Interest in the hydraulic and mechanical characterization of shales has grown in recent years, because of their application in the context of energy geotechnics. In the frame of nuclear waste disposal shales are considered as host formations for the placements of nuclear waste at high depths. In the frame of hydrocarbon production they are considered as unconventional reservoirs, from which extracting natural gas. Understanding how fluids flow through shales is then a key aspect for both fields of application. This paper focuses on the analysis of the transport of water vapour through laboratory samples. After reviewing the balance and flow laws that govern the transport of fluid in unsaturated porous media, a simplified model is put forward. The model was implemented in a commercial finite element code, and it was used to reproduce the results of a literature study on wetting and drying of Opalinus Clay shale samples, imposed through the vapour equilibrium technique. Back analysis of the water content and volume strains of these specimens suggests that existing models underestimate the actual flow rate of water vapour which takes place at low suctions. The current interpretation also seems to be consistent with microstructural investigations on the interconnection between large pores of this material.
Numerical investigation on water exchange of shale samples / Incollingo, S.; Ferrari, A.; Musso, G.. - In: E3S WEB OF CONFERENCES. - ISSN 2267-1242. - 195:(2020), pp. 1-6. (Intervento presentato al convegno 4th European Conference on Unsaturated Soils, E-UNSAT 2020 tenutosi a prt nel 2020) [10.1051/e3sconf/202019502025].
Numerical investigation on water exchange of shale samples
Incollingo S.;Musso G.
2020
Abstract
Interest in the hydraulic and mechanical characterization of shales has grown in recent years, because of their application in the context of energy geotechnics. In the frame of nuclear waste disposal shales are considered as host formations for the placements of nuclear waste at high depths. In the frame of hydrocarbon production they are considered as unconventional reservoirs, from which extracting natural gas. Understanding how fluids flow through shales is then a key aspect for both fields of application. This paper focuses on the analysis of the transport of water vapour through laboratory samples. After reviewing the balance and flow laws that govern the transport of fluid in unsaturated porous media, a simplified model is put forward. The model was implemented in a commercial finite element code, and it was used to reproduce the results of a literature study on wetting and drying of Opalinus Clay shale samples, imposed through the vapour equilibrium technique. Back analysis of the water content and volume strains of these specimens suggests that existing models underestimate the actual flow rate of water vapour which takes place at low suctions. The current interpretation also seems to be consistent with microstructural investigations on the interconnection between large pores of this material.File | Dimensione | Formato | |
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SI_AF_GM_2020_EUNSAT_Numerical investigation on water exchange of shale samples.pdf
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Descrizione: studio numerico sul processo di desaturazione di una shale esposta a umidità relativa imposta
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https://hdl.handle.net/11583/2858736