Comparison Analysis of Water Resistivity Measurements for a Giant Carbonate Reservoir in Middle East

We aim to investigate various calculation methods for water resistivity to figure out to what degree these calculations are consistent. Such analysis helps us to understand how much we can rely on the calculated water resistivity particularly for carbonate reservoirs which are usually very complex in terms of the geological structure. To approach this scope, we calculated Rw using SP-method and Archie equation. The results were then compared against Rw measured from water samples where the latter was utilized as a reference. We found that the calculated water resistivity using Archie Equation resulted in notable fluctuation in Rw value between the wells understudy. The SP-method gave more stable results, however. Apart from one well, each calculation method gave Rw value that did not match the Rw obtained by the other method. Further, none of these was consistent with Rw obtained from the water samples. Such notable variation in Rw indicated that the need to more detailed analysis of Rw is highly recommended to accurately one can estimate water saturation.