ABSTRACT The problem of defining flow units in carbonate reservoirs has been investigated by integrated geological, petrophysical, and geostatistical outcrop studies. Results show that flow units (mappable intervals with similar petrophysical properties) can best be defined in terms of rock-fabric fades. Geostatistical analysis indicates that the different rock-fabric facies defined are significantly different but that within rock-fabric facies the petrophysical properties are near random. Detailed outcrop mapping shows that rock-fabric units are systematically arranged within genetic packages that have predictable stacking patterns within a sequence stratigraphie framework.