Hydraulic fracturing in field permeability testing

Field studies at the Dead Sea, Israel, and in Oslo have indicated that serious errors may be introduced in estimating the permeability of fine-grained clay soils using in situ tests if excessive water pressures are used, a fact already appreciated by rock and petroleum engineers. Model laboratory tests in London have confirmed that very low pressures must be employed and a mathematical analysis has been developed to indicate the factors which influence the allowable pressure. By inducing fracture the existing stresses in the ground may be estimated. Des etudes sur place, effectees dans la Mer Noire, en Israel, et a Oslo, ont montre que l'on peut introduire de graves erreurs dans l'estimation de la permeabilite des sols d'argile a grains fins en se servant d'essais in situ au tours desquels la pression d'eau est excessive, un fait experimental qui a deja ete demontre par les specialistes en mecanique des roches et an genie du perole. Des essais sur modele au laboratoire, a Londres, ont confirme que l'on do...