Asadollahi
Keramati
Haghighi - Engineering Faculty,Tehran University
Bagheri

The estimation of the OOIP is one of the important calculations of the field development and management. The OOIP is usually calculated by either volumetric method or material balance studies. In both calculations the water saturation determination is necessary . In 1942, Archie’s laboratory experiments established a relationship between porosity, water resistivity, rock resistivity measured by the log and water saturation. Archie’s equation could evaluate hydrocarbon reserves continuously versus depth with much less cost and effort with respect to previous method. Based on log interpretation and core analysis data of an Iranian carbonate reservoir the appropriate distributions for saturation equation parameters are fitted. Then, the uncertainty and the relative importance of parameters are evaluated by means of a Monte Carlo type simulation, where the relevant properties are drawn from fitted distributions for Archie’s parameters and combined into an estimate of water saturation, through the relevant equation for this case. At the end, the effect of cementation factor on OOIP is studied. The results of this analysis show that porosity and total resistivity are the most important parameters affecting uncertainty in Archie’s water saturation equation in the proposed reservoir. Also, a new practical correlation has been presented for cementation factor as a function of porosity. Using the practical correlation for eevaluation of water saturation uncertainty in proposed reservoir has decreased the amount of water saturation uncertainty.

Monte-Carlo, Sensitivity, Uncertainty, Cementation, Archie, Correlation