Geographical data management software Res1D

interfacemeasurementflow

The Induced Polarisation (PI) is an electric phenomenon that occurs inside of material media in the time domain, with the release of stresses upon the interruption of a flow of electric current of step type (in this case, it is measured as chargeability) and also in the frequency domain, with a precise dispersion law of the electric resistivity upon the variation of the frequency of an alternated current flow. A PI source is connected to the oxido-reductive processes along the interface between the metal grains and interstitial fluids (electrode polarisation). Another important PI source consists instead of ionic accumulations in moving electrolytes due to mobility variations along the path (electro-kinetic polarisation). The tomographic inversion of the data obtained on the surface returns the ground in “output” based on chargeability images, thanks to which it is possible to identify possible accumulation areas or significant concentrations of hydrocarbons. The chargeability is proportional to the charge stored by the lithotype and it represents the concentration of a conductor in the multi-electrode area. This type of survey is carried out with the purpose to reconstruct an electro-tomography 1D for a measurement point. The geo-electric method consists in the experimental determination of the resistivity distribution characterising the electric structure of a medium. In the SEV method, the distance between the electrodes is increased progressively and the ratio between d.d.p. and the current intensity is measured from time to time.