“Electrical Properties” covers a suit of test used to calibrate down hole resistivity tools that are used to determine the water saturation of a reservoir.
The basis of these test was developed by Archie (1942) and involves measuring the resistivity of a partially saturated sample to demine the standard petrophysical terms
- a = Cementation constant
- m = Cementation exponent
- ·n= saturation exponent
While these terms may be suitable for clean reservoirs subsequent tests may be necessary for formations containing significant amounts of clay, which have their own inherent resistivity due to clay bound water layer. The work of Waxman-Smitts and Thomas explains these interactions as well as a set of analytical procedure to quantify the clay corrected exponents (m* and n*) these test include
- Multi Salinity Formation Factor
- Cation Exchange capacity