The energy storage project at the Chemistry Center, University of Lund, was started in May 2004 and completed in November 2005. With a total of 153 boreholes, a depth of 230 meter and Ø 115 mm, the energy storage is one of the largest of its kind in Europe. The geology consists of very compact boulder clay and slate with sections of fine silt and gravel which are prone to flow. Under the boulder clay there is bedrock. In this kind of geology air drilling is a doubtful choice and in order to reach the prescribed depth it was necessary to use Wassara. Main contractor was Malmberg Borrning AB. Project owner was Akademiska Hus.
Result:
Total meters drilled was 32 000. The Wassara system proved to have big advantages in this difficult geology. The risk of borehole collapse was reduced and the Wassara system's ability to drill straight holes was very important since the distance between the wells was only 6 meter.
Equipment:
Hammer
Wassara W100
Bit
Tubex XL 115 for casing advancing, Wassara 115 mm
Pump
Malmberg Borrning AB, Woma-pump 320 l/200 bar
Drilling fluid
Clean water
Drill pipe
3 meter, 4,2-6,3 mm thickness, OD 89 mm
Rig
Nemek 700
Formation
Boulder clay, slate, fine silt and gravel on bedrock
Other
Wassara Swivel Stenberg 600, Wassara Service Equipment WSE-BP W80/W100