Abstract

To measure the true potential of a reservoir, hydrocarbon saturation needs to be determined with good accuracy. In 1942 Archie published a formula to estimate water saturation in reservoirs. In case of carbonates, the saturation computed by the formula is not always correct because of the variability in the Archie parameters; i.e a, m and n. These exponents tend to vary quite often in carbonate reservoirs because of the textural variation in the carbonates. The wettability affects the value of the saturation exponent. These exponents can be estimatated from the cores. However, deriving these components from logs at a hgher resolution has remained a challenge and new probes and techniques are required for a better understanding of these Archie parameters.