Theoretical Model For The Geo-Electrical Response Of Fresh Water Shaly Sandstones

The electrical behavior of a shaly sandstone<br>aquifer saturated with freshwater is analyzed<br>based on the volume-conductivity approach<br>proposed by Lima and Sharma (1990; 1992). Such<br>an approach has been shown to be satisfactory to<br>describe both laboratory and well log data under<br>saline water saturation. Here we shown that the<br>electrical behavior and the convex-upward<br>curvature of a plot of the bulk conductivity against<br>the electrolyte conductivity reflect not only the<br>textural and clay mineralogic effects, but also<br>those due to the salinity of its pore electrolyte.<br>Analytical expressions are written both for the<br>conductivity of the aquifer and of their constituent<br>elements. They are written in a form that<br>emphasize the conductive behavior of shaly and<br>clean sandstones, with fresh pore fluid, as<br>demonstrated by several experimental laboratory data.