Details zur Publikation

Kategorie Textpublikation
Referenztyp Buchkapitel
DOI 10.1144/SP415.16
Titel (primär) Numerical interpretation of gas-injection tests at different scales
Titel (sekundär) Gas generation and migration in deep geological radioactive waste repositories
Autor Shao, H.; Xu, W.; Marschall, P.; Kolditz, O. ORCID logo ; Hesser, J.
Herausgeber Shaw, R.P.
Quelle Geological Society, London, Special Publications
Erscheinungsjahr 2015
Department ENVINF
Band/Volume 415
Seite von 203
Seite bis 212
Sprache englisch
UFZ Querschnittsthemen RU5;
Abstract

To investigate gas-migration processes in saturated low-permeability argillaceous rocks, gas-injection tests under different injection pressures were carried out at different scales: on core samples at the laboratory scale; in the packed-off section of boreholes at the borehole scale (HG-B); and in the sealed microtunnel at the tunnel scale (HG-A) – a 1:2 scale experiment at the Mont Terri Rock Laboratory, Switzerland. All three tests at the Mont Terri Rock Laboratory involved Opalinus Clay. A fully coupled hydromechanical model has been developed that takes account of elastic and plastic anisotropies, anisotropic two-phase flow based on the van Genuchten function, and permeability changes when evaluating the experimental data. Two different flow regimes were studied: two-phase flow under low gas-injection pressure and dilatancy-controlled gas flow under high gas-injection pressure above the confining pressure in the laboratory experiment or the minimal principal stress in situ. When dealing with the dilatancy-controlled gas-flow regime, special consideration was made by applying two permeability approaches in which (i) the permeability change was pore-gas-pressure dependent and (ii) where the permeability change was deformation dependent.

Using the parameter values determined by laboratory data, the in situ borehole tests obtained under well-defined hydromechanical conditions could be analysed accordingly. The gas-flow regime in large-scale experiments, as in the case of HG-A, is mainly governed by experimental circumstances: in this case, the excavation-induced fractures around an opening with a permeability four order of magnitude higher than that in the undisturbed rock mass.

dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=15895
Shao, H., Xu, W., Marschall, P., Kolditz, O., Hesser, J. (2015):
Numerical interpretation of gas-injection tests at different scales
In: Shaw, R.P. (ed.)
Gas generation and migration in deep geological radioactive waste repositories
Geological Society, London, Special Publications 415
Geological Society Publ. House, London, p. 203 - 212 10.1144/SP415.16