Geophone double packer system
The double packer system was developed, built and successfully used in stimulation tests by Solexperts for Geo-Energie Suisse as part of their involvement in the Bedretto rock laboratory. The test tool essentially consists of a double packer system for stimulation and a series of geophones which are used to measure and localise the seismic events of the hydraulic stimulation.
Tree geophones are emplaced below the double packer at several metres distance, which are pressed against the borehole wall with packers to achieve an optimal connection of the geophones to the rock formation. The stimulation in the borehole section isolated with the double packer generates seismic events that can be measured and localised with the signals from the three geophones. The geophone packer system was successfully tested in the Bedretto rock laboratory in an inclined approximately 350 m deep borehole.
"We succeeded in increasing the water permeability by a factor of 10 to 100 in the compact granite of the Gotthard massif with the help of targeted stimulation measures and in measuring and controlling the microquakes necessary for cracking."
Quote from Geo-Energie Suisse Director, Peter Meier