Imaging the Kemaliye geothermal reservoir using three-dimensional magnetotelluric inversion with full distortion correction

Abstract:

The Gediz Graben in western Anatolia is a well studied tectonic feature and an area of ongoing exploration for geothermal energy. The target of exploration are typically fault damage zones associated with graben bounding normal faults that allow the migration of hot fluids. Within the Kemaliye concession, located at the northern margin of the Gediz Graben, more than 300 MT/AMT stations were acquired in order to image the geometry of the basement and infer the location of major faults. In addition, time-domain electromagnetic (TDEM) measurements were acquired at each site to be able to correct for static-shift.

We present 3D inversion results for this dataset using a novel inversion technique that simultaneously inverts for a conductivity model and the four parameters of the full distortion matrix at each site. Using this approach results in a better recovery of structures and less artefacts for the near-surface compared to inversion without any correction. We will demonstrate how this approach works in practice and compare the recovered distortion parameters with the static-shift correction inferred from the TDEM measurements. A comparison with recently drilled boreholes in the area allows us to further verify the accuracy of our inversion results.