatures at shallow depths. Joint analysis of the temperature and electrical resistivity models of the Larderello-Travale (Italy) geothermal system up to a depth of 10km suggests that the heat transfer is carried out by supercritical vapor-gas fluids rather than by liquid ones, as it was concluded based only on the electrical resistivity model. Benefits of a new drilling strategy (“Forecasting-While-Drilling”) based on using of logging and electromagnetic sounding data for predicting reservoir properties at large depths during drilling are demonstrated.