Gas Injection Laboratory Experiments on Opalinus Clay - Experimental Set-up and Preliminary Results

SUMMARY Preliminary innovative tests are currently being performed on undisturbed Opalinus clay. These experiments intend to determine the conditions under which gas breakthrough processes occur, as well as to determine the relevant hydro-mechanical parameters that appear to affect these processes. An instrumented high-pressure triaxial cell is used, which was specifically designed to apply isotropic / anisotropic stress states while injecting gas at controlled volume rate. The study is mainly focused on maximum peak pressures, time for breakthrough, measured flows into and out of the specimen, preferential pathways created, induced desaturation of the sample, and relationship of initial peak pressure with total stress state.