DESTRESS Project, 14-fold sliding sleeve multi-packer system
Bedretto Underground Laboratory for Geoenergies BULG
As part of the DESTRESS project, Solexperts was contracted to design, manufacture and install a 14-fold sliding sleeve multi-packer system (MPS) in borehole ST1. The objective of the DESTRESS project is to demonstrate the feasibility of generating a geothermal reservoir with multi-zonal stimulation and to improve the understanding of the interaction of hydraulic fracturing and induced seismic events.
Test site
The test site is the Bedretto Underground Laboratory for Geoenergies (BULG) in southern Switzerland near Airolo. The BULG is located 2 km from the south entrance in an old access tunnel of the Furka base tunnel. It is lies in the Rotondo granite and has an overburden of about 1100 m.
Borehole ST1
Length: 400 m
Inclination: 45°
Diameter: 8.5 "
Frac pressure: 20 - 30 MPa
Specifications of the Sliding Sleeve Multi-Packer System
- 3.5" central tube
- 14 high pressure packers
- 14 interval sections
- 14 sliding sleeves
- Pressure and temperature are measured in each interval by in-situ sensors
- In the lowest interval, a geophone registers seismic activity. It is pressed against the borehole wall by a smaller packer in a clamping mechanism
- Over the entire length, the system is additionally equipped with a heatable fibre optic cable for heat pulse measurements and distributed acoustic measurements (DAS)
