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Gas Flow Through Water-Saturated Shear Zones: Field and Laboratory Experiments and Their Interpretation

Published online by Cambridge University Press:  10 February 2011

P. Marschall ,
J. Croisé ,
U. Fischer ,
R. Senger  and
E. Wyss
P. Marschall
Affiliation:
Nagra, Swiss National Cooperative for the Disposal of Radioactive Waste, Hardstrasse 73, CH-5430 Wettingen, Switzerland, marschall@nagra.ch
J. Croisé
Affiliation:
Colenco Power Engineering AG, Mellingerstrasse 207, CH-5405 Baden, Switzerland, cro@colenco.ch
U. Fischer
Affiliation:
Institute of Terrestrial Ecology, Eidgendssische Technische Hochschule Zurich, Switzerland
R. Senger
Affiliation:
Intera Inc., 9111 Research Blvd., Austin, Texas, USA, 106403.2160@compuserve.com
E. Wyss
Affiliation:
Solexperts AG, Ifangstrasse 12, CH-8603 Schwerzenbach, Switzerland
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Abstract

Gas threshold pressure tests and gas tracer tests have been performed at the Grimsel Test Site to study two-phase flow processes in a shear zone. In addition, capillary pressure and gas permeability measurements were carried out in the laboratory on drillcore samples. The laboratory investigations were complemented by assessing the pore structure of the shear zone material. The interpretation of the field tests with numerical models indicated that the structural and two-phase flow parameters to be determined are highly correlated with one another and, consequently, the parameter estimates can be rather uncertain. The joint interpretation of field and laboratory results, however, led to a more stringent description of the two-phase flow processes, expressed by a better overall fit of the test data and smaller uncertainty ranges of the estimated parameters. The results showed that the gas mobility in the shear zone was very high even at high water saturation and gas flow was limited to the narrow zones of brittle deformation along the shear zone.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 506: Symposium – Scientific Basis for Nuclear Waste Management XXI , 1997 , 741
Copyright
Copyright © Materials Research Society 1998

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References

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