AN EMPIRICAL APPROACH TO THE DETERMINATION OF POROSITY, SHALE PERCENTAGE, AND PERMEABILITY OF PERMIAN SANDSTONES IN THE COOPER BASIN, SOUTH AUSTRALIA

Abstract

Because of the limited yet adequate logging program run in Cooper Basin wells, porosity has been the most difficult parameter to calculate on a zone-by-zone basis. Empirically derived porosities from a gamma-ray (GK)-sonie (Δt) cross-plot show good agreement with core values of porosity. Furthermore shale percentages calculated from these porosities are in good agreement with shale values derived from crossplot techniques involving sonic, density and neutron log response parameters. An approximation of permeability may also be derived from a further simplified chart.