Magnetotellurics (MT) provides images of the low resistivity alteration characteristic of hydrothermal alteration usually associated with an active upflow. The accuracy of the resistivity images is therefore an important factor in the definition of the conceptual model. The sensitivity of MT decreases with depth.
To improve the geophysical image, we test joint and constrained inversion of MT, gravity and seismic ANT data in context of conventional and unconventional geothermal reservoirs.
Joint inversion needs to couple parameters of different nature, here resistivity density, velocity. We developed various types of coupling techniques based on gradient and parameter correlations in addition to the now classical cross-gradient.
I shall present some results in Caribbean, Eastern Africa and continental France.