Abstract
Permeameters have been used for more than 80 years in the oil and gas industry, either to measure porous media permeability ("K" studies) or to interpret permeability alterations by various unintended or deliberate processes ("AK" studies). It is the latter experiment class—the AK studies—which are this paper's focus.
Darcy's law is an empirical observation that permeability is proportional to the fluid velocity and the applied pressure gradient, and inversely proportional to the fluid viscosity. In experimental utopia, the simplest variable to measure is the only one that must be recorded during an experiment; however, in practice, interpretation errors frequently arise from ignoring factors that are more difficult to measure or predict, such as viscosity changes within cores during a test. Using data from previously published studies, this paper examines some interpretation pitfalls from past experiments and shows how some of these can be avoided. In addition to ignoring changes in factors that are not actually constant, another pitfall is not fully utilizing the available information. This paper identifies permeametry interpretation improvement opportunities for past or future studies using commonly available data, especially for those tests involving, parallel-flow, dual- or multi-cell tests, or carbonate matrix acidizing optimization studies.
