Influence of Wettability on Two- and Four-Electrode Resistivity Measurements on Berea Sandstone Plugs

Summary Two- and four-electrode resistivity measurements were conducted on water- and oil-wet Berea sandstone plugs for different saturation directions with a steady-state flooding procedure. The data from nine plugs indicated that reliable resistance values can be obtained on water-wet cores with both two- and four-electrode methods. On oil-wet cores, however, two-electrode measurements yielded higher resistance values than those from the four-electrode method because of end effects and contact resistance, especially for low water saturations. In addition, the saturation history substantially influenced the resistivity measurements of oil-wet cores. The four-electrode technique is better for oil-wet core resistivity measurements because it ensures that correct Archie saturation exponents are derived.