St1 geothermal heating plant

A significant milestone for ST1’s geothermal pilot project was the successful completion of the probe drilling stage. Using its diamond drilling method, KATI Oy drilled a hole of 2,015 metres, which reached completion on 10 July 2015. This was the deepest hole ever drilled by KATI.

During the probe drilling stage, the necessary data about the soil was obtained for the purpose of the actual geothermal wells. With a diameter of seven centimetres, drilling took around ten weeks, after which the rock samples were analysed in great detail. These measures provided extra information about the feasibility of the site for drilling the actual seven-kilometre production wells.

The probe drilling went without a hitch, as the rock was solid and very hard for the entire distance. Despite the drill hole reaching record depths, it was completed ahead of schedule. The drill rig developed and built by KATI worked perfectly in this demanding project. The closed circuit equipment, which was used for the cleaning and recycling of drilling water, operated well in line with the demands set by the urban surroundings.

The probe drill hole serves the interests of a number of different bodies. Scientific study is also being created around the project: The soil and water, tens of millions of years old, extracted from the geothermal wells provide unique material for scientific research.

Tero Saarno
Production Manager
St1 Deep Heat Oy