Year 2022 marks the occasion of QHeat drilling five geothermal wells simultaneously for the first time. In Finnoo, Espoo QHeat is drilling two geothermal wells for Finnoon Syvälämpö Oy. In Niittykumpu, Espoo, QHeat will drill three wells for NREP to serve the needs of a full residential block to be built on the site. The target depth of the geothermal wells in both sites is 1500-1600 meters.
The quality of the bedrock determines how deep wells can be drilled. Before starting a new well project, a soil survey will be carried out to assess the possibility of fracture zones, i.e., bedrock subsidence. These areas make drilling difficult and, depending on the technology and expertise available, may halt progress.
“Even though we do thorough bedrock surveys before starting projects, the wells are drilled so deep that no one in the world can say with certainty whether or not we meet a fracture in the bedrock,” says Simo Laitinen, Project Manager at QHeat. Previously, Laitinen has worked in rock engineering projects at publicly listed construction companies YIT and Lemminkäinen.
In Niittykumpu, the fractures have slowed down the drilling of the heat well boreholes but have not prevented the project from going ahead.
“With the working methods developed by QHeat, penetrating the fracture has been successful, and after fortifying the cave-in area, we have been able to continue drilling.”
In Finnoo, the bedrock has proved to be intact, as preliminary studies have suggested, but there have still been coincidences. On 24 June, an incident occurred at Finnoo when a compressed air vent pipe broke off from the weld and pressure was released underground, lifting a section of pipe between the vent and the pit as well soil up from the borehole.
Laitinen sees the challenges posed by Niittykumpu and Finnoo projects as an opportunity to accumulate important data and experience on challenging drilling environments.
“We are drilling thermal wells in conditions that no one else has ever worked in before. It is through experiences like this that QHeat’s drilling and thermal well technology evolves,” says Laitinen.
At the same time, important practices are being established in the industry to facilitate the construction of geothermal heat wells.
“There are no established practices in the geothermal sector yet. Common procedures and ways contribute to successful drilling as well as safety.”
Both Finnoo and Niittykumpu thermal well projects are expected to be completed during 2022.
Image: QHeat CTO Rami Niemi, Head of Drilling Rauno Sipilä and Project Directors Simo Laitinen and Tomi Kimari at Finnoo construction site.