IP38: Induced Polarisation

The formations surrounding the borehole are subjected to an alternative square-wave voltage applied via the upper and lower injection electrodes. Following each injection cycle, the resulting potential difference over a section of the formations is analysed as it decreases with time. The form of this decreases curve is related to the chargeability of the formations.

A high chargeability indicates that induced electrochemical potentials are able to develop within the formations as a result of ion transfer between pore fluids and semi-conductive metallic mineral grains present within the rocks.

The IP38 probe is particularly suitable for mining exploration in the context of a disseminated sulphide mineralisation. In the hydrogeological domain, it can also provide qualitative information about the permeability of potential aquifer horizons.