Permeability prediction of four Egyptian sandstone formations

Reliable formation evaluation for oil and gas reservoirs or the modeling of groundwater flow requires accurate information on petrophysical properties such as permeability or porosity of the reservoir rocks. Porosity can be easily determined both in the laboratory and from well logs. Accurate experimental permeability determination requires more expensive methods. As an alternative, physical models and/or empirical equations have been proposed to enable permeability prediction based on more easily measurable parameters. This paper evaluates five models and formulae for permeability estimation based on petrophysical parameters that are related to pore space geometry. The fundamental parameters that are related to pore size or specific internal surface were determined by nitrogen adsorption, nuclear magnetic resonance, and spectral induced polarisation measurements. Petrophysical parameters of 96 sandstone samples from four sandstone formations in Egypt were included in this study. The comparison of the predictive quality of the models provides more insight into the limitations of the individual models. The roughness of the internal surface, the clay content, the connectivity of the pore space and the distribution of iron minerals are identified as the most relevant properties affecting the predictive quality of the models.