Analysis of Archie's parameters determination techniques in carbonate reservoirs

Determination of hydrocarbon saturation is the vital parameter in oil reserve calculation processes. Archie's formula is the water saturation model for the determination of hydrocarbon saturation. The parameters of Archie's formula (a, m and n) are determined through laboratory core analysis program. Determination techniques of Archie's parameters are relatively well known and validated for sandstone reservoirs. But in case of carbonate rocks, there are considerable variations in texture and pore type, so, Archie's parameters become more sensitive to pores pattern distribution and lithofacies properties. Uncertainty in these parameters will lead to non acceptable errors in the water saturation values. In this study three techniques are presented to determine Archie's parameters using carbonate core samples. These techniques are; conventional technique, core Archie's parameters estimate (CAPE) technique and three dimension (3-D) technique. The main objective of this study is to determine Archie's parameters in order to get the most accurate estimate of water saturation by using the above three techniques. Water saturation profiles were produced using different Archie parameters already determined by the three techniques for the studied sections in the wells. These profiles have shown a significant difference in water saturation values, such difference could be mainly attributed to the uncertainty level for Archie parameters from each technique.