From seismic to heat in two years
Innargi
Aarhus and Copenhagen, Denmark
Urban City Centre
RealTimeSeismic (RTS)
Geo Subsurface Experts
STRYDE Nimble Seismic System
Innargi is developing two large-scale geothermal projects, one in central Aarhus and another north of Copenhagen, both strategically identified using seismic data acquired by STRYDE's seismic technology.
Impressively, their first geothermal plant in Aarhus is planned to deliver its first heat in September 2025, just 26 months after the seismic acquisition ended.
Once completed, these two projects will collectively deliver over 130 MW of heating through 19 geothermal wells, reducing CO2 emissions by more than 165,000 tonnes annually.
Image caption: Seismic trucks in front of the Danish Parliament in downtown Copenhagen. Photo courtesy of Innargi's Jesper Giørtz Behrens
Before acquiring seismic data, Innargi was operating with limited subsurface knowledge in Copenhagen. Innargi knew geothermal potential existed—thanks to a well drilled 25 years ago that had performed beyond expectations, but they lacked certainty about the extent of the geothermal system. Seismic wasn’t a deciding factor in whether to pursue the project, but rather a crucial tool to confirm their geological model.
Seismic data proved invaluable in identifying areas with geothermal potential and refining their understanding of the system’s extent. A positive surprise was that the system stretched even farther than expected, both north and south, reinforcing confidence in their development plans.
In Aarhus, the seismic survey played a critical role in refining Innargi's drilling strategy within the pre-selected area for geothermal development.
With the site already contracted, the data was essential for pinpointing the most suitable drilling locations, ensuring optimal well placement, and minimizing geological risks.
The seismic data helped Innargi avoid potential hazards, ensuring they didn’t accidentally drill into a fault, which could have had undesirable consequences, ranging from increased operational costs and reduced reservoir efficiency to potential loss of well integrity.
The project challenges:
Innargi deployed STRYDE's autonomous receivers (nodes) to record the seismic data, reduced source efforts near historic and vulnerable buildings and conducted operations at night, ensuring minimal disturbance to the local community. As a result, the survey was virtually invisible to most passersby or local residents. The only indication that a survey was taking place was when the Vibroseis trucks passed quickly through the streets at night for the source operations.
This was relatively seamless, thanks to the proactive communication strategy applied, the modern technology used during the survey, and their flexible approach to survey design and acquisition operations.
To address any public concerns, Innargi leveraged TV, radio, and newspapers to inform the public, reassure them about how minimally invasive the survey would be, and emphasize the long-term benefits of clean heating that would be available to them in just a few years. This transparent approach led to minimal concerns from the public during the acquisition phase.
The deployment of a high-density array of autonomous and miniature seismic technology helped improve coverage and enabled flexible survey design. Subsurface experts from Geo designed pre-plots, calculated and optimized source energy at each vibration point (including drive level, number of vibrations, etc.), accounted for all subsurface features, mitigated the risk of building damage, monitored real-time PPV, managed traffic control, coordinated all permitting, and oversaw the entire operation.
The use of STRYDE’s miniature nodal seismic technology allowed RTS to record seismic data discreetly, positioning the seismic nodes along streets, in bushes, and next to trees, hidden away from the public where possible. Nodes were clearly marked with notes explaining the survey, and amazingly, less than 1% of them were tampered with.
"We were pleasantly surprised by how few nodes were tampered with (less than 1% lost). People were curious but generally respectful. Some even mailed back nodes they had picked up!"
Lead Geoscientist at Innargi
The ability to deploy a dense seismic node network without disrupting road traffic or daily life in the city was crucial, and is one of the many reasons why STRYDE was chosen as the seismic data acquisition system for this seismic survey.
Thanks to the compact size and autonomous functionality of STRYDE nodes, RTS was able to deploy a high-density array with just 10 meters between each node, all while avoiding additional costs.
This dense array, combined with night-time operations to minimize anthropogenic noise interference, resulted in data quality that exceeded expectations.
Image caption: A STRYDE node deployed on the streets of Copenhagen with Vibroseis trucks operating at night.
"In our experience, urban environments are notoriously challenging for seismic acquisition, but the results we obtained on these two surveys were exceptional. The combination of a dense receiver grid, long offsets, and optimized source effort enabled us to produce highly accurate subsurface images."
Founder and Chief Research Scientist, realtimeseismic
STRYDE supplied its Nimble Seismic System — a state-of-the-art solution designed for the rapid acquisition of high-resolution seismic data on land.
Once the data was acquired, RTS processed it with exceptional speed, delivering high-resolution seismic images for Innargi in record time. These insights played a crucial role in refining the geological model, mapping fault lines, and pinpointing the most promising locations for geothermal wells.
RTS migrated images just hours after acquisition to conduct initial checks, with full processing completed within weeks. For the Copenhagen survey, operations wrapped up mid-June, and by mid-July, Innargi were already reviewing the initial data, with the final processed versions and report completed by August.
RTS’s approach contrasts sharply with traditional, larger processing firms, where the process is often found to be slower.
Image caption: An example of the seismic data that Innargi acquired (from Holbæk). Data courtesy of Innargi.
Read the full story and interview with Innargi and RTS to uncover more details about these game-changing projects in the leading geothermal news publication, ThinkGeoEnergy.
