A methodology for blank and conformance corrections for high pressure mercury porosimetry

High pressure mercury porosimetry measurements suffer from two well-known systematic errors—blank errors and conformance errors. Blank errors result in an apparent mercury intrusion due to differential compaction of the mercury, sample and measurement apparatus. Conformance errors result from the mercury not completely filling the measurement container at the start of the measurement. A methodology for blank corrections that uses two calibration tables, one built from the experimentally determined apparent intrusion when a measurement is made with no sample present and one built from the apparent intrusion for a single non-porous sample, has been developed. These tables allow the blank effect to be calculated for a non-porous sample of the same material of any size. In principle, the blank material can be numerically constructed to match the mineralogy of the sample. The methodology is illustrated by using quartz blanks to correct measurement curves of two small low permeability samples. The conformance correction problem does not seem to be amenable to a generally applicable objective methodology. If the sample volume is accurately known, it can be used to perform a correction.