Geothermal Case studies

ETI has been involved in geothermal projects in many countries, either directly or through the use of our equipment, including Chile, China, Germany, Greece, Hungary, Iceland, Malaysia, Mexico, Saudi Arabia, Slovenia, Thailand, and the USA.

Here, we are showing some selected summaries.

Exploring for geothermal resources in Hungary

In Hungary, we were tasked to define geothermal exploration targets where the leases were available. We carried out a multiphysics acquisition program and integrated interpretation, including geoscientific a priori information (geology, well logs, seismic, and others). The details can be found in Tulinius et al. (2008). We combined the geologic interpretation with the vintage seismic data and used that as a starting point for the interpretation, as shown below.

We carried out gravity and magnetotelluric acquisition, leading to a two-dimensional inversion, first independently and then combined. In the figure below, we are showing a resulting target where a density anomaly coincided with a resistivity anomaly. A low density means higher porosity and fluids, and low resistivity means higher temperatures. Since this is a hydrothermal target in a sedimentary basin, we are expecting increased-temperature water. Drilling targets were selected accordingly and verified by three-dimensional modeling/inversion. The drilling location in the seismic section in the subsequent figure. The well confirmed the interpretation and resulted in a 4.2 MW geothermal power well test.

In SW Saudi Arabia, we supported our client in doing multiphysics data acquisition in the Ain Al-Harrah area. The area has a hot spring, and as a result of the interpretation, we defined the flow cell shown below. Details can be found in Ashadi et al., 2023, 2024.

The following image shows the survey layout, on the right, and the resistivity section on the left. The two-dimensional image shows the flow cell; a three-dimensional inversion rendition is shown in the subsequent figure, which gives a better view of a potentially large geothermal body.

For producing geothermal reservoirs in the USA, we carried out a three-dimensional feasibility and noise test (ETI's proprietary workflow) to see if electromagnetics can define cooling spots in the three-dimensional geothermal reservoir.

In the following figure, our workflow is shown on the top left, with a picture of the field test below. The noise test resulted in noise spectra, which are superimposed over three-dimensional modeling (measured voltages) results for different receiver-to-transmitter distances (bottom right).

To define the best sensor for a potential survey, we are comparing the three-dimensional responses for a hot and cool reservoir in the top-right figure. Since we can see the differences between the cool (solid lines) and hot (dotted lines) we conclude that CSEM can map the production-related cooling zones.

How ETI de-risks geothermal development

• Converts early-stage uncertainty into drillable, bankable targets
• Uses multi-physics acquisition + rigorous inversion to improve subsurface confidence
• Integrates results with geology, seismic, and well data for decision-ready interpretation
• Reduces risk by clarifying temperature, permeability, and flow pathways
• Supports the full lifecycle: targeting → well placement → production monitoring