[en] Over the last years, Andra has collected an impressive amount of hydraulic data on the middle Jurassic, Callovo-Oxfordian argillite at a site located 300 km eastern from Paris. Preliminary analyses of the formation pressure (freshwater potential) and the hydraulic conductivity have been performed based on the hydraulic data of both the short term packer tests and the long term monitoring (EPG and Westbay). This was performed using numerical borehole simulators which enable taking into account the complete pressure history of the borehole, defining a suitable flow model and deriving best guess estimates and uncertainty ranges of the hydraulic parameters. For all measurement intervals investigated In-Situ, it was shown that the hydraulic conductivity was less than 2,10^-12 m/s. A comparison of the preliminary results of the packer tests and those of the long term pressure monitoring shows that the short term packer tests tend to highly over-estimate the formation pressure. The hydraulic conductivities obtained from the analysis of the packer tests are mostly higher than those obtained from the analysis of the EPG long term recovery. Further analyses are planned to check these preliminary analyses as well as the consistency between short term and long term measurements providing information on rock properties at different scales (different radius of visibility). (authors)