The approximately 500 km² area has previously been designated by state geologists as a potentially suitable site for CO2 storage. Before any application for the establishment of a storage facility can be considered, Harbour Energy must collect data on the subsoil using advanced seismic technology.
Seismic surveying is a method of mapping the structure of the subsoil using sound waves, which are primarily generated by special trucks sending vibrations into the ground. The sound waves travel down through the layers of the earth and are reflected back. As the waves are reflected differently in the transition between layer types such as clay, sandstone and limestone, it is possible to create a very accurate three-dimensional image of the subsoil and its many layers.
“Now we can finally get started on the survey, which we have been preparing thoroughly for a long time. The results of the survey will form a very important part of the assessments of whether the subsoil in the area can be used for safe and permanent CO2 storage in the long term,” says Henrik Busk, exploration manager at Harbour Energy and responsible for the seismic survey.
The survey will be carried out by the French company S3 Smart Seismic Solutions, Europe’s leading provider of geological surveys. They have extensive experience from many countries, including Denmark, where they conducted a similar survey on Lolland earlier this year.
How the survey will be conducted
The seismic survey will be conducted in five stages. The first stage is already underway. This involves registering the 160,000 points where geophones are to be placed. The work is being carried out by three teams, each consisting of a couple of employees from S3 Smart Seismic Solutions. In rural areas, this is done by inserting a half-metre-long bamboo stick into the ground. In urban areas, a small cross is drawn with biodegradable paint, which disappears after a few weeks. Each team has a Danish-speaking employee from Rambøll attached to it, who helps to comply with all agreements with landowners and can answer questions from curious passers-by. This work will take place from 10 to 22 December and will continue after the New Year for approximately four weeks.
From 9 January, the geophones will be placed at the marked points so that they can pick up signals from underground. The laying of geophones, which is done on foot, will start on 9 January and continue until 18 February.
The vibration trucks will start operating on 15 January and will follow their routes around the area until the end of February. Once data collection is complete, the area will be cleared up – all geophones and bamboo sticks will be collected on foot so that the area looks as it did before.
The collected data will then be processed and analysed in highly specialised computers, which will take several months. The result will be a detailed, three-dimensional image of the geological layers of the subsoil, which will be used to assess whether the area is suitable for safe and responsible CO2 storage.
Dialogue with landowners and neighbours
Since the spring, Harbour Energy has been in close contact with the many landowners in the area, who have had the opportunity to ask questions and gain clarity about what the survey entails – both on their properties and more generally. All parts of the seismic programme have been planned in close collaboration with the relevant authorities and affected citizens, and with great consideration for the surrounding area.
“It has been incredibly informative to meet the landowners, whether at their homes for coffee in their kitchens, at a trade fair in Randers or at an open office event in Asferg. Everywhere we have been met with great understanding and curiosity. Every single conversation provides valuable insight into citizens’ concerns, attitudes and wishes. We want to continue the close dialogue and will be inviting people to an open house event early in the new year, where they will be able to see and experience a vibration truck in action and talk to us about the project,” says Regitze Reeh, Head of Communications at Harbour Energy.
