Hydraulic Pumping Tests in Very Deep Boreholes in Rock. Theory of Pressure Oscillations Induced by Elasticity and Inertia of the Test Equipment

In geohydraulic the hydraulic conductivity and diffusivity of rock are measured by means of pumping tests with double packer conductivity meters in boreholes. If the borehole is very deep the measured pressure and flux oscillate. The oscillations, which are caused by the inertia and elasticity of the equipment, make conventional evaluation of conductivity difficult. A theoretical analysis including the inertia and elasticity is derived and the coupled partial differential equations are solved in closed form. The conclusion is that the oscillations can be used for determining the conductivity and the diffusivity of the rock. The analysis also shows that the complete analysis including the oscillations makes the flux reach steady state faster than conventional analysis predicts.