Investigation of Empirical Equations for Calculating Cementation Factor, In Carbonate Asmari Formation; The West Southern Iranian Oil Field

Calculation of water saturation plays a major role in formation evaluation. Archie formula is one of the fundamental methods for calculating the water saturation of formation which contains laboratory measured parameters named Archie coefficients. When there is no access to laboratory measurement results, the Archie constants are used. Due to the heterogeneity and structural variety in different carbonate rocks, Archie constants lead to so many calculation errors. In this study, Archie coefficients have been determined for Asmari formation carbonate rocks through experiments; then some important empirical equations have been used in order to calculate Archie coefficients and compare them with the measured ones; eventually a relationship has been established between porosity and cementation factors. Results indicate that Borai formula has the best accordance with experimental data; but in order to use its formula, we must swap the coefficients with observed experimental data. Results also suggest that the experimental data have coefficient of correlation equaling 76 percent and we will witness better results provided that there are isolate samples with porosity lower than 5 percent.