Comparison of Different Logging Techniques for Porosity Determination to Evaluate water Saturation

Abstract

The purpose of this work is to evaluate the saturation profile of Zubair formation in East Baghdad Field, from log interpretation. The relative accuracy of four methods of porosity evaluation, from three porosity logs (Neutron, Density and sonic logs ) , was tested against measured porosity from cores of eighty nine chosen intervals. The accuracy of each method was evaluated statistically by calculating the correlation coefficient, standard deviation error, average percentage error and absolute average percentage error. The crossplot technique (using triangle method ) of Neutron and Density logs data was found to give the best statistical parameters, hence, it was used to calculate optimum porosity values. It is concluded that the adoption of this method in porosity determination will result in more accurate water saturation determination particularly when using Archie's equation.