Hydraulic characterisation of host rocks
Country / Region: Germany
Begin of project: January 1, 1998
End of project: December 31, 2024
Status of project: March 26, 2024
Flow paths and losses from a packer test which need to be taken into consideration during evaluations
Source: BGR
The barrier effect of geological host rocks for a potential geologic repository for radioactive waste is attributable to the absence of interlinked pore space systems. The geotechnical determination and characterisation of the barrier effect is undertaken by means of hydraulic tests and then by deriving hydraulic parameters (e.g. the permeability).
BGR carries out in-situ measurements using a range of different packer systems to determine the hydraulic permeability of rock formations. The measurements are carried out in exploration facilities and international underground laboratories.
Because of their very low permeability values (salt << 1.E-20 m², clay < 1.E-19 m² and granite < 1.E-18 m²), very high demands are placed on the tightness of the technical equipment. The measuring equipment is regularly tested to identify any potential leaks, and where required, the necessary measures are implemented to guarantee a minimum level of tightness. System-related influences on the measurement results are taken into consideration by using a specially-developed calculation model, to ensure the most accurate possible determination of the permeabilities of rock formations, even in very tight rocks.