5. CONCLUSION                                

The result of electrical resistivity measurement of sandpacks using a four-electrode technique have shown that the spatial distribution of brine in the pore space affects the measurement of electrical resistivity. If the brine is in the area between two potential electrodes (P1 and P2), the resistivity will be significantly reduced. Meanwhile, if the brine is outside the area between the two potential electrodes, the resistivity is not considerably reduced. In addition, observations of partial saturation measurement suggest that the critical brine saturation occurs when the brine has passed the upper electrode potential (P1) at exact saturation around 0.7–0.8 for all samples.
Electrical resistivity in samples that have larger grain sizes is always higher than samples that have smaller grain sizes in the area before the critical brine saturation. This result is related to the permeability of the samples and the surface tension between brine and grain. Moreover, the calculation of electrical resistivity through Archie's equation and finite element method only applies to samples that have a good brine distribution in the area between two potential electrodes.