The factors that influences the electrical properties of a geologic material are; porosity, the water content or saturation, water rock interaction and alteration, the resistivity of the water, the clay content, temperature, pressure and the content of metallic minerals in the formation. This laboratory research work was carried out with the key objective of establishing the relationship and the effect of porosity and water saturation on the electrical resistivity properties of earth materials.
A table top basket test was carried out where two of the factors (i.e. porosity and water saturation) were controlled in order to observe the corresponding electrical resistivity property of the concerned geologic unit. The table top basket was turned to the earth’s subsurface by adding choice homogenous geologic material. The electrical properties of the soil was obtained through electrical resistivity techniques using Wenner Electrode configuration (constant separation techniques. Measurements were taken in the totally dry sand basket as a reference. The same procedure was repeated for three other instances; when porosity was increased, when water saturation was increased and when porosity was reduced.
The obtained curves show positive trends with high resistivity values obtained from small electrode separation and high values obtained from large electrode separation distances. Analysis also revealed that increase in water saturation of the geologic material lowered the resistivity value by 70%, a reduction in porosity of the geologic material increased the resistivity value by 27%. This study concludes that; water saturation and porosity has an inverse relationship with the electrical resistivity properties of geologic materials.
Keywords : Compaction, Electrical Resistivity, Geologic Material, lithification, Porosity Effect, and Water Saturation.