A measurement of creep and permeability of a salt cavern

Rock mass properties differ significantly from those measured on samples in the laboratory. A test has been performed on a deep brine-filled cavern, w ith the objective of measuring the equilibrium pressure reached when the ca vern was closed. Such an equilibrium is reached when salt mass creep, which leads to cavern shrinkage, balances brine permeation through the cavern wa ll. A K = 2.10(-19) m(2) value of the average in situ intrinsic permeabilit y has been deduced from the test; it is significantly higher than the intri nsic permeability measured in a well or in the laboratory. This result supp orts cavern abandonment scenarios in which the risk of natural fracturation due to high brine pressures is alleviated. ( (C) Academie des sciences/Eis evier, Paris.).