Evaluation of Petrophysical Properties Using Imaging Techniques

Abstract

The petrophysics science is concerned with the study and characterization of oil and gas reservoirs for the hydrocarbon potential availability and productivity through the quantitative of rock properties. Porosity is one of the most important property in petrophysics. Estimation of porosity values are classified into two techniques, direct and indirect methods. The direct method has been used to estimate the porosity from core analysis, because the well log records are considered as indirect technique, which depend on the measurments of the physical features related with the porosity values. In this study two methods are used to evaluate the porosity of carbonate reservoir. The first one has been applied to the well logging interpretation, while the second method uses imaging technique interpretation based on core slides. The result of the second method shows a more accurate results of porosity in comparison with first method. The porosity values are varied from 2% to 3% by using Neutron log, while the density and sonic logs recorded about 9%. The optical image results of the porosity are ranging from 6.2% to 19.1% at 40 X magnifications, and from 1.8% to 4.6% at 100X. The SEM image interpretation results are: 12.2%, 10.4, % 4.1%, 5.9% at 400X, 1.99KX, 5.01KX, and 10KX respectively. Finally, the results showed that accuracy of porosity values depends on the examined area of sample that the area of sample is changing with the magnification of microscopes types.