Electro-kinetic measurements as a function of frequency and rock deformation: theory, experiment, modelling and applications

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Fluid flowing through rocks and soils cause an electrical potential to be developed in the opposite direction. This is an electro-kinetic process which may, in future, be extremely useful. The main reason for this is that we can measure the electrical potential within the Earth`s crust from the surface. If we know how the electro-kinetic mechanism works, it should be possible to monitor the flow of fluids deep down. Between 1997 and 2003 a complete steady-state theory of electrical conduction in rocks and soils was developed by Paul Glover (the applicant) and others. Since then the applicant`s research group has made major progress in developing theories that include the microstructural properties of the rocks and soils, and the effect of frequency, and they have constructed devices for measuring both steady-state and frequency-dependent streaming potentials, which is the name given to the induced electrical potentials. The group has applied these advances to fluid flow in volcanoes, geothermal, water and hydrocarbon reservoirs, earthquake mechanisms, rock permeability, transformations between grain diameter and pore radii, and seismoelectric exploration. It is clear that many more applications exist including minitoring of shale gas extraction,and some which are well outside the geosciences, in civil engineering, environmental egineering and even biology and food science. This grant will enable us to (i) make a large number of laboratory measurements of electrokinetic properties for different rocks, sands, soils which are saturated with fluids of different chemistry, salinity and pH, (ii) to make measurements as a function of frequency and grain size, (iii) to make measurements while the rock is being deformed, (iv) to develop theoretical models and test them with the data, (v) to use the data and theory to model and solve problems involving volcanoes, earthquakes, radon gas, permafrost melting, oil, gas and water reservoirs and seismo-electric exploration.