test_moissonnage_selune
type: Agent

Detection and migration of gases in geological media: Experiments and numerical simulations at the Roselend Natural Laboratory
type: Distribution
access URL: https://theses.hal.science/tel-00965028
format: HTML
issued: 2026-05-05T21:18:24.678311
modified: 2026-05-05T21:18:24.579170

Detection and migration of gases in geological media: Experiments and numerical simulations at the Roselend Natural Laboratory
type: Dataset
contact point: Organization
  fn: CCSD
keyword: advection
keyword: xenon
keyword: sdustusciences-of-the-universe-physicsearth-sciences
keyword: traite-dinterdiction-complete-des-essais-nucleaires-tice
keyword: permeability
keyword: permeabilite
keyword: infiltration
keyword: tracages
keyword: fractures
keyword: simulation-numerique
keyword: radon
keyword: unsaturated-zone
keyword: theses
keyword: barometric-pumping
keyword: pompage-barometrique
keyword: gas
keyword: infoeu-reposemanticsdoctoralthesis
keyword: helium
keyword: sf6
keyword: numerical-simulation
keyword: tracing-experiments
keyword: co2
keyword: comprehensive-nuclear-test-ban-treaty-ctbt
keyword: gaz
keyword: zone-non-saturee
landing page: https://theses.hal.science/tel-00965028
description: Gas migration in rocks results from natural and artificial processes. Understanding gas migration matters for the Comprehensive Nuclear-Test-Ban Treaty (CTBT), to improve the detection of underground nuclear explosions by their radioactive gases. This work concerns many other fields in Earth Sciences, for fundamental as well as applied science. Issues in improving the detection and the understanding of gas migration in geological media are the following. What are the driving forces of gas migration from depth to the surface? How much of the gases produced at depth do arrive at the surface? Does this migration lead to temporal delays and dilution between production and breakthrough at the surface? To answer these questions, this thesis is dedicated to the identification of gas transport mechanisms in fractured rocks, from both field experiments and numerical simulations. The Roselend Natural Laboratory (French Alps) is a unique facility for studying gas transport in the unsaturated zone at the field scale, representative of natural processes. Parameters and external forcings have been determined. A tunnel and an isolated chamber, at 55 m depth, as well as boreholes at depth and at the surface, allow to monitor gases that are present in the rocks. Pneumatic properties of the rocks, permeability and porosity, were determined at scales ranging from 1 to 55 m, from both pneumatic injection tests and pressure monitoring as well as from computational studies of fluid flow and transport in porous media. Inverse modeling was used to quantify the associated uncertainties. The results underline the strong spatial heterogeneity of fractured media. The natural dynamics of three gases, CO2, SF6 and 222Rn, was monitored continuously for more than one year. The results, interpreted with numerical simulations, determined that the processes controlling the natural dynamics, or baseline, of gases are atmospheric pressure fluctuations and water movements. Such water movements also expl…
issued: 2026-05-05T21:18:24.612895
language: fr
modified: 2026-05-05T21:18:24.612900