Gas migration in a Cenozoic clay: Experimental results and numerical modelling

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  • UPC - Universitat Politècnica de Catalunya

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Abstract

Gas migration through a potential host clay formation for the geological disposal of radioactive waste in Belgium is experimentally investigated in the laboratory, and numerical modelling is performed to help in the interpretation of the results. Selected air injection tests under oedometer conditions on initially saturated Boom Clay samples with oriented bedding planes are presented. Priority in the experimental programme is given to the study of the deformation response along the injection and dissipation stages, as well as to the analysis of the pore network changes, which detect the opening of fissures that can act as preferential air pathways. The experimental results are simulated using a fully coupled hydro-mechanical finite element code, which incorporates an embedded fracture permeability model to account for the simulation of the gas flow along preferential pathways. The intrinsic permeability and the retention curve of the clay are assumed to be dependent on strains through fracture aperture changes. The numerical results could reproduce upstream/downstream pressures, outflow volume and soil volume change accurately. The experimental results, combined with the numerical simulation, provide good insight into the role of the volumetric response and of the bedding planes on the air transport proper-

Details

Original languageEnglish
Pages (from-to)81-100
Number of pages20
JournalGeomechanics for Energy and the Environment
Issue number2016-04-002
DOIs
Publication statusPublished - 6 May 2016

Keywords

  • gas transport, deep clay, coupled hydro-mechanical response, microstructure analysis, discontinuities opening, preferential air flow

ID: 2118879