An Analysis Of Porosity And Dispersivity Of Porous Media Using Self-Potential Method

As one of the important geophysical exploration methods, Self-potential method has been widely used in hydrology geology field. Self-potential method have one special advantage that it can directly describe the flow of underground water and transport of solute.There are two theories used for analyzing self-potential data:Coupling theory and Uncoupling theory. Computation of Coupling theory is more complex and time-consuming. Computation of Uncoupling theory is easier. But no record shows that is there anyone successfully fitting the experimental self-potential data with modeling self-potential data before. In this study, we can get the porosity and dispersivity through salt pulse experiments in sand column and sand box. By analyzing the self-potential data of these experiments by Uncoupling theory, porosity and dispersivity can be obtained.By completing rounds of experiments, the results reveal the following conclusions.(1) Uncoupling theory is reliable because of its strong theory background. Besides, porosity and dispersivity can be directly obtained by fitting experimental self-potential data and modeling data using uncoupling theory.(2) Percolation theory can be used in both homogeneous condition and non-homogeneous condition. But Uncoupling theory can’t be directly used in non-homogeneous condition.(3) Porosity and dispersivity obtained by uncoupling theory and precolation theory are both field parameters. Besides, porosity obtained by these two theory is active porosity. That is these pores are where water flows by.(4) In two dimension condition, Self-potential method can be used to describe the field of water flow and salt transport.In two dimension condition, salt transport can be obtained by contour of self-potential data and contour of responding-time.