Application of the acoustic–electric method to estimate the mineralisation of natural water in contact with rocks

In this study, mechanical-electrical transformations were excited in heterogeneous solid materials. Electromagnetic signals were excited in rock samples via determined acoustic pulses. The main patterns of changes in the electromagnetic signals' amplitude–frequency parameters at the contacts of the rock samples with distilled and mineralised water were determined. We find that contact with distilled water decreases the electromagnetic signal and spectral component amplitudes, while contact with brine leads expands the spectrum. The laws determining the changes in the parameters of the electromagnetic signals and their spectra in porous sandstone samples saturated with water or salt solutions are given. Based on our results, a method is proposed to quantify the salinity of natural water contained in oil or other sources based on changes in the electromagnetic signal parameters when such water comes into contact with rocks.