A method can include receiving porosimetry data for a range of pressures that spans a transition zone defined at least in part by a high-pressure end of a first pressure zone and a low-pressure end of a second pressure zone; detecting at least one artifact in the transition zone; computing accuracy information for the high-pressure end of the first pressure zone and the low-pressure end of the second pressure zone; computing a pressure-volume adjustment based at least in part on the accuracy information; and outputting a pressure-volume relationship in the transition zone based at least in part on the pressure-volume adjustment.