LIMITS OF STANDARD PETROPHYSICAL LABORATORY PERMEABILITY MEASUREMENTS

Although the basic concept of permeability is well-defined empirically by Darcy’s Law, standard petrophysical experimental methods used to measure this value in many laboratories are limited by the maximum permeabilities that can be accurately measured. These limits may not be appreciated by practitioners and scientists who submit cores. A review of literature reveals that maximum permeabilties reported for clastic and carbonate rocks are 2 ∙ 10^-11 m² and 5 ∙ 10^-11 m², respectively. Based on the Poiseuille equation for pipe flow, we can anticipate that significantly higher permeabilities should exist in certain types of rocks. For example, macroporous rocks exhibiting centimeter-scale touching-vug porosity can be estimated to have permeabilties on the order of 10^-5 m². We hypothesize that one of the sources of the permeability limits is related to the gas flow connections to the routinely-used Hassler sleeve core holder.