Seismic research restarted at Balmatt geothermal site in Belgium
Drilling rig on site of Balmatt project, Belgium (source: VITO)
Carlo Cariaga
24 Feb 2022
VITO has restarted a research program in the Balmatt geothermal site in Belgium with the goal of understanding the seismological characteristics of the resource.
Belgian research institution VITO have announced the one-year mark since the restart of the research program in the deep geothermal power plant at the Balmatt site in Belgium. Through production and injection testing and using a detailed seismometer network, the goal of the research is to better understand the hydraulic and seismological characteristics of the underground reservoir.
The Balmatt project initially came to a halt following a series of mini-earthquakes caused by the reinjection of pumped water into the drilled wells. We had previously reported that the Board of Directors VITO intended to expand the network of seismometers before coming to a decision on whether the geothermal project will be restarted.
In February 2021, the decision to restart the project was made. The expansion of the seismometer network allowed for more accurate investigation of the causes of induced vibration as well as the possible risks of the vibrations that are perceptible on the surface.
Other upgrades include adding voltage protection to absorb the consequences of a power failure and a pressure maintenance system on the injection well.
Testing procedure
Measurements were made using a total of 16 seismometers positioned at different locations and depths from 30 meters to 2 kilometers. This was necessary to more accurately determine the location quakes, detect lower magnitude vibrations, gain a better understanding of the source mechanisms, and establish a magnitude-frequency relationship.
The first tests took place from 20 April 2021. A maximum injection pressure of approximately 90 bar was achieved, correspoinding to a maximum flow rate of 25 cubic meters per hour. The last and longest test phase started at November 2021 and is still ongoing as of mid-February 2022.
Source: VITO
