Influence of matrix conduction upon hydrogeophysical relationships in arenaceous aquifers

The relationship of formation resistivity factor to effective porosity or intergranular permeability in water‐saturated sands is shown to be best defined where the solid constituents do not contribute significantly to the conduction of applied current or where corrections for this contribution have been applied to the measured formation resistivities. It is demonstrated that, in the particular case of an argillaceous sand sorted according to its matrix conduction properties, useful relationships between formation resistivity factor and intergranular permeability can be established without any process of correction, provided that porosity and electrolyte salinity do not vary markedly within the formation. This finding is used to resolve the paradox that formation resistivity factor has been reported to increase with intergranular permeability in certain sands and to decrease with increasing values of this same hydrological parameter in others.